Temporomandibular disorders among Sami women745766/FULLTEXT01.pdf · Temporomandibular disorders...

Temporomandibular disorders among Sami women Perspectives based on an epidemiological survey with mixed methods

Christina Storm Mienna

Department of Odontology

Umeå 2014

Responsible publisher under Swedish law: the Dean of the Medical Faculty

This work is protected by the Swedish Copyright Legislation (Act 1960:729)

ISBN: 978-91-7601-121-8

ISSN: 0345-7532

©Christina Storm Mienna

Cover photo: Nieidabákti, photographed by Ingrid Storm

Cover pattern: Olav Svonni

Layout: Inhousebyrån, Hans Karlsson

Elektronisk version tillgänglig på http://umu.diva-portal.org/

Printed by: Print & Media

Umeå, Sweden 2014

To Alexander

“Just as the mountain spring flows, so is

life. It is like a river we cannot stop, but

can only try to accept.”

(Quotation from a 48-year-old woman)

”Precis som jokken rinner, så är vårt liv.

Det är liksom ett flöde som vi inte kan

stoppa, utan får försöka acceptera.”

(Citat från kvinna 48 år)

i

Table of Contents

Table of Contents i Abstract iii Abbreviations v Populärvetenskaplig sammanfattning på svenska vi Bealledieđalaš čoahkkáigeassu davvisámegillii viii Original papers x Preface xi Introduction 1

The Sami population 1 Temporomandibular disorders 3 Terminology 3 Classification 4 Etiology 5 Epidemiology 6 Gender differences 7 Co-morbidity 9 Consequences 9 Mixed methods 10 Rationale 12

Aims 13 Study population and methods 14

Study population 15 Methods 20 Questionnaire (Paper I and III) 20 Clinical examination (Paper II) 20 Statistical methods (Papers I-III) 23 Thematic interviews (Paper IV) 24

Results 27 Study population 27 Symptoms indicative of TMD 27 Headaches and neckshoulder pain 29 Disability related to symptoms indicative of TMD 29 Disability related to headaches and neckshoulder pain 30 Co-morbidities 31 Case–control study 32 Thematic interviews 35

Discussion 41 Main findings 41 Study population 41 Methodological considerations 43

ii

Ethical considerations 46 Temporomandibular disorders 49 Casecontrol study 54 Thematic interviews 56

Clinical implications and future perspectives 59 Summary of results 60 Conclusions and generated hypotheses 61 Acknowledgments 62 References 65 Appendix

iii

Abstract

Introduction The aim of the research project was to examine prevalence,

co-morbidity, and impact on daily life of pain and dysfunction in the

jawface, head, and neckshoulder regions among adult Sami women in

northern Sweden. The aim of the qualitative part of the study was to explore,

thoughts, experiences, and beliefs regarding temporomandibular disorders

(TMD) among Sami women with and without TMD, to gain insights into

their health care experiences.

Methods The research project used a mixed methods approach including

questionnaire analysis, a casecontrol study, and thematic interviews. The

study population (Papers I and III) included 487 women living in the Arctic

region of northern Sweden and enrolled in the register of the Swedish Sami

Parliament or registered as reindeer owners or reindeer herders in the

Swedish Board of Agriculture. Two years after the questionnaire study, 22

women (cases) with longstanding, intense, and frequent symptoms

indicative of TMD, together with 46 age-matched women (controls) without

any symptoms in the jaw–face region, underwent a clinical examination of

the function of the temporomandibular joint, jaw- and neck muscles,

mandibular mobility, and dental occlusion. The examiner was blind to the

women’s affiliation (Paper II). Thematic interviews with a strategic

subsample of 17 Sami women (Paper IV) were thereafter conducted and

analyzed with a grounded theory approach.

Results The prevalence of frequent symptoms indicative of TMD was 17%,

of headaches 19%, and of neckshoulder pain (NSP) 30%. Seventeen percent

reported that their TMD affected daily life. Duration of jaw pain,

troublesome impaired jaw opening, and neck pain, together with a low

education level, affected the statement of whether TMD influenced daily life

or not. Factors related to pain had the greatest influence when these Sami

women rated the related impairment. There was a statistically significant

relationship between TMD, frequent headaches, and frequent NSP (P

<0.0001). Longstanding, intense, and frequent symptoms indicative of TMD

remained essentially unchanged over the two-year follow-up period. Cases

reported impaired general health and awareness of clenching teeth

significantly more frequently than did controls. Variations in dental

occlusion did not distinguish cases from controls. In the qualitative part of

the project the core category, “Grin(d) and bear it,” summarizes the

participants’ various ways and stages of processing and handling the

interacting categories: (1) triggers, (2) strains, (3) distrust, and (4)

reconciliation with pain and/or difficulties in life. Perpetuating factors were

iv

described as mentalphysical strain and stress, and also a tooth clenching

behavior. Women without TMD expressed factors that helped them to

handle strains, reconcile, and stay healthy. They relied on helpful social

support.

Conclusion Disabling TMD, headaches, and NSP are common in Sami

women. Women with TMD commonly expressed that tooth clenching was a

familiar habit related to strains in life; they described an impaired general

state of health and distrust in the care providers’ competence and ability to

manage their problems. Women without TMD expressed confidence in their

self-efficacy and were generally less concerned with strains in their lives.

Rehabilitation strategies aiming at empowerment and improved self-efficacy

may be a successful approach in women with disabling TMD.

Keywords: epidemiology, gender, headache, indigenous, pain, qualitative, quality of life, temporomandibular disorders

v

Abbreviations

ADL activities of daily living

Ai anamnestic dysfunction index

BMI body mass index

CI confidence interval

Di clinical dysfunction index

GT grounded theory

NRS 11-point numerical rating scale

NSP neckshoulder pain

OHRQoL oral health-related quality of life

OR odds ratio

RDC/TMD Research Diagnostic Criteria for Temporomandibular

Disorders

SD standard deviation

TMD temporomandibular disorders

TMJ temporomandibular joint

vi

Populärvetenskaplig sammanfattning på svenska

(Popular science summary in Swedish)

Smärta och funktionsstörningar i käksystemet (eng. temporomandibular

disordersTMD) är vanligt förkommande i befolkningen, och ett

folkhälsoproblem associerat med ökad sjukfrånvaro, vårdkonsumtion och

inverkan på livskvalitet. Kvinnor är i majoritet bland de som drabbas av

långvariga besvär. Syftet med forskningsprojektet var att bland samiska

kvinnor, undersöka förekomst av smärta och funktionsstörningar i

käksystemet, dess samsjuklighet med huvudvärk och smärtor i

nacke/skuldror samt hur symtomen påverkade kvinnornas dagliga

aktiviteter. Studien avsåg även att utforska tankar, erfarenheter och

föreställningar om symtom i käkarna och få en inblick i kvinnornas

erfarenhet av vården av dessa tillstånd. Kvinnorna som inkluderas i studien

var folkbokförda i Kiruna eller Gällivare kommun och registrerade i 1997-års

sametingsröstlängd eller jordbrukverkets företagarregister över

renägare/renskötare. Data insamlades med hjälp av frågeformulär, klinisk

undersökning av käksystemet samt genom tematisk intervju. Totalt

besvarade 487 kvinnor mellan 21 och 70 år, enkäten som fokuserade på

förekomst av symtom från käkar, huvud, nacke/skuldror, hur ofta symtomen

förekom, under hur lång tid de haft dessa samt en skattning av symtomens

intensitet och påverkan på dagliga aktiviteter.

Frekvent (minst en gång i veckan) återkommande smärtor och

funktionsstörningar i käksystemet rapporterades av 17% av deltagarna i

enkätstudien, frekvent återkommande huvudvärk av 19% och smärta från

nacke/skuldror av 30%. Sjutton procent av samtliga kvinnor angav att

symtomen i käkarna påverkade deras dagliga liv negativt, och många av

kvinnorna hade symtom från samtliga undersökta områden, som tecken på

en samsjuklighet för tillstånden. Smärta från käkar hade störst betydelse när

kvinnorna skattade hur symtom från käkarna påverkade deras dagliga

aktiviteter, även nedsatt gapförmåga, smärta i nackregionen och låg

utbildningsnivå var av betydelse.

Alla kvinnor med långvarig, intensiv och frekvent smärta och

funktionsstörning i käksystemet erbjöds en klinisk undersökning 2 år efter

enkätstudien; 22 TMD kvinnor (fall) och 46 åldersmatchade kvinnor

(kontroller) utan några symtom från käkarna deltog. Undersökaren var

blindad dvs. visste inte vilka som var fall eller kontroller. Den kliniska

undersökningen omfattade käkled, käkmuskulatur, käkrörlighet och

bettförhållanden. Fall och kontroller hade likartade bettförhållanden. Fallen

vii

hade högre body mass index (BMI) än kontrollerna. Kvinnorna inom

fallgruppen rapporterade sämre allmän hälsa och högre medvetenhet om

tandpressningsovanor än kontrollerna.

Sjutton kvinnor från den kliniska undersökningen, varav tio kvinnor med

TMD, valdes ut till en tematisk intervju. Intervjuerna fokuserade på tre

teman, det samiska arvet, livserfarenheter, hälsa/ohälsa. Intervjuerna

analyserades med en kvalitativ metodik som kallas grounded theory.

Metoden syftar till att generera hypoteser. Analysen kom fram till

huvudkategorin ”Det är bara att bita ihop”, vilken sammanfattar deltagarnas

olika sätt och stadier av bearbetning och hantering av de samverkande

kategorierna: (1) utlösande faktorer, (2) belastning/spänningar (3)

misstro/misstrodd, och (4) förlikning med smärta och/eller svårigheter i

livet. Vidmakthållande faktorer beskrevs i termer av mentalfysisk

belastning, och stress, samt en vana av att hålla/bita ihop käken. Kvinnorna

utan TMD beskrev faktorer som hjälpte dem att hantera påfrestningar,

förlika sig med besvären, och hålla sig friska. De förlitade sig också på

omgivningens sociala stöd.

Sammanfattningsvis visar avhandlingen att smärta och funktionsstörningar i

käksystemet, huvudvärk och smärta från nacke/skuldror är vanligt

förekommande bland samiska kvinnor. Medvetenhet om tandpressning eller

att hålla ihop käkarna förknippades med belastningar/spänningar i livet,

nedsatt allmän hälsa och med symtom från käkarna. De som intervjuades

och hade symtom ifrån käkarna utryckte misstro mot vårdgivares kompetens

och möjligheter att behandla deras problem i käkarna. De kvinnor som inte

hade symtom uttryckte stark tilltro till sin egen förmåga att klara av

svårigheter och var i allmänhet mindre oroliga för påfrestningar i livet.

Behandlingsinsatser som inkluderar självbestämmande och att stärka

individens tilltro till sin egen förmåga kan vara viktiga delar för

framgångsrik behandling av kvinnor med handikappande smärtor och

käkfunktionsstörningar.

viii

Bealledieđalaš čoahkkáigeassu davvisámegillii

(abstract in North Sami)

Várka ja doaibmahehttejupmi geađaš-oalulvuogádagas (eaŋg. temporo-

mandibular disorders, TMD) lea olbmuid gaskkas dábálaš ja mielddisbuktá

váttuid álbmotdearvvašvuođa dillái ja dasa gullá bargosaji váilevaš

oassálastin, eanet dikšungeavaheapmi ja dat váikkuha olbmuid eallindillái.

Dutkanprošeavtta ulbmil leai sápmelaš nissonolbmuid gaskkas guorahallat

jus lea várka ja doaibmahehttejupmi geađaš-oalulvuogádagas, ja mo dat

doibmet ovttas iežá buohccivuođain dego oaivebákčasiin ja várkkain

niskkis/oalggis ja got dávdamearkkat váikkuhit nissoniid beaivválaš

doaimmaide. Dutkan galggai maiddái iskat jurdagiid, vásáhusaid ja

miellagovaid mat gullet dávdamearkkaide geađaš-oalulvuogádagas ja oažžut

gova nissoniid vásáhusain dikšuma hárrái dan dáfus. Nissonat geat ledje

mielde guorahallamis ledje Girona ja Jiellevári gielddaid álbmotlogus ja ledje

mielde sámedikki 1997 jagi jienastanlogus dahje eanandoallodoaimmahaga

boazodoallofitnodatlogus. Dieđut čohkkejuvvojedje jearahallanskovi bokte,

geađaš-oalulvuogádaga klinihkalaš iskama bokte ja temáhtalaš jearahallama

bokte. Oktiibuot vástidedje 487 nissona geat ledje gaskal 21 ja 70 jagi

boarrásat jearahallanskovi jearaldagaide, mas váldojearaldahkan ledje

dávdamearkkat geađaš-olloliin, oaivvis, niskkis/oalggis, man dávjá dovde

daid mearkkaid, ja man guhká dat ledje leamaš sis ja sin meroštallama

makkár váivvádusdássi leai ja mo dávdamearkkat váikkuhedje sin beaivválaš

doaimmaide.

Várka ja doaibmahehttejupmi mii dáhpáhuvai dávjá geađaš-oalulvuogádagas

(unnimusat oktii vahkus) leai 17 % sis geat oassálastet jearahallan-

guorahallamis. Dávjjes oaivebákčasa dieđihedje 19% ja várkka niskkis/

oalggis 30 %. Čiežanuppelohkái proseanta oppa nissonjoavkkus dieđihedje

ahte dávdamearkkat geađaš-oalulvuogádagas váikkuhedje sin beaivválaš

eallima negatiivvalaččat. Olu nissonat dieđihedje dávdamearkkaid juohke

guorahallojuvvon oasis, mii mearkkaša ahte buohccivuođat doibmet

oktasaččat. Várka olloliin leai deaŧaleamus go sii meroštallet mii dávda-

mearkkaid váikkuhii eanamusat sin beaivválaš doaimmaide, muhto

mearkkašupmi leai maiddái jus sis leai váilevaš njálmmi cakkastandássi,

várka niskkis/oalggis ja vuollegis oahpahusdássi. Visot nissonat geain leai

guhkálaš, garra ja dávjjes várka ja doaibmahehttejupmi geađaš-

oalulvuogádagas bovdejuvvojedje klinihkalaš guorahallamii 2 jagi maŋŋel

jearahallanguorahallama: 22 TMD nissona (ášši) ja 46 nissona geat ledje

seamma agis ja geain eai lean dávdamearkkat geađaš-oalulvuogádagas

(buohtastahtti) oassálaste.

ix

Guorahalli ieš leai diehtemeahttun goappá jovkui visses nisson gulai.

Klinihkalaš guorahallamii gulle geađaš-oalullađđasat, geađaš-oaluldeahkit,

geađaš-oalullihkadeapmi ja gáskinvejolašvuođat. Gáskinvejolašvuođat ledje

seammalágánat ášši- ja buohtastahtti-joavkkus. Nissoniin ášši-joavkkus leai

alit BMI (Body Mass Index) go buohtastahtti-joavkkus. Nissonat geat gulle

ášši-jovkui dieđihedje heajut almmolaš dearvvašvuođa ja alit diđolašvuođa

heajos bátnegaskindábiid birra go buohtastahtti-joavkku nissonat.

Čiežanuppelohkái nissona klinihkalaš guorahallamis, ja dan joavkkus logis

geas leai TMD, válljejuvvojedje njálmmálaš jearahallamii. Jearahallamiin

biddjojuvvui deaddu golmma fáddái, sápmelaš árbedillái, eallinvásáhusaide

ja (váilevaš) dearvvašvuhtii. Jearahallamat analyserejuvvojedje kvalitatiivva

vuogi mielde (mii gohčoduvvo eaŋgalasgillii Grounded theory), man vuogi

mielde sáhttá ráhkadit hypotesaid. Analiissa gávnnahii čuovvovaš

váldokategoriija “Ii leat iežá go doallat njálmmi čavga gitta (ja gierdat)”, mii

čoahkkáigeassá oasseváldiid sierralágán vugiid ja dásiid got meannudedje ja

gieđahalle oktiigullevaš kategoriijaid: (1) dili álggaheaddji (2) deaddu/

gealdagat (3) eahpeluohttámuš ja (4) várkka ja/dahje eallima váigatvuođaid

gierdan. Dili doalaheaddji fáktorat dieđihuvvojedje leat mentála-fysalaš

deaddu ja streassa, ja maiddái dáhpi gaskit/doallat njálmmi čavga gitta.

Nissoniin geain ii lean TMD dieđihedje fáktoriid mat veahkehit sin gierdat

váigatvuođaid, soabadit váivviin, ja bissut dearvvašin. Sii dorvvastedje

maiddái lagasolbmuid sosiála doarjagii.

Oppalaččat čájeha nákkosgirji ahte várka ja doaibmahehttejupmi geađaš-

oalulvuogádagas, oaivebávččas ja várka niskkis/oalggis lea dábálaš dilli

sápmelaš nissoniid gaskkas. Diđolašvuohta doallat bániid oktii dahje doallat

njálmmi čavga gitta mielddisbuvttii deattu/gealdagiid eallimii, váilevaš

almmolaš dearvvašvuođa ja dávdamearkkaid geađaš-oalulvuogádagas. Sii

guđet jearahallojuvvojedje ja geain ledje dávdamearkkat geađaš-

oalulvuogádagas dieđihedje eahpeluohttámuša sidjiide guđet doaimmahedje

dikšuma sin gelbbolašvuođa geažil ja eahpidedje maiddái sin vejolašvuođa

meannudit sin buohccedili. Nissonat geain eai lean dávdamearkkat

dieđihedje garra luohttámuša sin iežaset návccaide čoavdit sin iežaset

váttisvuođaid ja sis leai unnit ballu oažžut váttuid.

Dikšunstrategiijat mat siskkildit iešmearrideami ja mat nannejit oktonas

olbmo jáhku iežas návccaide sáhttet leat deaŧalaš oasit buori

buohccedikšumis nissoniidda geain leat várkkat mat hehttejit sin doaimmaid

ja váilevaš geađaš-oalulvuogádatdoaimmat.

Translation: Professor Mikael Svonni, UiT, The Arctic University of Norway

x

Original papers

This doctoral thesis is based on the following original papers, which will be

referred to in the text by their Roman numerals:

I. Storm C, Wänman A. Temporomandibular disorders, headaches and

neckshoulder pain among females in a Sami population. Acta Odontol

Scand 2006; 64: 319-325.

II. Storm C, Wänman A. A two-year follow-up study of temporomandibular

disorders in a female Sami population: validation of cases and controls as

predicted by questionnaire. Acta Odontol Scand 2007; 65: 341-347.

III. Mienna CS, Wänman A. Self-reported impact on daily life activities

related to temporomandibular disorders, headaches and neck-shoulder pain

among women in a Sami population living in northern Sweden. J Orofac

Pain 2012; 26: 215-224.

IV. Mienna CS, Johansson EE, Wänman A. “Grin(d) and bear it”- Narratives

from Sami women with and without temporomandibular disorders. A

qualitative study. J Orofac Pain & Headaches 2014; 28: 243-251.

The papers are reprinted with the kind permission of the publishers; Informa Healthcare, London (papers I and II), and Quintessence Publishing Company Inc, Chicago (papers III and IV).

xi

Preface

As I recall, it was a warm and sunny Easter day. I was resting on a reindeer

skin, in a snowdrift; a fire crackled, and my thoughts happened to be in the

deep woods surrounding Lake Inari in Finland. I had a break in the middle

of the 5th semester of my dental education, and my teacher in clinical oral

physiology had sent me off with a thesis, so I had “something to do during

the Easter holidays,” since the curriculum did not have any leisure, but “time

to read.” So far, it had been the most interesting course in the dental

program, and although I was still not sure about the choice of dental career,

this was while sitting on that reindeer skin that I decided to continue on with

the program. It was time to decide on a graduation project, and I believe the

teacher thought that the Helkimo study on Skolt and Inari Samis in Finland

would inspire me, since I was Sami myself. I had previously studied Sami

culture, history, and language at the University, and thought it might be a

suitable project, combining my choice of occupation with a project within a

Sami context. Easter was celebrated as usual, up in the mountains, at the

finest place I know, Rautasjaure, the birthplace of my grandparents and

ancestors. Like the Sami women who came to participate in my research, I

gather strength and energy in a place far away from modernity, such as

electricity, running water, and mobile phone coverage. Perhaps it is my Sami

heritage that raises my longing to be away from civilization at some point

every year, to find peace of mind.

Being able to finish this PhD has at times felt quite impossible, because of ill

health, which meant long periods of sick leave. Many times I have thought

that I wouldn’t manage to complete the project, but the work of this thesis

has often been a great way to dispel those thoughts, when life has been extra

tough. Illness sometimes leads to other perspectives, and I thought a lot

during those periods about how I wanted my career to develop. I decided to

study further to become a specialist in clinical oral physiology. Thus, any

interruption in the PhD program, I cannot ascribe to illness. There were also

positive events such as the three-year specialist training, and the biggest and

best event in my life, becoming a mother. I took as much maternal leave as I

possibly could.

My research started with questions about the prevalence of temporo-

mandibular disorders (TMD) in the Sami population, since the prevalence

was high in the Helkimo study compared to that of other populations.

Another perspective was related to the question why women dominate as

patients referred for treatment. Today, these patients constitute my everyday

life as a specialist. Combining the quantitative study with a qualitative

xii

approach made it possible to obtain a deeper knowledge of individuals’

experiences, in my wish to find reasons why women are more affected by

TMD than men. I believe that the answer is complex and may be found in the

biopsychosocial model. Our social context probably has a greater significance

for the way we handle things than we normally realize. Perspectives on a

condition may be widened when quantitative and qualitative research

methods are combined. In my opinion, one method is not better or worse

than the other; rather, they should be seen as complementary to each other,

and it has been educational to use both.

The cover photo is from my paradise, Rautasjaure, the mountain called

”nieidabákti” (girl mountain).

Morgonen därpå stack vi över sjön till Rimakalles sten, ett stort flyttblock,

som det inte var något annat märkvärdigt med än att jätten skulle ha

legat på den. Men vi kom rakt under Neitapaktes stup, och det var något

värt. Mästaren hade huggit hårt med mejseln däruppe; det var skarpa

drag och djupa fåror. Medan båten gled fram under stupet, undrade Lill,

varför dom kallat fjället just Neitapakte. Neita betydde ju flicka, men inte

var den där hemska bergväggen just flickaktigt. –Uppifrån fjället där vi

vaktar renarna, ser det ut på ett annat vis, svarade Lars Hova och

rodnade lätt. På vad vis då? Lars Hova hade svårt att komma fram med

svaret. Keinil log stilla, och när det äntligen blev klart, att fjällkonturen

däruppifrån påminde renskötarna om konturen av en flicka under

koltbarmen, då smittade unge Hovas rodnad av sig på den som frågade.

~ Ur boken Bortom fjällen av Ernst Manker, 1957

I hope you will enjoy this reading as much I have enjoyed writing it.

Umeå, September 2014

Christina Storm Mienna

INTRODUCTION

1

Introduction

The Sami population

The Samis are the Indigenous people in Sweden, Norway, Finland, and Kola

Peninsula in Russia. In 1977, the Swedish Parliament recognized the

indigenous status of the Sami. Since 2011 the Sami are recognized as a

people in the Swedish constitution. The Sami people have historically lived

in the region called Sápmi (Samiland), which overlaps the borders of four

nations (Figure 1).

Figure 1: Map of Sápmi. Reprinted and adjusted with permission from Nordiska museet, Stockholm.

Studies of genetic markers in the Sami people over four decades have shown

that they are genetically unique compared to other populations studied

(Beckman 1996). The relatively homogeneous genetic composition of the

Samis, combined with a shared cultural heritage, make them suitable for

studies related to development of diseases with a multifactorial background

(Johansson et al. 2005).

A detailed census of the Sami people has not taken place, as ethnic markers

are forbidden in national population registers, as regulated by Swedish laws.

It is estimated that there are about 85 000 Samis altogether, of whom

approximately 20 000 live in Sweden and of whom 2500 work full-time with

reindeer herding (Solbakk 2006). However, the Sami population in Sweden

may consist of as many as 40 00050 000 individuals, according to a

INTRODUCTION

2

constructed database on health and living conditions (Hassler et al. 2004a).

About 50% of the total Sami population in Sweden lives in the northernmost

county, Norrbotten (Sjölander 2011). For the Sami people, reindeer herding,

fishing, hunting, and handicrafts were historically traditional ways of life

(Solbakk 2006). Today most Sami participate as an integrated part in

various professions and economic activities in society. They have been

assimilated into a western lifestyle and thereby share the accompanying

diseases (Hassler et al. 2005).

Knowledge of the Sami health situation in Sweden is fairly limited, but

during the last decade several studies mainly based on data from national

registers, have been published. The Southern Lapland Research Department

in Vilhelmina has accounted for improvements in the knowledge of the Sami

people’s health situation in Sweden. Despite these efforts, Sweden is still far

behind Norway, where governmental resources have been allocated for

research on the health situation of their Indigenous people, the Samis. In

2007, the United Nations special rapporteur Paul Hunt (Hunt 2007)

recommended that the Swedish government support the establishment of a

Sami Health research centre, as in Norway; he also suggested that the

Swedish government should “consider establishing a body within the

Ministry of Health with national responsibility for oversight of Sami health”.

Hitherto, no such unit has been established in Sweden. During 2013

Västerbotten County Council applied to the Swedish government to start a

national Sami Healthcare center. If this becomes reality, related resources

may help to conduct further research on the Sami population’s health

conditions.

In general terms the health and living conditions of the Samis, in comparison

with other Indigenous peoples (Sjölander 2011), seem to be good and

essentially similar to that of the Swedish general population. Some

differences have nevertheless been observed. Cancer is the disease that has

been most thoroughly studied in the Sami population (Sjölander 2011). The

risk of developing and dying from cancer was lower among the Sami

compared to general populations in Norway, Sweden, and Finland. Plausible

explanations were lifestyle-related factors, including dietary components and

physical activity (Hassler et al. 2008a, Hassler et al. 2008b). Gender

differences in cardiovascular disease among the Sami have been reported.

Sami women showed an increased risk for mortality from subarachnoid

haemorrhage and ischemic heart diseases (Hassler et al. 2005). Among

women from reindeer-herding families, and for Sami men not involving in

reindeer herding, an increased risk of stroke has been reported. The

incidence of stroke was significantly increased for both Sami men and

women who had adopted a more westernized lifestyle (Sjölander et al.

INTRODUCTION

3

2008b). Sami women, particular those of reindeer-breeding families, were

more exposed than men to psychosocial risk factors, such as lower decision-

making latitude, social support, and intellectual discretion. Differences in

exposure to behavioral and biomedical risk factors can partly account for the

gender difference between Sami men and women (Edin-Liljegren et al.

2004). Musculoskeletal symptoms have been highly observed among both

men and women in reindeer-herding families. In men, the use of terrain

vehicles was the main cause (Daerga et al. 2004, Näyhä et al. 1991, Sjölander

et al. 2008a), with a higher risk for fatal accidents (Hassler et al. 2004b). In

women, on the other hand, the musculoskeletal symptoms seemed to be

related to psychosocial factors such as poor social support, high effort, low

reward, and high financial responsibilities.

Temporomandibular disorders

Terminology

The jaw system is essential for survival, and is involved in basic functions

such as mastication, biting, tasting, swallowing, respiration, and speech.

These functions engage the mandible, the teeth, the tongue, the cheeks, the

temporomandibular joint (TMJ), the skull, the upper part of the spinal

column, the jaw-and neck muscles, the salivary glands, the nervous system,

and blood supply. A disturbance in any of these parts may thus affect the

functions of the jaw system and the quality of life.

In 1934, an otolaryngologist, Dr. James Costen (Costen 1934), described

symptoms from around the ear and the temporomandibular joint, which he

attributed to the dental occlusion; the term Costen’s syndrome was coined.

Different ways to designate functional disturbances of the masticatory

system have since been advocated; temporomandibular joint dysfunction

syndrome, occlusomandibular disturbances, myoarthropathy of the

temporomandibular joint, myofascial pain dysfunction syndrome,

temporomandibular pain dysfunction syndrome, mandibular dysfunction,

internal derangements of the temporomandibular joint, and so on. The

different terms describe various views of the possible origin and main feature

of the condition; some focus on dysfunction and others emphasize pain.

These terms were in the 1980s included under the broader concept

craniomandibular disorders, and from the 1990s onwards the most

commonly used expression in the literature is temporomandibular disorders

(Okeson 2008).

INTRODUCTION

4

Temporomandibular disorders (TMD) is a collective term embracing a

cluster of related disorders in the masticatory system, with common

symptoms (Drangsholt and LeResche 1999) and clinical problems involving

muscles, the TMJ, the occlusion, the nervous system, and associated

structures (de Leeuw 2008). In 1983, the American Dental Association,

(Drangsholt and LeResche 1999) characterized TMD as a condition with pain

in the TMJ region and/or in the jaw muscles during function, limitation in

mandibular range of motion and/or TMJ sounds during jaw function. TMD

can be regarded as musculoskeletal disorders in the jawface region, since it

resembles other musculoskeletal disorders and chronic pain conditions.

Classification

Different systems have been advocated over the years to classify signs and

symptoms of TMD in attempts to systematically standardize definitions for

classifying or stating a diagnosis of TMD conditions (Fricton and Schiffman

1986, Lundeen et al. 1986, Dworkin and LeResche 1992,). In my doctoral

thesis two models for classification of TMD were used; the anamnestic (Ai)

and clinical dysfunction (Di) indices as devised by Helkimo (Helkimo 1974b)

and the Research Diagnostic Criteria for Temporomandibular Disorders

(RDC/TMD) (Dworkin and LeResche 1992). The anamnestic dysfunction

index was developed to classify reported symptoms in three grades based on

expected severity: Ai 0 = symptom-free, Ai I = mild symptoms (jaw tiredness

and TMJ sounds), and A II = severe symptoms (TMJ locking, difficulties in

opening wide and jaw pain). The clinical dysfunction index was based on the

outcome of a clinical examination that measures range of mandibular

movement, function of the temporomandibular joint, presence of pain on

movements of the mandible, presence of muscle pain, and/or

temporomandibular joint pain to palpation. Each variable examined is

scored on three levels of severity based on defined criteria: no signs of

dysfunction (0 points), mild signs of dysfunction (1 point), and severe signs

0f dysfunction (5 points). The sum of the scores can thus range from 0 to 25

points. The index is constructed as an ordinal scale in four grades of severity:

no signs of dysfunction (Di 0), mild signs of dysfunction (14 points, Di I),

moderate signs of dysfunction (59 points, Di II), and severe signs of

dysfunction (1025 points, Di III).

RDC/TMD was developed for clinical and epidemiological research purposes

to provide standardized diagnostic classifications of the most common TMD

conditions (Dworkin and LeResche 1992). Axis I is a non-hierarchical

diagnostic scheme, and a condition can be diagnosed into one of three main

groups: (1) muscle disorders (2) disc displacements, and (3) arthralgia,

arthritis, and arthrosis. The RDC/TMD Axis II classification system included

INTRODUCTION

5

pain-related disability and psychological status (Dworkin and LeResche

1992). The classification system has recently been revised to Diagnostic

Criteria of TMD (DC/TMD), aimed for clinical use (Schiffman et al. 2014).

Etiology

The etiology of TMD is complex and, multifactorial, and has been debated

over the years. One more recently advocated perspective is summarized in a

biopsychosocial model (Suvinen et al. 2005). Parker presented in 1990 a

dynamic model to depict the etiology. He proposed that there was a balance

in the masticatory system between destructive, overloading factors and

adaptive factors. Factors such as trauma, health/nutrition, the

musculoskeletal structure, coping strategies, and gender might increase or

decrease a patient’s adaptability. Life stressors, sleep disorders,

pain/depression, occlusion, and posture were proposed as predisposing

factors to dysfunction (Parker 1990).

Structural damage of the TMJ has also been proposed, because it changes

physical properties and may alter the ability to withstand loading forces

(Stegenga et al. 1991). In a similar perspective on the etiology of TMD, the

balance between load and capacity of the involved structures has been

advocated (Wänman and Agerberg 1991). Since no single factor has been

identified as a sufficient or necessary etiological factor, it may be more

relevant to describe them as contributing factors (De Boever and Carlsson

1994). These contributing factors have been classified as predisposing,

initiating, and perpetuating. Those that increase the risk of developing TMD

are regarded as predisposing factors, and it has been proposed that they be

subdivided into systemic (e.g. inflammatory or degenerative diseases);

psychological, such as personality, behavior, and mood disturbances; and

structural, such as different types of occlusal discrepancies and joint laxity.

Initiation factors are those that induce onset of TMD, and such proposed

factors are micro and macro trauma, and adverse or excessive loading of

joint structures, including parafunctions such as bruxism (De Boever and

Carlsson 1994). Factors that interfere with healing or enhance the

progression of TMD are referred to as perpetuating factors, which may be

divided into local (parafunctions and posture) and systemic such as

behavioral, social, emotional and cognitive factors (De Boever and Carlsson

1994, Okeson 2008). Occlusal factors, such as mandibular instability, and

cross bite have been reported as possible candidates in relation to

perpetuation of TMD (Kirveskari and Alanen 1984, De Boever et al. 2000,

Marklund and Wänman 2010a). Conflicting results exist regarding the

importance of dental occlusion in relation to the etiology of TMD. In a review

(Türp and Schindler 2012), bruxism, loss of posterior support, and unilateral

INTRODUCTION

6

posterior cross bite showed some possible relationship to TMD, but the

authors also pointed out that disturbances in the occlusion may be a

consequence of TMD and not its cause. In a recent study, the authors

concluded that malocclusion and loss of five or more posterior teeth did not

contribute to TMD (Sousa et al. 2014).

It is likely that many conditions can affect the function of the jaw system and

the individual response also depends on several factors that make research

in etiology both difficult and demanding.

Epidemiology

Epidemiological methods can be used to identify how common a condition is

in a population as well as its natural course if it is left untreated, and to

assess risk factors for onset and perpetuation. Cross-sectional studies based

on representative samples of a population are usually conducted to

determine the prevalence of the problem in focus. Prevalence is defined as

the number of persons with the condition at a specific time divided by the

total size of that population. Knowledge of the prevalence can help to

determine the magnitude of a health problem and its burden on the

individual and the society (Drangsholt and LeResche 1999).

Early clinical studies of TMD indicated that it is a common, heterogeneous

pain disorder, primarily afflicting women aged 2045 years (Helkimo 1976).

In 1972, the first epidemiological study of dysfunction of the masticatory

system was published (Helkimo et al. 1972). Helkimo performed a cross-

sectional study on 245 Skolt- and 76 Inari-Lapps in the north of Finland and

used the Ai and Di indices for descriptive purposes (Helkimo 1974b). He

observed that signs and symptoms of mandibular dysfunction were common

in this Sami population; 88% had one or more signs and 57% had symptoms

of mandibular dysfunction. He estimated that approximately 25% of this

population had need for treatment, since 22% had severe signs and 26% had

severe symptoms according to the indices (Helkimo 1974a). Despite a large

number of subsequent studies in different populations, none has since

reached the high prevalence found in Helkimo’s study on a Sami population

in Finland. Partly from this perspective it was interesting to conduct a new

study on a Sami population.

The prevalence of TMD signs and symptoms varies, depending on

methodology and population (Nydell et al. 1994). A review from 1984,

arrived at a median value of one out of three for TMD symptoms and two out

of three for TMD signs and found a large variation between different studies

(Carlsson 1984). The prevalence of TMD symptoms was 20% and 50% had

INTRODUCTION

7

TMD signs in a Dutch population (De Kanter et al. 1993). Salonen et al.

reported similar results based on a Swedish population (Salonen et al. 1990).

Jagger et al. reported a prevalence of TMD in an indigenous Ecuadorian

population similar to that of Scandinavian samples (Jagger et al. 2004). An

increase in prevalence of symptoms indicative of TMD during a 20-year

period has been observed (Anastassaki et al. 2012). It has been proposed that

psychosocial health determinants are involved in the observed time trend

(Anastassaki and Magnusson 2004). In a review of TMD pain, approximately

one out of three adults was predicted to develop TMD pain during their

lifetime (Drangsholt and LeResche 1999).

The prevalence of severe TMD symptoms is rare in young individuals

(Anastassaki et al. 2009), but increases during the adolescent period

(Nilsson et al. 2009). Longitudinal studies have shown that both signs and

symptoms of TMD fluctuate over time (Magnusson et al. 1985, Wänman

1987, Könönen and Nyström 1993, Marklund and Wänman 2010a). Several

population-based studies on TMD pain and headaches have observed a

declining prevalence with age (Salonen et al. 1990, Österberg and Carlsson

2007, Carlsson et al. 2014,), with older individuals reporting TMD symptoms

less often than younger ones. The reason behind this observation is not

known. In a sample of 90-year-olds, signs and symptoms of TMD were

predominately of mild character and infrequent, except for TMJ crepitation

(Tzakis et al. 1994). In a cross-sectional study including 70- and 80-year-

olds, 6-10%, reported some, and 1-2% rather great or severe problems of

TMD pain (Carlsson et al. 2014). TMD symptoms were also rarely reported

among another sample of 70-year-olds (Österberg and Carlsson 2007). In a

recent population-based study the prevalence of frequent symptoms

indicative of TMD peaked among 50-year-old women and then declined in

the more elderly women (Yekkalam and Wänman 2014a). Johansson et al.,

on the other hand, reported no differences in prevalence of TMD symptoms

between 50 and 60 years of age in a 10-year follow-up study (Johansson et

al. 2003).

Gender differences

It has generally been reported that women have more signs and symptoms of

TMD than men, but no major difference in the prevalence of mandibular

dysfunction was found between men and women in the Sami population in

northern Finland. Only a few symptoms differed in prevalence with gender,

with significantly higher prevalence of headache, NSP and feelings of fatigue

in the jaws in Sami women (Helkimo 1974c).

INTRODUCTION

8

Cross-sectional studies on samples from general populations have found

varying proportions of men and women relative to prevalence of TMD. One

reason may be related to inclusion criteria of symptomstheir frequency,

intensity, and duration. Among patients with TMD, women outnumber men,

with more women seeking treatment and being referred to consultants. For

referrals to specialist TMD clinics, commonly reported ratios of women-to-

men are 3:1, and the majority of patients are between 20 and 40 years of age

(Anastassaki and Magnusson 2004). In a sample drawn from the general

population, 50-year-old women reported significant higher prevalence of

symptoms indicative of TMD than men of the same age, no gender

differences were found in 65- to 75-year-olds (Yekkalam and Wänman

2014a). In a prospective study over approximately 10 years, women showed a

longer duration of TMD symptoms compared to men (Wänman 1996).

Different courses of TMD symptoms between men and women indicate that

women may be less likely to recover from these conditions, although

fluctuations of symptoms occurred among both men and women during the

observation period. Other differences in the TMD symptom’s quality, such as

its frequency, intensity, and effect on quality of life, may also be factors of

importance related to utilization of health care.

Sex-related differences have been observed in both clinical and

experimentally induced pain studies (Fillingim 2000). In a review, of gender

variations in pain experience (Unruh 1996), it was suggested that women are

more likely than men to experience a variety of recurrent pains. Women

report more severe pain levels, more frequent pain, and pain of longer

duration than men do. Women may also be at greater risk for pain-related

disability than men. Gender variation in coping strategies was also found. It

has been suggested that women develop coping strategies that include active

behavioral and cognitive coping, avoidance, emotion-focused coping, seeking

social support, relaxation, and distraction. Men instead seem to use

strategies including talking problems down, denial, looking on the bright

side of life, and tension-reducing activities such as alcohol consumption,

smoking, and drug abuse. Gender differences in brain chemistry,

metabolism, physical structures, and hormone variations may influence the

biological mechanisms of pain transmission, sensitivity, and perception.

Sociological and psychological factors, culture, and ethnicity may also

influence pain perception and behavior. Women with multiple

responsibilities such as childcare, household management, and full or part-

time employment may have more than one reason to apprehend pain as a

threatening condition. Men may perceive pain as being of limited

importance unless it interferes with their work. These factors may be

important in understanding pain and disability in a population, and since

there may be gender-related influences of TMD, it has been proposed that

INTRODUCTION

9

men and women should be studied separately in research of contributing

factors to TMD (Wänman 1996, Henrikson 1999,). Women and men may

also differ in their recovery from pain and may therefore require different

interventions (Unruh 1996).

Co-morbidity

Several studies have demonstrated co-morbidity between TMD, headaches,

NSP, and back pain. (Schokker et al. 1990, Ciancaglini and Radaelli 2001,

Visscher et al. 2001b, Rantala et al. 2003, Wiesinger et al. 2007,). Headache

is a common condition in the population and has been associated with signs

and symptoms of TMD (Wänman and Agerberg 1987, Cooper and Kleinberg

2009, Marklund et al. 2014,). Headaches are more commonly reported by

women than by men after childhood (Rasmussen et al. 1991). There is a

relationship between TMD and muscle tenderness. In an epidemiological

study of 35-year-olds the subjects were grouped according to patterns of

muscle pain to palpation. Those who had tender sites to palpation at both

neck and jaw muscles, together with those who showed a pattern of more

generalized hyperalgesia, had significantly higher prevalence of signs and

symptoms of TMD than other groups (Wänman 1995). In addition to the

relationship between pain in jaw and neck muscles, there is also a functional

relationship between these regions. Thus, during jaw function such as

opening and closing, an integrated pattern between the jaw and head

movements has been observed (Eriksson et al. 1998, Eriksson et al. 2000).

Individuals with symptoms of TMD have also in several studies reported

impaired general health status (Agerberg and Carlsson 1975, Johansson et al.

2004, Österberg and Carlsson 2007, Carlsson et al. 2014). Central and

peripheral sensitization mechanisms are involved in pain perception (Sarlani

et al. 2004) and may induce spread of pain to the jawface area from other

regions, such as back, chest, and stomach. (John et al. 2003). Stimulation of

either the trigeminal or the spinal area affects the other, as has been shown

in experimental pain studies (Hellström et al. 2000, Komiyama et al. 2005).

Taken together, these findings indicate that pain and dysfunction in the jaws,

head, neck, and shoulders may influence each other and/or share the same

contributing factors.

Consequences

It has been proposed that TMD pain is related to social factors such as

unemployment and decreased work effectiveness (Drangsholt and LeResche

1999), and that individuals with chronic TMD pain had burdens, for society

and the individual, similar to those of people with back pain, severe

headache, and chest and abdominal pain, including psychological distress

INTRODUCTION

10

and, economic costs for society and the patient (Drangsholt and LeResche

1999). Other studies have shown negative consequences for individuals, such

as having spent a lot of money for treatment, or lost their jobs, and even

their houses and belongings (Garro et al. 1994). The costs for society due to

TMD pain include costs of providing care and costs associated with work loss

and decreased productivity of work. In a study from Finland a sample, drawn

from keyboard operators in an industry with NSP, were randomly referred to

either a treatment or a non-treatment group. The treatment was directed

towards stabilization of the mandible, with selective tooth grinding, and in

some cases, bite-splints. Both groups averaged 33 days of sick leave the year

before the study started. One year after, the treatment group showed an

average reduction of 11 days, while the non-treatment group had a slight

increase of sick-leave days (Kirveskari and Alanen 1984). In a review

(Dahlström and Carlsson 2010) it was shown that oral health-related quality

of life (OHRQoL) was negatively affected among TMD patients. Studies on

TMD are from this point of view important for both the individuals and for

society.

Mixed methods

A combination of quantitative and qualitative methodology can give new

perspectives from both approaches. Epidemiological studies with a

quantitative approach can add knowledge about incidence, prevalence,

natural history of diseases, and determinants. To capture a deeper

understanding about experiences, attitudes, norms, knowledge, and

behavior, qualitative approaches are more suited. Qualitative studies are

rooted in traditions from the disciplines of anthropology, sociology, and

psychology (Polit and Beck 2006). One commonly used description of a

qualitative approach is “an inquiry process of understanding based on

distinct methodological traditions of inquiry that explores a social or

human problem. The researcher builds a complex, holistic picture, analyses

words, reports detailed views of informants and conducts the study in a

natural setting” (Creswell 1998). Three basic types of mixed method designs

are described: convergent, sequential, and embedded. These are termed

differently by different authors, but the main procedures are equivalent

(Creswell 2003, Klassen et al. 2012, Zhang and Creswell 2013). This thesis

has used a sequential design where collection and analysis of the quantitative

data was followed by the collection and analysis of the qualitative data, to

elaborate on and expand the findings of one method with another. There are

different tools for collecting qualitative information, such as in-depth

interviews, observations, and focus group discussions. In this thesis

interviews were used to collect qualitative data.

INTRODUCTION

11

Grounded theory

Grounded theory (GT), a common method mostly used for designing and

analyzing of qualitative data, was used in this thesis. The method was

developed in sociology during the late 1960s (Glaser and Strauss 1967), with

its theoretical roots in symbolic interactionism, a social psychological

perspective where the society is regarded as a sum of all ongoing interactions

and events, and a process that is constantly changing and not a permanent

structure. It is thus process-oriented, as reality is considered to be fluid and

constantly created and modified (Morse 1992). The goal in GT is to generate

comprehensive explanations of phenomena that are grounded in reality

(Polit and Beck 2006), to generate a theory that explains a pattern relevant

to the participants involved in the study. Key features of doing GT are an

emergent design and constant comparisons (Dahlgren et al. 2004).

Trustworthiness in qualitative research

The criteria of trustworthiness in qualitative and quantitative research

capture similarities between the traditions, but have different terms because

of differences in applications and interpretations, as indicated below.

Credibility refers to the ability to capture the multiple realities of those

under study. In quantitative research the related term is internal validity,

which refers to the ability to capture the truth value (have you measured

what you meant to measure?).

Transferability refers to whether the knowledge can be transferred to other

contexts. The knowledge gained from a developed theory should fit different

scenarios that may occur in larger populations. The term for the same issue

in quantitative research is external validity, or ability to generalize (how

applicable are the results to other contexts?).

Dependability refers to the ability of the researcher to account for constantly

changing conditions of the phenomenon under study, for the interaction

with the participants, and for the emergent designed process. The term in

quantitative research is reliability, and it refers to, whether the research

result can be replicated in the same context with the same sample.

Confirmability refers to neutrality of the data rather than neutrality of the

researcher. In qualitative research the interaction between the researcher

and the participant is important, and a basis for credibility. The related term

in qualitative research, objectivity, or neutrality refers to the ability to have

INTRODUCTION

12

distance from the observed phenomenon, to be objective and to not impose

any effect on the study related to personal interests.

GT criteria for trustworthiness are somewhat different (Glaser and Strauss

1967), and are termed fitness, workability, relevance, and modifiability,

meaning that a theory fits when the categories fit the data and a theory

works when it is able to explain what is happening in reality or at a

conceptual level. A theory has relevance when the core problem according to

the informant is interpreted in natural ways, as in GT. A theory can be

changed in response to a changing world; it is in that way modifiable

(Dahlgren et al. 2004).

Rationale

The high prevalence of TMD signs and symptoms, together with a

predominantly fluctuating pattern of the condition, has called into question

the validity of epidemiological findings. From the clinical perspective,

women outnumber men as patients for these disturbances; the reasons for

this globally found pattern are not completely understood. It is essential not

to rely solely on patient samples when examining the associated and

contributing factors of a certain disease, because various elements may

influence a patient’s decision to seek health care. Therefore, samples drawn

from the general population are needed, not only to determine the

prevalence or incidence of a certain condition in a population, but also to

explore possible co-morbidities and relationships. Since pain and

dysfunction in the jawface/headneck region may be related to gender, it

has been proposed that men and women should be studied separately in

research of etiology. Gender, biological and psychological factors, culture,

and ethnicity may also influence pain perception and behavior and are

important in the understanding of pain and disability in a population. A

qualitative approach can help to get deeper insight in individual’s

experiences and thoughts about having longstanding dysfunction and pain

symptoms.

AIMS

13

Aims

The overall objective of this thesis was to investigate prevalence of signs and

symptoms indicative of TMD and factors related to perpetuation of

dysfunction and pain in the jawface, head, neckshoulder region and its

impact on well-being in a defined population of Sami women. The aim was

also to gain deeper insight into experiences, attitudes, and beliefs among

women with longstanding TMD.

Specific aims:

Paper I:

- To study the prevalence, frequency, intensity, duration and co-morbidity of

symptoms indicative of TMD, headaches, and neck-shoulder pain in a

defined population of Sami women.

Paper II:

- To validate self-reported longstanding, intense, and frequent symptoms of

pain and dysfunction in the jaw-face region in relation to RDC/TMD

diagnosis and clinical signs of dysfunction at a two-year follow-up.

- To compare women with TMD (cases) to women without TMD (controls)

with regard to dental occlusion, general health, and awareness of oral

parafunctions.

Paper III:

- To examine the influence of frequency, intensity, and duration of TMD,

headaches, and neckshoulder pain on activities of daily living (ADL).

- To analyze symptoms indicative of TMD, headaches, and NSP in relation to

age.

Paper IV:

- To explore thoughts, experiences, and beliefs regarding TMD among Sami

women with and without TMD.

- To gain insight into Sami women’s health care experiences.

- To generate hypotheses regarding factors associated with longstanding

TMD.

STUDY POPULATION & METHODS

14

Study population and methods

This doctoral thesis is based on three sub-studies, published in four papers.

To achieve the overall aim of the study a mixed methods approach was used.

Two papers are cross-sectional epidemiological studies, based on the

subjects’ response to a questionnaire (Papers I and III). Paper II is a

prospective casecontrol study based on a sub-sample of the former

epidemiological sample including a blinded clinical examination. Paper IV is

based on a qualitative method with thematic interviews using a grounded

theory approach on a strategic selected sample drawn from the study of

Paper II (Table 1). A flowchart over the study populations is presented in

Figure 2.

Table 1. Brief presentation of the study population and methods used.

Paper I Paper II Paper III Paper IV

Study design Cross-sectional

observational study

2-year prospective,

age-matched,

case and control study

Cross-sectional

observational study

Qualitative study

Data collection Questionnaire

Questionnaire and

blinded clinical

examination

Questionnaire

Thematic

interviews,

audio-taped

Sample

characteristics

Sami women aged

2170 years

in Sweden (n = 487)

Sami women with

(n = 22) and without

(n = 46) longstanding

symptoms indicative

of TMD

Sami women aged

2170 years

in Sweden

(n = 487)

17 informants

drawn

strategically from

Paper II

Data analysis Binary logistic

regression

(MantelHaenszel

estimates of odds

ratio)

Chi-square test,

Fisher’s exact test,

t-test, Wilcoxon’s

signed matched test,

binary logistic

regression

Multiple logistic

regression,

chi-square test

Transcribed

textfiles,

analysis based on

grounded theory


15

Figure 2: Flowchart over the study populations. NRS=11-point numerical rating scale,

NSP=neckshoulder pain, TMD=temporomandibular disorders, n.s=non significant.

Study population

Papers I and III

The inclusion criteria for the questionnaire study were women living in the

communities of Kiruna or Gällivare, in the county of Norrbotten, in the

Arctic region of Sweden. To be included they had to be registered in the

electoral register of the Swedish Sami Parliament for 1997, or in the register

of the Swedish Board of Agriculture as reindeer owners or reindeer herders.

In the electoral register from 1997, 5991 individuals were registered

compared to 8322 individuals in the register from 2013. The electoral

participation has decreased from 63% (1997) to 54% (2013).


16

The Sami Parliament Act (SFS1992:1433, Sametingslagen), states the criteria

a person must meet to have the right to vote in the Sami Parliament of

Sweden:

any person who considers themselves to be Sami; and

uses or has used the Sami language at home, or

can show that one of his or her parents or grandparents uses or used the Sami language at home, or

has a parent who is or has been listed in the electoral register of the Sami Parliament

At the time of the data selection (year 2000) the women included in the

study were between 21 and 70 years of age. The Southern Lapland Research

Department in Vilhelmina assisted in defining and selecting the sample. A

total of 751 Sami women fulfilled the inclusion criteria and were sent a

questionnaire.

Respondents and dropouts

Altogether, 487 females (65%) responded and returned the questionnaire.

Their mean age was 40.2 years (SD 12.9). In total, nine questionnaires were

returned undelivered, one because the respondent had deceased, and a

further twelve were returned blank (Table 2).

Dropout analysis

Out of those individuals who did not participate, every third one in each 10-

year age-cluster, was selected for a dropout analysis. A total of 53 women

were contacted for an interview by telephone, of whom 30 women agreed to

answer a few selected questions from the questionnaire. The most common

reasons given for not participating were “out of principle” (38%) and “for no

particular reason” (25%). Other answers were that they “had no time to fill

out the questionnaire” (11%), did not consider themselves to be Sami (9%),

had been away from their home address (8%), felt the study was

discriminatory (4%), had no symptoms (4%) or were severely ill (2%).

The prevalence of symptoms of TMD among the drop-out sample was 33%

and two out of three reported NSP. No significant differences in prevalence

of the symptoms examined were found between the dropouts and the

participants (Table 2).


17

Table 2. Number of sample, participants and dropouts among Sami women in different age group.

2130

yrs

3140

yrs

4150

yrs

5160

yrs

6170

yrs

Total

Sample 116 168 176 169 122 751

Unknown 1 4 1 3 9

Deceased 1 1

Returned blank 3 4 5 12

Participants 82 116 117 105 67 487

Dropouts 34 48 54 59 47 242

Dropout sample 11 16 17 19 15 78

Contacted 9 8 12 16 8 53

Phone interview 6 6 7 7 4 30

Paper II

For the follow-up study after two years, a sample of “cases” and “controls”

was selected based on the answers from the first questionnaire. This study

included 68 women between 23 and 72 years old.

TMD cases

The inclusion criteria to be identified as a case were, symptoms indicative of

TMD, with a frequency of at least once a week, intensity level of 5 or more on

an 11-point numerical rating scale (NRS), and a duration of at least one year.

They should also have considered themselves to be Sami, in a specific

question addressing that topic. A total of 35 women fulfilled the inclusion

criteria and of these 18 women agreed to participate. In the oldest age group

(6372 years old), only one woman fulfilled the inclusion criteria. Therefore,

to ensure that older ages also were represented, all women in this age group

with symptoms indicative of TMD, and with a frequency of once a week or

more and duration of at least one year, were included. Another five women

fulfilled these inclusion criteria of whom four agreed to participate. One

reported an intensity level of 8 on the NRS, two reported NRS 3, and one

woman reported daily pains and feelings of tiredness in the jaws and a

duration of more than 5 years, but had not filled in any intensity level on the

questionnaire. The study thus included 22 Sami women classified as “cases”.


18

Controls

The criteria to be included as a “control” were that they considered

themselves to be Sami, but did not report in the questionnaire any symptoms

indicative of TMD or pain in the neck- or shoulder region. In total, 127

women fulfilled these inclusion criteria. The women were stratified into five

age strata based on the base-line questionnaire (2130, 3140, 4150, 5160,

and 61-70 years old). The oldest age-group comprised 28 individuals of

whom 12 accepted participation, and the youngest age-groups comprised 16

individuals of whom four agreed to participate. In the other age-groups 16

women in each 10-year cluster were randomly selected. In total, 30 women

in this group agreed to participate. The control group thus comprised 46

women.

Dropouts

The non-participating cases included ten women who had moved from the

region, six women were not interested in participating, and one who was

severely ill. The drop-outs from controls included, from the oldest age

groups, seven women who did not want to be examined, four who could not

be reached or traced, three who had no possibility of travelling to the dental

clinic, one who had recently had a stroke with complications in locomotion,

and one who was away from home. In the youngest sample, seven could not

be reached or traced, and another five had moved. In the other age-groups

ten subjects could not be reached or traced, four did not want to participate,

two had moved, one could not travel to the clinic, and one had deceased.

Paper IV

For the qualitative thematic interview a purposive sample of informants with

severe TMD as well as a sample without TMD was selected. The selection of

informants was based on the answers in the two consecutive questionnaires

and the outcome of the clinical examination.

Informants with severe TMD had persistent, longstanding, frequently

occurring symptoms of TMD, with a reported intensity of 5 or more (NRS)

for at least one symptom and with clinical signs confirming a diagnosis of

TMD according to RDC/TMD. The other informants had no signs or

symptoms of TMD. The women were informed at the clinical examination

that they could be contacted again for an interview study. All of them agreed

to be contacted.


19

Informants

In total 17 women participated in the thematic interviews. The social

situation among the informants was not homogeneous regarding education

level (comprehensive school to university), family situation (single to six

family members) or working conditions (retired, unemployed, student, full-

time worker). The characteristics regarding age, symptoms and diagnosis

among the TMD informants are presented in Table 3.

Table 3. TMD informants’ age, symptoms, the symptoms stated impact on activities of daily

living (ADL) with an 11-point numerical rating scale (NRS) and, clinical diagnosis according

to RDC/TMD classification.

Age Symptoms in the

jawface (ADL)

Other cephalic

symptoms (ADL)

NSP

(ADL)

Diagnosis

RDC/TMD

Ai Di

58 Jaw pain, jaw tiredness,

TMJ sounds and locking

(5)

Headache (8)

Tinnitus (5)

Neck &

Shoulder (9)

Myalgia

Arthralgia

Arthrosis

DDwR

2 3

54 Jaw tiredness, TMJ

sounds (3)

Headache (10)

Tinnitus (2)

Neck &

Shoulder

(10)

Myalgia 1 2


TMJ sounds (*)

Headache (3)

Tinnitus (5)

Shoulder (5) DDwR 2 1


TMJ sounds (7)

Headache (9)

Tinnitus (6)

Neck &

Shoulder (9)

Myalgia 2 2

42 Jaw pain, TMJ sounds,

jaw impairment (3)

Headache (5) Neck &

Shoulder (3)

Myalgia

DDwR

2 2


TMJ sounds, jaw

impairment (7)

Headache (6)

Tinnitus (8)

Neck &

Shoulder (7)

Myalgia

DDwR

2 2

36 Jaw pain, TMJ sounds (1) Headache (3)

Tinnitus (3)

Neck &

Shoulder (3)

Myalgia 2 2


TMJ sounds, jaw

impairment (5)

Headache (8) Neck &

Shoulder (8)

Myalgia

DDwR

2 2


TMJ sounds and locking,

jaw impairment (6)

Headache (8)

Tinnitus (2)

Neck &

Shoulder (6)

Myalgia

DDwR

2 2


TMJ sounds, jaw

impairment (4)

Headache (0)

Tinnitus (2)

Neck &

Shoulder (6)

DDwR 2 1

TMD=temporomandibular disorders, RDC/TMD=Research diagnostic criteria for TMD, NSP=neckshoulder pain, DDwR=disc displacement with reduction, Ai=anamnestic dysfunction index, Di=clinical dysfunction index, *=missing.


20

Methods

Questionnaire (Paper I and III)

A questionnaire concerning symptoms indicative of TMD, headaches, and

NSP was sent to each woman’s home address, together with information and

a pre-paid return envelope. The questionnaire focused on questions

regarding frequency, duration, and intensity of the symptoms, and their

impact on daily life (Appendix I). Seven weeks after the first letter had been

sent, a reminder, along with a questionnaire, was sent to those who had not

responded, and after a further four weeks a second reminder was sent out.

Frequency: Each question on symptoms had six possible response

alternatives describing frequency: Never; No, not now but had it previously;

Yes, at most once or twice a month; Yes, once a week; Yes, several times a

week; Yes, daily. “Frequent symptom” was defined as a reported frequency of

once a week or more.

Duration: To describe the duration, each symptom had four alternatives:

less than 1 month; 1 month to 1 year; 1 year to 5 years; more than 5 years.

“Longstanding symptom” was in this study defined as a reported duration of

one year or longer.

Intensity: The intensity of symptoms was measured on an 11-point

numerical rating scale (NRS).

Impact on activities on daily living (ADL): The impact of symptoms on ADL

was measured by NRS; scales addressed headaches and NSP, respectively,

and symptoms of TMD as a group.

Symptoms of pain and dysfunction in the jawface region were grouped in

accordance with the index Ai devised by Helkimo.

The questionnaire also included open-ended questions regarding health care

utilization, which are not included in the present thesis.

Clinical examination (Paper II)

A follow-up was conducted two years after the primary investigation. This

included the same questionnaire as previously used, with a few additional

questions and a clinical examination. Sixty-eight Sami women were invited

to the clinical examination free of charge at one of the dental clinics in

Karesuando, Kiruna, or Gällivare. Participants’ expenses for travel to and


21

from the clinic were reimbursed. A standardized clinical examination was

performed by a specialist in TMD/orofacial pain who was blinded to the

participants’ affiliation as a case or a control. The examination included:

Dental occlusion: Number of teeth (032)

Overjet and overbite to the nearest mm

Contact pattern in centric relation (unilateral or bilateral)

Slide in centric in anteriorposterior, vertical, and lateral directions

to the nearest 0.5 mm

Tooth contact patterns at 3 mm and 9 mm lateral excursion of the

mandible (anterior guidance, cuspid guidance, group function,

balanced occlusion, laterotrusive side interference, mediotrusive

side interference)

Number of occluding pairs of teeth in intercuspal contact position

(ICP), at light and hard clenching effort

Supporting occlusal zones in accordance with Eichner (Eichner 1955,

Österberg and Landt 1976), without removable dentures

Presence of implant-supported fixed dental prosthesis

Degree of tooth wear Registered in accordance to Oilo (Oilo et al. 1987)

Mandibular mobility Unassisted maximal opening, protrusion, and laterotrusion

measured to the nearest millimeter with a ruler (Agerberg 1974)

TMJ signs TMJ sounds. Auscultation, without a stethoscope, for the presence of

TMJ sounds on opening and closing movements of the jaw. The

occurrence of sounds was classified as sharp clicking, dull clicking,

or crepitating.

TMJ tenderness. The TMJ was palpated laterally and posteriorly

through the auditory meatus. Pain was registered only if the

palpation elicited a palpebral reflex in the eye or a protective reflex

(withdrawal).

TMJ pain on unassisted jaw movements (opening wide,

laterotrusion, protrusion)

TMJ loading. The subject was asked to bite hard for 30 seconds on a

double wooden spatula (3 mm) placed on the region of the first

molars, each side separately. Elicited pain in the contralateral side of

the joint was registered as TMJ load pain.


22

TMJ joint play. The examiner’s first finger on the right hand was

placed on the participants’ left molar region. While holding the

mandible, it was pulled forwards and backwards with the operator’s

third finger on the left hand placed over the left TMJ. The TMJ

movement was registered if restricted, painful, or both. The

procedure was repeated on the other side.

Muscle signs

Muscle tenderness. Presence of pain to palpation of muscle sites.

Pain was registered only if the palpation elicited a palpebral reflex in

the eye or a protective reflex (withdrawal). The following sites were

palpated: region of the lateral pterygoid muscles, medial pterygoid

muscles, anterior and posterior parts of temporal muscles, tendon of

the temporal muscles, superficial and deep parts of masseter

muscles, sternocleidomastoid muscles, trapezius muscles, neck

muscles in the region of linea nuchae and thumb muscles. If the

latter elicited a pain response, the muscles on the underside of the

forearms and the calf muscles were also palpated to measure signs of

a generalized pain response (hyperalgesia) to palpation.

Static loading of jaw muscles. The participant was asked to clench

her teeth hard in the intercuspal position for 30 seconds.

Development of feeling of tiredness/fatigue or pain in the head, face,

or jaws during clenching was registered.

Perception thresholds The perception over the areas innervated by the trigeminal nerve

was tested with von Frey filaments. The following areas were tested

on the right- and left-hand sides: the forehead, the infraorbital

region, the cheek, the mental region, and the temple.

Body Mass Index (BMI) Weight and height for calculating the BMI.

Some of the variables collected in the questionnaire and some of the

variables registered clinically were used to calculate the anamnestic

dysfunction index (Ai) and the clinical dysfunction index (Di), respectively

(Helkimo 1974b). A classification of each participant was also done in

accordance to RDC/TMD Axis I (Dworkin and LeResche 1992).


23

Statistical methods (Papers I-III)

The questionnaire data were first transferred into a data-base (EpiInfo) and

then converted into SPSS ver. 12.0 (Paper I) ver. 14.0 (Paper II) ver. 17.0

(Paper III) for Windows. The level of statistical significance was set to a P-

value <0.05 (Papers IIII).

Paper I

Binary logistic regression by MantelHaenszel estimates of odds ratio (OR)

and 95% confidence interval (CI) were used.

Paper II

Comparisons between cases and controls with regard to categorical variables

were done using the chi-square test or Fisher’s exact test if the expected

counts were less than 5. Comparisons between groups with regard to

continuous variables were done using the t-test for independent samples.

Comparisons of registrations within cases and controls at the first and

second examination were done using Wilcoxon’s signed matched test.

Associations were assessed by means of ORs in unconditional logistic

regression models.

Paper III

Multiple logistic regression analysis was used to test the impact on daily life

with regard to frequency, intensity, and duration of TMD symptoms,

headaches, and NSP, together with age and education.

The dependent variable; answers on the ADL scale for TMD was

dichotomized into those who stated 0 and those who stated ≥1 for the

regression analysis. Answers on the ADL scale for headaches and neck or

shoulder pain were dichotomized, respectively, into those who stated <4 and

to those who stated ≥4, and used as dependent variable in the regression

analysis.

In the logistic regression model for ADL related to TMD, answers concerning

symptom frequency, intensity, and duration, and age and education were

used as independent variables, first, factor by factor, and then, all factors

that showed a statistically significant relationship to the dependent variable

in the univariate analysis were added into the model in a forward likelihood

ratio analysis. In the logistic regression model for ADL related to headaches

and neck and shoulder pain the same procedure was applied.


24

Before the analysis, the independent variables were recoded as follows: The

frequency of symptoms was recoded as: 0 = No, never/No, not at present; 1

= Once or twice a month at most; and 2 = Once a week to daily. The duration

of each symptom was recoded as 0 = Never had symptoms, 1= <1 year, and 2

= ≥1 year. The intensity of each symptom was recoded as 0 (= 0 on NRS), 1

(= 1–4 on NRS) and 2 (≥5 on NRS). Education was dichotomized into those

who had studied nine years at most and those with longer education (senior

high school or university). Comparison between age groups for presence of

different symptoms in the jawface, head, and neckshoulder region was

done with a chi-square test. Ages were grouped in 10-year clusters (21–30,

31–40, 41–50, 51–60, and 61–70) for descriptive reasons.

Thematic interviews (Paper IV)

Data collection

The selected informants were phoned and an agreement on time and place

for the interview was decided. The women could choose to have the interview

at one of the public dental clinics after working hours or if they preferred, the

interview could be conducted at their home. All women gave their informed

consent and were assured anonymity and confidentiality. I conducted all the

interviews, using a thematic interview guide covering life history, the Sami

heritage, and health and illness experiences and beliefs. The guide was pre-

tested in pilot interviews before the study began. The interviews were tape-

recorded and took 4575 minutes. The interviews were fully transcribed

verbatim and then cross-checked with the tapes for accuracy. The text files

were transferred to a database, Open-Code (ver. 3.3), a computerized tool to

sort and classify the data.

Data analysis

The analysis was based on grounded theory. The first step in the analysis

process is to go through the text, line by line or sentence by sentence, and

write down codes, which are characteristics, and capture what is going on in

the data. The codes are initially close to the text and may be actual words

that the informants use. The next step is to decide which codes are

important, then cluster them together and transform them into categories

with different levels of abstraction. The categories derived must be relevant

and meaningful and describe the phenomenon under study. A category can

be described as a concept with which to organize reality. The codes and

categories are constantly compared with data collected earlier, so that

commonalities and variations can be determined. The data collection ends

when the findings are saturated, that is, the categories are solid and


25

recognizable in all interviews. A major component in GT is the discovery of a

core category. The core category is a pattern of behavior that is relevant for

the study participants and related to the categories identified. The first

coding procedure was performed manually and separately by me and my two

supervisors, going through the texts and annotating the transcripts with

codes and tentative categories in. Numerous meetings followed, involving

comparisons of codes and evolving categories, putting new questions to data,

and formulating a core category and theoretical outlines. Discussions

continued until consensus on the categorizations was reached.


26

Table 4. Example of the process of analysis: quotations, codes, subcategories, and categories

leading to the core category

Quotation

Codes

Sub -categories

Categories

Core Category

I was chewing a caramel and then

something happened here on the left

side, like it jumped out. I don’t know

what happened. And then it swelled up

and that's what I’ve had ever since

then. I think it began with this injury

with the caramel… that there was an

uneven stress and that it affects the

entire body.

Chewing

Something

happened

Don’t know what

Ever since

Impairment

Strain

Musculoskeletal

Problems

Biting

behavior

Inflicted

injury

Bodily strain

Triggers

Grin(d)

and bear

it

No, when I get stressed I bite. I bite

and become so focused on what I’m

doing so that I’m not aware of what

is happening around me. I’m

extremely focused on getting done

whatever is lying around waiting for

me. I bite down and become quiet,

until, until I have finished

doing most of the job.

Stress

Bite together

Focused

Awareness

Active

Bite together

Stress

Bite together

Strain

He [the dentist] examined every which

way. He turned and twisted and

checked everything and he didn’t find

anything wrong. He couldn’t figure

what I had. He was downright rude, I

think.

Examined from all

angles

Nothing wrong

Unfriendly

Blame on me

Ignorance

Mutual

mistrust

Distrust

Sure there are days when you don’t

feel so great, and then I usually think

that it’s just my imagination and then

you get a second wind. In some way

I’ve accepted that you aren’t always at

your best.

Bad days

Not feeling fit

It’s imagination

Come through

Accepted

Not always on top

Visions of

health

Acceptance

Reconciliation

RESULTS

27

Results

Study population

In total, 82% of the women identified themselves as Sami. Six percent stated that they were not quite sure of their affiliation to the Sami population. The majority (63%) of the latter group reported that their uncertainty was because they were not active in reindeer herding or did not speak the Sami language, but their basic family background was nevertheless Sami. Seven percent were married to a Sami. The remaining 30% gave no comments or commented that the question was irrelevant.

Twelve percent of the women did not consider themselves as Sami. The majority of these (53%) stated that their roots were Sami but that they were not living as a Sami or were not viewed as a Sami among other Samis or authorities. Twelve percent of these women were married to a Sami, 24% stated that they were not Sami, but most of them were reindeer owners, and 10% made no comments.

In the total study population of Sami women, 12% reported they were working actively with reindeer herding, and 63% were working outside their homes, twelve percent were retired or had a disability pension, ten percent were studying, and eight percent were unemployed.

The majority of the Sami women (86%) reported that their general state of health was good, whereas 13% reported that their health was not so good, and one percent that it was bad. Almost one of four reported that they had a disease that was under medical care, and 29% had medicine prescribed by physicians on a regular basis.

Symptoms indicative of TMD

The prevalence of ongoing symptoms indicative of TMD varied between 8%

and 32%, depending on the criteria used to determine frequency and

intensity. The prevalence of ongoing symptoms indicative of TMD was 32%,

of which approximately half (17%) were symptoms reported at a frequency of

at least once a week; this was reduced by half again (8%) when only those

were included who also stated that their symptoms intensity level was at 5 or

more on the NRS. When the criterion of impact on daily life, registering

more than one on the NRS was added in, the prevalence was further reduced

to 6% (Figure 3).

RESULTS

28

Figure 3. Percentage distribution of symptoms indicative of temporomandibular disorders, among 487 Sami women, according to the anamnestic dysfunction index (Ai). White bars denote no symptoms (Ai 0); grey bars denote presence of mild symptoms (Ai I,) and black bars denote severe symptoms (Ai II) at different frequency and intensity levels. Symptoms’ intensity as well as their interference with activities of daily living (ADL) was stated on the numerical rating scale (NRS).

Tiredness in the jaws and TMJ sounds were the most commonly reported symptoms indicative of TMD, each being reported by approximately 20% of the women. Pain in the jawface region was reported by 7%. The mean stated intensity of ongoing TMD symptoms on the NRS varied between 3.3 (SD 2.8) and 4.7 (SD 3.1). The lowest mean intensity was stated for TMJ sounds and the highest for TMJ locking. The majority (7496%) reported that their symptoms had been present for more than one year.

The most common frequently occurring symptom indicative of TMD was TMJ sounds (12%). Pain in the jawface region, once a week or more often was reported by 3%. The lowest mean intensity was stated for TMJ sounds (3.9, SD 3.1) and the highest for pain in the jaws (5.8, SD 2.5). The majority

(6798%) reported that their frequent symptoms had been present for more than one year. The highest prevalence of frequent (≥ once a week), longstanding (≥ 1 year) and intense symptoms (≥ 5 on the NRS) indicative of TMD was found for TMJ sounds (5%) and tiredness in the jaws (3%).

The prevalence of frequent symptoms indicative of TMD was significantly

higher among younger than among older women. The odds ratio of reporting frequent symptoms of TMD in the 2130 as compared to the 61- 70-year-old age group was 5.8. The prevalence of frequent, longstanding, and intense symptoms of TMD showed a gradually declining trend with age, but the difference between age groups was not statistically significant (Figure 4).

RESULTS

29

Headaches and neckshoulder pain

More than half of the Sami women reported headaches (61%) and NSP

(56%). When only frequently occurring symptoms were considered, the

prevalence of headaches was reduced to 19%, and of NSP to 30%. Eleven

percent reported frequent and intense headaches, and 21% frequent and

intense NSP. The mean stated intensity level was 6 for both frequent

headaches and frequent NSP. More than 80% reported that these symptoms

had been present for more than one year. The prevalence of longstanding,

intense headaches was significantly higher in the younger age groups than

among the older. The prevalence of frequent headaches showed a gradually

significantly declining trend with age. The pattern of frequent NSP showed a

gradual increase up to the age of 60, but the difference in relation to age

groups was significant only for longstanding, intense neck pain (Figure 4).

Figure 4. Percentage distribution of frequent (once a week or more often) and grievous symptoms of TMD, headache, and NSP, respectively, in five age groups of women in a Sami

population (2130 yr, n = 82; 3140 yr, n = 116; 4150 yr, n = 117; 5160 yr, n = 105; 61 70 yr, n = 67). Grievous denotes that symptoms occurred at least once a week, with a reported severity level of 5 or more on an 11-point numerical rating scale (NRS) and were of at least one-year’s duration.

Disability related to symptoms indicative of TMD

Of those 142 women with ongoing symptoms indicative of TMD and stating a

related impairment of their ADL on an NRS, 57% reported that the

symptoms affected their ADL to some degree and 19% stated a value of 5 or

higher on the NRS. When calculated based on the total sample of Sami

women, 6% thus reported a substantial effect on their ADL from symptoms

indicative of TMD. A total of 8% (n=39) reported longstanding, frequent,

RESULTS

30

intense symptoms indicative of TMD and of these, 77% (n=30) stated that

their symptoms interfered with daily life. All women who reported frequent

jaw pain stated their ADL was negatively affected. The majority of those who

reported no negative interference at all were those with frequent

longstanding TMJ sounds.

In the multivariate analysis including all independent variables that were

statistically significant for an effect on ADL related to TMD in univariate

analyses, low education level, reported intensity level of impaired jaw

opening, reported intensity level of neck pain, and duration of jaw pain

remained in the model as factors significantly related to the women’s

reported effect on ADL related to symptoms indicative of TMD (Figure 5).

Disability related to headaches and neckshoulder pain

Almost half of the study population reported that headaches (47%) or NSP

(48%) to some degree disturbed their daily activities. The interference was

scored 5 or higher among 23% for both headaches and NSP. Twenty-one

percent reported longstanding, frequent and intense pain in the neck and/or

shoulder region, and 97% of these women stated that the pain had a negative

impact on their ADL. Eleven percent reported longstanding, frequent, and

intense headaches, and all of these stated that their headaches negatively

affected daily life.

In the multivariate forward logistic regression model the stated intensity

level of headaches and frequency of tiredness in the jaws remained as factors

significantly related to the women’s statements of the effect of headaches on

ADL.

In the multivariate forward logistic regression model stated intensity level of

pain in the shoulders, stated intensity level of tiredness in the jaws, and

stated intensity level of neck pain were factors that significantly related to

the women’s statement of the effect of NSP on ADL (Figure 5).

RESULTS

31

Figure 5. The black pies show the percentage of those who reported that their symptoms to some degree disturbed their daily life activities. The bars show, respectively, the percentage distribution of the degree of interference with daily life stated on the NRS in relation to the symptoms. Black bars indicate cases and white bars indicate controls used as dependent variables in the regression analysis. Odds ratio (OR) and 95% confidence interval (CI) presented for the significant factors that remained explanatory in multiple logistic regression analysis.

Co-morbidities

A reported impaired general state of health was significantly related to

ongoing TMD symptoms (OR 2.1, 95% CI 1.23.5), ongoing frequent TMD

symptoms (OR 2.7, 95% CI 1.54.8), and longstanding, frequent, and intense

symptoms indicative of TMD (OR 2.8, 95% CI 1.36.0). Statistically significant associations between frequent symptoms indicative of TMD and frequent headaches, between frequent symptoms indicative of

RESULTS

32

TMD and frequent neckshoulder pain, and between frequent headaches and frequent neckshoulder pain were found. These associations were similar when the criteria of longstanding and intense were added. Approximately 50 % of those with frequent and more intense symptoms indicative of TMD as well as of those with frequent and more intense headaches also had frequent symptoms in the neck-shoulder region (Figure 6).

Figure 6: Relationship between women who reported longstanding, frequent symptoms

indicative of TMD, headaches and neckshoulder pain (NSP) with an intensity level of 5 to 10 on an 11-point numerical rating scale (NRS). Odds ratio (OR) and 95% confidence interval of the relationship between cases with the symptoms.

Case–control study

The mean age of the clinically examined study population was 48.7 years (SD

13.1). The positive predictive value of having signs and frequent symptoms

indicative of TMD was 0.82; the negative predictive value was 0.87 at the

two-year follow-up. An annual incidence rate of TMD was 6.5% among

controls. Cases had significantly higher odds ratios of reporting impaired

general health, taking prescribed medication, and being aware of tooth

clenching and tongue pressing than the controls. A diagnosis in accordance

with the RDC/TMD classification system was established in 59% of cases.

Symptomatic TMJ disc displacement was diagnosed in 46% of cases

compared to diagnosis in 7% of the controls (P < 0.001). Myofascial pain was

diagnosed in 40% of cases as compared to 2% of controls (P < 0.001).

Diagnoses of TMJ arthralgia and TMJ arthrosis were established in 5% and

9%, respectively, of cases, but in none of the controls; the difference between

cases and controls was not statistically significant. The distribution of

symptoms (Ai) and clinical signs (Di) of dysfunction is presented in Figure 7.

In total, 91% of cases had signs of dysfunction compared to 37% of controls.

RESULTS

33

Figure 7. Percentage distribution of frequent (≥ once a week) symptoms (A) and signs of TMD (B) among controls (white bars) and TMD cases (black bars) in Sami women. A. Ai 0 denotes no symptoms, Ai I denotes mild symptoms, and Ai II denotes severe symptoms of dysfunction. B. Di 0 denotes no signs, Di I denotes mild signs, Di II denotes moderate signs, and Di III denotes severe signs of dysfunction.

The following clinical observations were made among cases and controls:

Dental occlusion

Two subjects, one in each group, were edentulous. The mean number of teeth was 25.2 (SD 7.2) with no statistically

significant difference between cases and controls. No statistically significant difference was found between cases and

controls in classifications of morphologic occlusion (neutrocclusion 72%, distocclusion 27%, mesiocclusion 1.5%, deep bite 16%, open bite 3%, edge-to-edge bite 8%, cross bite 8%, and scissors bite 3%).

No statistically significant difference was found between cases and controls for contact patterns in centric relation (unilateral contact in 57%), or slide in centric or contact patterns in eccentric positions.

Cases had fewer contacting pair of teeth in centric occlusion (mean 8.2, SD 2.9) than controls (mean 9.8, SD 2.8) (P =0.034).

There was no significant difference between cases and controls in the distribution of supporting occlusal zones according to the Eichner index.

RESULTS

34

Degree of tooth wear Forty-three percent of the cases were registered with considerable

tooth wear and with obvious change of anatomical tooth form (Mike or Tango) compared to 36% of controls. No significant differences were found between cases and controls.

Mandibular mobility No statistically significant difference was found between cases and

controls for mandibular mobility. The mean maximal jaw opening capacity was 48.4 mm (SD 6.5), the mean laterotrusion to the right side was 9.1 mm (SD 2.5), the mean laterotrusion to the left side was 9.0 mm (SD 2.7), and the mean maximal protrusion was 8.7 mm (SD 2.2).

TMJ signs Temporomandibular joint sounds were registered in 50% of cases

and 9% of controls (P <0.001).

Tenderness to palpation over the TMJ (lateral and/or posterior) was registered in 4.5% of cases and 2.2% of controls, with no statistically significant difference between the two groups.

Pain was elicited from the TMJ region in 26% of the cases and in none of the controls (P =0.002).

Muscle signs Tenderness to palpation over jaw muscle sites was registered in

68% of cases and 20% of controls (P <0.001).

Forty-five percent of cases developed symptoms during a 30- second clenching task compared to 15% of controls (P =0.007).

Perception thresholds All those included in the study population had similar tactile

perception thresholds at all tested regions of the face, as determined with von Frey filaments.

BMI The cases had a statistically significantly (P =0.027) higher body

mass index (28.2) than did the controls (25.4).

RESULTS

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Thematic interviews

The core category derived from the categories was “Grin(d) and bear it.” It

summarizes the informants’ various ways and stages of processing and

handling the interacting categories that emerged in the analysis: (1) triggers,

(2) strains, (3) distrust, and (4) reconciliation with pain and/or difficulties in

life (Figure 8).

Figure 8: Grounded theory model. The figure illustrates the interaction between triggering factors, perpetuating factors such as different stress and strain life situations, and curative circumstances. Distrust can be directed towards the caregiver; it can also mean a feeling of being mistrusted.

For women with TMD the core category described their awareness of regular

tooth-clenching behavior whenever they were in pain or stressed. Informants

without TMD used the same expression, but more as a metaphor for a

strategy for handling difficulties in life.

Women with TMD expressed both similar and divergent understandings and

experiences of related impairments. The women without TMD contributed

foremost with their thoughts regarding factors that helped them to handle

strains, reconcile, and stay healthy. Women with and without TMD seemed

to cope differently with life situations. The healthy women handled

difficulties in life by leaving bad experiences behind; they were looking

forward and striving to get on with life, despite any difficulties. To succeed in

this strategy, they relied heavily on support from family and friends. The

women with persistent symptoms of TMD described a life situation

characterized by a limited social network, loneliness, and a feeling of being

an outsider, off the labor market and also outside the health care service.

They did not know where to find help for their symptoms. They also

expressed feeling unsafe and uneasy. All informants expressed both negative

and positive experiences of the Sami heritage.

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The following section presents the four categories that emerged from the

analysis.

Triggers

This category involves reflections and possible etiological explanations of

why and how pain symptoms in the jaws might evolve. These explanations

were varying; the onset was sometimes related to a sudden local injury, in

the orofacial area, in the neck, or elsewhere. Mostly, however, the jaw

dysfunction had evolved insidiously.

Co-morbidities were described between TMD symptoms and symptoms from

the neck and shoulder region. Diseases, such as sinusitis, muscle diseases,

rheumatic diseases, asthma, glaucoma, and hypertension were also reported.

“Well, I think that’s because of my muscular disease. Oh yes, there’s a

connection, all right. And that I tense up when get stressed, and then

my jaw gets tight.”

One woman related her jaw problem to an ankle fracture a long time ago,

which she believed had changed her body posture and thereby caused TMD.

“It has developed very gradually, but I believe a lot of the damage

happened that time in ´87 when I hurt myself—that I put on weight

and got this postural imbalance. I don’t know if that’s a part of it. That

my body has gone crooked.”

One woman related her problems to a virus infection in the 8th cranial

nerve. Another woman thought heredity might be a cause, as her mother had

arthritis and her father had rheumatic disease.

“So you wonder, is it something hereditary is it something in our genes

that caused it, or just what is it? Because the fact is that of the five of us

siblings, none of us is really healthy. Everyone has pain in some joint

or muscle.”

Some women with TMD linked their pain to dental treatments, such as a

tooth extraction or a dental prosthesis. One woman had to clench the jaws

together to keep her dentures in place. Bruxism, such as, tooth clenching and

tooth grinding, were common explanations suggested by the women with

TMD.

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The women without TMD offered possible reasons for why they had

managed to avoid having TMD; for example they had few medical problems,

and no muscle tenderness or hereditary muscle problems. The impact of

financial or other personal problems on health was also mentioned:

“Maybe it’s because I'm not stressed. I don’t lie around, gnashing my

teeth.... I think you develop pain if you have this kind of stress, money

worries and one thing after the other. In the end it just gets to be too

much. I don’t have anything like that.”

They also more often described awareness of ergonomic relationships to

musculoskeletal disorders.

...and at work I think about lifting properly, so then it doesn’t happen,

either.

Physical activities during childhood, protecting them from pain and

dysfunction disorders were also considered.

“And it may also be because when we were little, we also had to work a

lot. Carry in wood and carry water and work hard outdoors…. That

you’ve really built up your muscles. That could be it. And we were

outdoors a lot and went skiing and sledding. We were active. Really

active. We were rarely indoors. I don’t know if it has to do with that.”

Strains

This category involves behaviors of biting/clenching/holding teeth together,

mental strain, bodily strain, and stress. A relationship between stressful

situations and tensions or pain in the body, foremost from the jaw-face,

head, and neck region, but also in other locations was described. The women

mentioned awareness of biting, clenching, or holding their teeth together in

specific life situations. Some reported these activities as a part of their

normal everyday behavior, a momentary event; others, as an ongoing habit:

“Yes, I’m always sitting around with my teeth clenched. You see, I

grind my teeth a lot, you know. I feel like I wake up with it. I can wake

up with the worst headache in the world, and my jaw is stiff. And it’s

because I’ve clenched my teeth, quite simply.”

“When I’m lying down reading, I lie there and clench my teeth. I sometimes notice then that my muscles are getting tired.”

RESULTS

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Some women had common experiences of difficulties in early life and

recalled various stressful situations, for example early separations from their

parents, as they were sent to nomadic schools—special schools for Sami

children from the age of seven, and other traumatic events such as teasing

and harassment by other school children.

“When you got to school, you didn’t know anyone. There was one

person who became my guardian angel. When she graduated, you

could say that all hell broke loose. I was bullied then, and it wasn’t

much fun.”

Feelings of having been treated as outsiders by the majority group, and

experiences of marginalization of the Sami society under Swedish laws were

also expressed. Many had been forbidden to speak their mother tongue and

had therefore lost their Sami language, one important marker of ethnic

affiliation. Situations where they had to defend the Sami people and culture,

and sometimes had chosen to hide their Sami origin, were also described.

Distrust

This category involves feelings of mistrust and distrust regarding the

women’s contacts with medical and/or dental health services. They

expressed a belief that physicians and dentists suspected that their main

objective was to be on sick leave or to have other secondary gains. They

shared negative experiences of the general health services, and also

mentioned inaccessibility.

“And he asked if I wanted to go on sick leave. I got angry at him. I said

that I don’t run here because I want to go on sick leave; I come because

I want to get help. And, yes, we discussed it—in the end I felt that he

did not believe anything I said, so I walked away. I said that I have no

reason to be here if you don’t believe me, and so I left. Yeah, he was

really stupid, in my opinion.”

Some women expressed mistrust of the care providers’ competence and

ability to manage their problems:

“What kind of a doctor could there be who would understand this? I’ve

looked high and low.”

Mistrust towards treatment received was also described. Many reported that

they had tried oral splints or adjustments of the occlusion. Their common

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experiences of these treatments were that they had no major effect on

symptoms.

“I've had oral splints. I've tried several of them, but I don’t know that

I’ve gotten any better.

A few women expressed passiveness regarding things they needed to manage, for example, physical activities, work ability, and household work. They seemed to be stuck within the pain condition, which was keeping them back from enacting changes in their lives.”

“I wish it would just disappear. That I could move my body more without feeling absolutely numb with pain. Do something at home without feeling sudden pain, like, “Oops, can’t do that now” … Yeah… If only I’d been spared that part, I could have gotten through anything.”

Reconciliation

This category describes the Sami women’s wish, intention, and strength to

“bear it” and move on with life, despite difficulties.

The women related to their Sami heritage with pride and appreciation for the

possibility of gaining health: a free, unrestricted, and sound life “up in the

mountains.” To be included and accepted in the Sami group was also of great

importance.

“Then I’ve like, I’ve like felt that when I’ve been having a really rough time, I’ve gone out into nature. Gotten connected—so I’ve meditated a great deal, gone to yoga class and stuff like that. And it’s a way for me to feel I can, you know, keep on going with this. That I need to get out into the wilderness, so my kids can say, “Mom, here’s a place where you can meditate.”

The women described different physical activities undertaken to improve

their well-being. The majority also utilized care from different professions,

such as physicians, physiotherapists, and dental surgeons, and also from

alternative medicine therapists, in their search for alleviation.

Self-treatments were a part of the women’s strategy to find their own way to

manage daily life. Over-the-counter medicine, stretching, and massage were

common examples mentioned.

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“Yes, I often have a headache and feel stiff in the jaw. I try to sit down somewhere then and massage myself. And then I feel after a while it goes away and my muscles relax—and they’re always tense.”

“I try now—I take an analgesic and try to massage the back of my head a little. It usually helps. If my head and my jaw are really hurting I’ll take a warm shower, and that makes me feel better.”

Some women had reached a point of acceptance and tried to make the best of

their situation:

“In some way I’ve accepted that you aren’t always at your best. You

can’t always feel so great. It’s just sometimes like this.”

Social networks with others in the same situation were important for

managing their longstanding TMD problems.

“Then I meet up with my fibromyalgia buddies, and that’s so nice. Because we understand each other. They’re not any healthier than I am—some of them are actually worse off some days—and we cheer each other up and encourage each other.”

The healthy women seemed to handle difficulties in life by leaving bad

experiences behind, looking forward, and striving to get on with their lives,

despite difficulties. To succeed in this strategy they relied heavily on support

from family and friends. They tended to have a more conciliatory approach

to solving problems and handling shortcomings:

“I try to manage to get the (important) things done that I have to do.

In other words, I know that maybe I planned so I would have time to

do more, but then I don’t. It really doesn’t matter. If you don’t have

time, you don’t have time.”

Good health was mainly described and perceived by the women in terms of

ability to work and having energy left for leisure time.

“If you don’t have the strength for physical activities, you don’t have

good health and quality of life.”

Other important factors related to good health were feelings of safety,

freedom, good mental health, stable finances, and a healthy family.

DISCUSSION

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Discussion

Main findings

Signs and symptoms indicative of temporomandibular disorders, headaches and neckshoulder pain, were common conditions in Sami women living in the Arctic region of Sweden. The prevalence of these conditions was essentially similar to those reported in other population studies on women. It should be emphasized that any reported prevalence of TMD symptoms strongly depends on the criteria used for frequency and intensity. There was a tendency of higher prevalence of headaches and TMD in the younger compared to the older Sami women. This finding is in line with studies on the general population in Västerbotten, Sweden (Yekkalam and Wänman 2014a), and in Jönköping, Sweden (Anastassaki and Magnusson 2004). The study also indicates that for quite a large part of the Sami women, the activities of daily living were negatively influenced by the frequency, intensity, and duration of pain in the jawface region together with impaired jaw opening and co-morbid symptoms of pain in the neck. The results are in agreement with those from a systematic review that demonstrated that OHRQoL of life was negatively affected among TMD patients (Dahlström and Carlsson 2010). Epidemiological studies have seldom found that variations in the dental occlusion have had a major impact on prevalence of TMD (Carlsson 2010, Türp and Schindler 2012). This study was no exception, since occlusion did not clearly distinguish whether a Sami woman was a TMD case or not, in the cross-sectional analysis. TMD cases reported impaired general state of health and awareness of parafunctions more frequently than controls.

In the qualitative part of the study the narratives from Sami women with more severe and longstanding symptoms of TMD relayed that they perceived that the jaw often felt strained. Although the informants (TMD cases) were strategically selected based on their TMD signs and symptoms all of these also had other symptoms such as headaches, NSP and tinnitus. The Sami women shared common thoughts and experiences about factors that might trigger and perpetuate TMD symptoms, headaches, and NSP. In the narratives they expressed distrust, one on hand, in the capabilities of the health care providers to handle symptoms of pain and dysfunction, but also reconciliation experiences, on the other, indicating that these women’s needs had not been met by the dental and health care system.

Study population

Epidemiology as a scientific method focuses on the incidence, prevalence and determinants of disease in human populations. Patterns of illness in the population are examined to try to gain knowledge about why certain

DISCUSSION

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individuals develop a specific disease, whereas others do not (Greenberg et al. 2001).

The Sami population may from certain perspectives be viewed as a fairly homogenous group, with regard to ethnicity, culture, traditions, resources, language, geographic living area, and to some extent, also genetics. As such, they may help to add knowledge about development and determinants of specific diseases. The Sami society of today can be regarded as integrated into the Swedish society. According to the thesis by Andrea Amft from 2004, marriage within the Sami society is not longer a necessity. She also reported that Sami women traditionally take more responsibility than men for care of children and household chores, as in most other cultures. Responsibility for the products of the reindeer herding enterprise, such as food and materials for sewing clothes, has traditionally also been among the Sami women’s duties (Amft 2000). Only the oldest women in this population had experience of a more traditional, nomadic way of living.

The feeling of considering themselves included in the Sami society was addressed in one question. Despite the study population having been defined according to the Sami Parliament’s criteria, almost one out of five expressed doubts of being regarded as a Sami. This result may reflect that having heredity in the Sami culture is not enough, if they are not viewed as a Sami by other Samis or authorities. Identity is created through discourse, and not automatically transferred. Although a person is born Sami, but it is the person’s upbringing that determinates whether the person becomes a Sami. Sami women have to subordinate themselves to be a “genuine” Sami, and if a woman were to take a political stand as both a Sami and a woman, she might risk being defined as an outsider in relation to the ethnic group (Amft 2000). Some women in this study had difficulties in identifying themselves as Sami since their membership in the electoral register was related to matrimony. They were nevertheless a part of the Sami society and culture. Three percent of the women had a reindeer mark, were registered in the Swedish Board of Agriculture, and stated that they were not Sami. In our analyses, we did not find that there were any significant differences in the distribution of answers between those who were active in reindeer herding and not, and between those who stated that they were Sami and the rest of the sample. The study population included in this thesis may be considered as a fairly homogeneous sample in the sense that they are all women who share the Sami heritage and are living in the Swedish Arctic region.

The strategic choice to exclusively study women was based on the indications

that TMD symptoms, headaches, and neckshoulder pain are more common in women (Bovim et al. 1994, LeResche 1997a, Jensen 1999,), and that longstanding TMD pain and dysfunction are more commonly observed in women than in men (Wänman 1996, Kuttila et al. 1998, Rantala et al. 2003, Goncalves et al. 2010). Longitudinal studies of TMD have shown a fairly

DISCUSSION

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consistent pattern of predominantly transient symptoms of pain and dysfunction with time (Könönen and Nyström 1993, Kitai et al. 1997, Magnusson et al. 2000, Nilsson et al. 2007). However, in a 10-year prospective study, women were at higher risk of reporting longstanding symptoms, even though significant fluctuations in TMD symptoms occurred over the period (Wänman 1996). There may be unknown factors involved in the maintenance of symptoms that relate to the female gender. Several hypotheses regarding this issue have been proposed, including psychosocial factors (LeResche 1997a, Dao and LeResche 2000, Rantala et al. 2003) and sex hormones (LeResche 1997b, Warren and Fried 2001, Cairns and Gazerani 2009, Cairns 2010). The role of genetic variation in relation to development of TMD is currently addressed in a large prospective research project-OPPERA (Smith et al. 2013). Several factors may thus be related to TMD pain, but no conclusive knowledge has yet been reached. These findings were also reasons for studying a fairly well-defined sample of Sami women from different perspectives. Since symptoms indicative of TMD, headaches, and NSP have fairly high prevalence, the size of the study population was considered acceptable. Dropouts complicate the assumptions and may jeopardize the study results. In the questionnaire study the dropout rate was approximately one out of three. Since the dropout analysis did not indicate any systematic errors related to presence of the symptoms in focus, the study results could be considered reliable. The risk of sampling error was small since all available individuals from the Sami register were included. The register on the other hand represents a clearly biased group in relation to the total Swedish population. The most common reason given for declining to participate was “on principle.” Discrimination was also mentioned as a reason. Stigmatization can occur among Indigenous Peoples, and discrimination of Samis is an ongoing debate (DO2008:1, DO2008:2, Ledman 2012a, Omma 2013).

Methodological considerations

Questionnaire

The balance between the number of questions included in a questionnaire and the expected number of participants willing to take the time to answers all the questions in population-based studies influenced the design of the questionnaire. It was structured around defined symptoms and their occurrence, intensity and duration. A question may address a condition’s occurrence on a lifetime, yearly, monthly, weekly, or daily basis. It is obvious that the outcome will be influenced by the wordings used. It has previously been reported that the reliability of answers to questions regarding symptoms of TMD increases when a frequency of once a week or more often is used as the time frame and probably also the “clinical relevance” increase when this time frame is used as an inclusion criterion (Nydell et al. 1994, Wahlund et al. 1998, List et al. 1999). In this study the questions were

DISCUSSION

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constructed so the prevalence could be calculated for different time frames in order to compare the results with previous studies and to identify women with more frequent, intense, longstanding, and disabling symptoms for the subsequent thematic interviews.

To assess the intensity of symptoms as well as the impairment related to TMD symptoms, headaches, and neck-shoulder pain the NRS was used. Rating scales are commonly used to capture pain intensity and shown to have an acceptable reliability (List and Helkimo 1995, Conti et al. 2001, , Williamson and Hoggart 2005), as well as having the advantage of also being easy for participants to understand (Williams et al. 2000). Disadvantages of a rating scale are that the individual’s interpretation of the scale may differ, and thus, inter-individual comparisons are scarce. The scales can also be criticized for being one-dimensional. The validity of the NRS for capturing the severity of impact on daily life is not known. In the analysis of TMD the scale was dichotomized into those who stated no interference at all and the remaining women which we considered reasonable in relation to the analysis. The dependent variable was thus composed of an approximately equal number of those with and without impairment related to TMD symptoms. In the corresponding analyses of impairment related to headaches and NSP, the dichotomizing split was based on the distribution of the response, also creating an approximately equal numerical size in both groups. In the graded chronic pain scale (Von Korff et al. 1992) the pain score is dichotomized into the lower (<5) and higher (≥5) levels. The split in this sample may thus be interpreted as between those with a lower and a higher impairment related to headaches and neck‒shoulder pain,

respectively.

Different classification systems were used to cluster the women’s TMD‒related symptoms, using the RDC/TMD criteria to establish a

diagnosis (Dworkin and LeResche 1992), and the Ai and Di for severity of dysfunction. Both systems are well-established and internationally used classification systems. The Helkimo indices have been criticized (van der Weele and Dibbets 1987) and the RDC/TMD recently adjusted (Schiffman et al. 2014). The Ai captures presence of symptoms indicative of TMD. Based on the results from the present study, the index division in severity may be questioned. The severity of a condition is a subjective experience, and the subjects’ reports of symptoms’ intensity levels and their affect on daily life expressed on the NRS were similar for Ai 1 (mild symptoms) and Ai 2 (severe symptoms), as shown in figure 3. In support of the division used was the observation that most of those who reported no affect on daily life were those with TMJ sounds. The RDC/TMD diagnostic system may also be criticized, since it has its main focus on pain conditions, which is too limitative for the disorder. In this study population TMD pain had certainly affected the women’s ADL, but so had symptoms of dysfunction.

DISCUSSION

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Case‒control study

The design of the case–control study was to compare individuals with symptoms indicative of TMD and those without symptoms, as identified by the questionnaire. The study has several strengths: cases and controls were selected from the same population, and thus had the same sex, ethnicity, and culture. Cases were identified based on severity of their symptoms and not on their status as consulting patients or as referrals. Twice as many controls as cases were included, and they were age-matched. The selection also focused on the extremes at each end of a normal distribution, with regard to severity of symptoms in the jaw–face region. The examiner (AW) was an experienced TMD specialist, and throughout the study was kept blinded to the women’s affiliation. Since two years passed between the first and second examinations, the identified cases really could be defined as severe cases with persistent TMD symptoms. Only those who subjectively considered themselves as Sami were included, because one of the themes of the subsequent, planned, thematic interview study was the life experience of being a Sami woman.

Because of relatively few cases twice as many controls were selected. Nothing, however, indicates that dropout was related to changes in TMD symptoms. The main reason for dropping out was that they could not be reached because they had moved away from the included municipalities. There were no statistically significant differences in answers to the first questionnaire between the participating women and those who were not accessible. Having a small number of participants increases the risk of making a type-2 error in data interpretation and accepting a null hypothesis, even though it is false. The distributions of most clinical variables examined in the cases and controls were, however, quite similar, so even a significant increase in the number of cases and controls would hardly have changed the interpretation of the results.

Interview study

The qualitative research approach was used to get insights into the women’s experiences and beliefs and to generate hypotheses of factors that might influence the development of longstanding TMD. The informants were strategically selected from the epidemiological sample, which may increase transferability. The selection of informants was based on their experience of having longstanding, severe TMD symptoms, or having no experience of TMD, and being approximately the same ages. The women who were included had consequently varying experiences relating to education level, family status, and working conditions, as a reflection of their different social living conditions. No Sami woman in the older ages was included, since there was no one available with severe symptoms. This finding is interesting by

DISCUSSION

46

itself and may warrant further qualitative studies addressing specifically women after retirement.

Grounded theory was chosen, as it is an established method used to explore complex phenomena and patient experiences in the health sector. The data collection ended when the categories were considered solid and recognizable in the interviews. To enhance credibility, triangulation, peer debriefing, and negative case analysis (Dahlgren et al. 2004) were used. The three of us researchers, separately performed the coding procedure, and meetings and discussions ensued until consensus had been reached. We all had different backgrounds, pre-understandings, experiences, and perspectives, which were considered an advantage, as it contributed to triangulation in the analysis procedure. I have, as a native Sami woman myself, an “insider perspective,” used as knowledge. The other two investigators provided the perspectives of a male dentist specialized in TMD (AW) and a female general practitioner (EEJ) with specific interest in chronic pain conditions. Preliminary findings were discussed with colleagues outside the process for inputs and comments, assigned to peer debriefing. Negative cases were included as references, not for direct comparisons, but to distinguish general life experiences among Sami women and those more specific to TMD cases.

Ethical considerations

The study was approved by the Regional Ethical Review Board at Umeå University, Sweden. As the ethical review in Sweden does not specifically consider Sami perspectives, I have chosen to relate to ethics more thoroughly than is required by Swedish law (SFS2003:460), as discussed by Ledman (Ledman 2012a). In practice, this implies that the study also has been carried out in contact with the Sami Parliament in Sweden. They approved the use of the electoral register and have also supported the study with grants. The results have been reported to the Sami Parliament for those papers they have supported. The results have also been reported in public, in conferences both within the field and also on a conference with Sami context. The study received attention in Sami media when it started, and my intention is also to report the final results in a more popular form. From these perspectives the research process has been transparent, and the Sami society has been given the opportunity to take part in this process. This approach is in line with what is recommended within international standards for indigenous research (Ledman 2012a, Smith 2012).

In studies of a specific group of people, as in this case, a specific gender and

an ethnic minority, stigmatization is a potential risk, as both the individual

and the group may believe they are being accused. The risk in this case was

considered low. As a native Sami, I might have increased the participants’

confidence. Even as an insider, one may have an outsider perspective (Åhren

2008). It is, however, more likely that the insider brings more familiarity

DISCUSSION

47

with the prevailing norms and values and can use this pre-understanding in

all phases of the research process. An example of being an insider for me was

that during the interviews an informant sometimes did not explain deeply

her experiences, instead commenting, “...but you know how it is‒you are a

Sami woman yourself.”

Epidemiological studies on the Sami population in Sweden were, at the

beginning of the year 2000 when this study was initiated, limited.

Knowledge about the health situation and living conditions has since

increased and is still increasing and required. In other countries with

Indigenous peoples, such as Canada, Australia, United States and New

Zealand, certain ethic guidelines for indigenous research have been

developed. These have been designed according to the Indigenous people’s

own values, standard, and requirements (Ledman 2012a). Such ethical

guidelines are not available in Sweden, but are warranted (Nilsson LM

2012). As the indigenous researcher Linda Tuhiwai Smith wrote in her book,

Decolonizing Methodologies, “research is probably one of the dirtiest words

in the indigenous world’s vocabulary” (Smith 2012). I also experienced some

skepticism, especially when the questionnaires were sent out. Some came

back with comments about the negative feeling of being selected through a

register. They mentioned the dark era in Swedish history with the race

biology studies, on the Sami people, who were considered a lower status race

during that time (Ledman 2012b, Lundmark 2007). The researcher may be

presumed to represent all the research that has conducted on the Sami

people, including research perceived as negative (Ledman 2012a). This is a

further aspect to have in mind when entering into a project with indigenous

themes.

Ethical risk is always to be considered in research of humans. The study was

conducted following the ethical principles for medical research involving

human subjects according to the World Medical Association Declaration of

Helsinki and the basic ethical principles in human research in accordance

with the International guidelines for ethical review of epidemiological

studies. The principle of respect for persons, meaning for their autonomy

and their capacity for self-determination has been relevant throughout the

study. The women decided by themselves to first participate in the

questionnaire. For the follow-up study they once again decided to

participate, and also for the subsequent interview. They were informed

during the follow-up (clinical examination) that they might be invited to an

interview. All of them gave their consent to be contacted by phoned and

asked for their agreement, and they could also choose to decline to

participate at that occasion. It has been my intention to give information as

much as possible about the study aims during the data collection process. I

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believe that it was one of the reasons why all of them whom I met in clinical

settings agreed to be invited for an interview. All the participants were

informed orally and in writing about the aims. They were all assured

confidentiality and the opportunity to withdraw from the study anytime

without having to specify reasons for leaving. This promotes freedom of

choice. The study was thus conducted with respect for the right of informed

consent. A balance between benefit and harm must always be considered in

planning process of the research process. The benefit of this study was

considered at the individual level, that those with longstanding pain

symptoms could have the opportunity to obtain diagnosis, advice and

assistance. On group level possible factors of importance within the group

could be identified and lead to proposals for preventive measures. On

community level, knowledge of factors important for the development of

longstanding TMD is still lacking, and the study may generate increased

knowledge in this area. The principle of beneficence means that the expected

benefits of the research should be larger than the harms (non-maleficence).

In this study, a possible harm could be pain experienced by women during

the clinical examination. On the other hand, those participants also could get

some benefits in the form of advice for pain relief. In epidemiological

studies, particularly in clinical examinations, a sudden unexpected and

undesired diagnosis can be found. In this study, in the field of TMD,

however, no fatal diseases were expected. A benefit can instead be that the

participant was advised to contact her regular dentist or was referred to a

specialist in TMD, providing further assessments. The principle of justice has

been applied when it has been applicable. The women with pain might had

been more vulnerable than the women without pain; all were been treated

equally. Transportations costs were supported, so also those who had a

longer distance to the examination had the same chance to participate

without incurring any costs. There is also a potential risk of the participants

feeling subordinate to the researcher. It is my belief that as a native Sami

woman myself, I reduced that risk.

All data have been treated confidentially. Questionnaires and interviews

were done anonymously and stored, locked up, in a location separate from

the code keys. Even though the population was spread between two different

communities and areas within the communities (for example, Karesuando),

the Sami population have close internal contacts; many are even relatives.

No information regarding geographic area was presented, so it would not be

possible to identify specific individuals from the interviews. All quantitative

data were givens serial numbers, which were kept away from personal

identification data. The analyses were done at group level, and the

participants were remained anonymous throughout the analyses, with the

results being presented only at group levels.

DISCUSSION

49

Qualitative methodology is regarded as less threatening on an individual

level because of the close interactions between the researcher and the

informant. It has also been suggested that the methodology empowers

people through their active participation in the process (Dahlgren et al.

2004). In the qualitative study, the participants were informed that

researchers other than the interviewer were also going to work with the text

files. Confidentiality was assured. Private data such as name and so on were

kept away from the text files and would not be reported. The audio files were

coded and locked away. The key code linking personal identification to a

given code number was stored elsewhere. The ethical risks of being a

participant in an interview study may include the interviewer getting too

close to their life experiences, which may result in stress and fear about the

questions asked. This risk was considered as small, since the women were

informed about the topics in the beginning of the interview and told that

they could choose not to answer the questions if they felt that they did not

want to, without offering any explanations. The participants may also start to

reflect up on well-being and potential stress events, which may lead to

improved self-efficacy. It can be a benefit that someone takes time to listen

to their stories.

Temporomandibular disorders

Prevalence

The prevalence of symptoms indicative of TMD was lower among the Sami women than the prevalence observed in a Sami population examined in the early 1970s. These Skolt and Inari Lapps were at that time more or less uninfluenced by other cultures due to isolation and a high degree of marriage within their society. Their economical standard was low and living conditions simple. They also had a bad dental status but their general health was otherwise good (Helkimo 1974a). The prevalence among the Sami women in this study was close to a median value of symptoms based on several population based studies (Carlsson 1984, Salonen et al. 1990, De Kanter et al. 1993, Rantala et al. 2003,), which, on the other hand, were based on both men and women. In comparison to a survey in Västerbotten in 2002 (Yekkalam and Wänman 2014a) the prevalence of frequent symptoms, as well as the age distribution with higher prevalence in the younger as compared to the older women was similar, except that the peak of prevalence observed in the 50-year-old women in Västerbotten was not obvious in the Sami women. A similar age peak was reported based on a TMD patient sample (Manfredini et al. 2010a). The different prevalence figures related to symptoms indicative of TMD depending on the symptoms reported frequency, stated intensity, and interference with daily living may imply that for most individuals in the general population symptoms of TMD are of low

DISCUSSION

50

or inconsistent frequency, or low and manageable intensity. Most individuals thus seem to cope with these symptoms and do not demand treatment. The 6‒8% who reported more significant symptoms of TMD resembled estimated

treatment needs in the adult population (Agerberg and Carlsson 1975, Locker 1988, Alanen et al. 1997, Kuttila et al. 1998, Carlsson 1999). The results therefore add understanding to why previous fairly high prevalence figures reported in epidemiological studies never have been directly transformed into treatment. The demand for treatment is not based just on the bare presence of signs and symptoms indicative of TMD; the frequency, intensity, duration, and disability has a significant influence also (Macfarlane et al. 2003). These factors may not only increase the reliability but also the clinical relevance in studies of TMD. Prospective studies based on non‒patient samples have shown a fluctuating pattern of TMD symptoms

and that individuals with such mild, and inconsistent symptoms rarely develop more severe TMD (Könönen and Nyström 1993, Carlsson 1999, Magnusson et al. 2000). The most commonly reported symptoms indicative of TMD were feelings of tiredness in the jaws and TMJ sounds, in agreement with many previous studies (Helkimo et al. 1972, Carlsson 1984, Wänman 1987, Salonen et al. 1990, Nydell et al. 1994, Wänman 1996, Magnusson et al. 2000). Notable was that almost twice as many (6.1%) reported frequent, intense, and longstanding dysfunctional symptoms as reported frequent, intense, and longstanding pain (3.8%). Since there seem to have been a gradual shift in the professions’ view on TMD from dysfunction to pain, these opinions may need to be reconsidered.

Impact on daily life

Remarkably small differences in the distribution of the rated intensities between the different symptoms were observed. Feelings of tiredness in the jaws were rated as almost as intense/disturbing as pain in the jaws. The symptom that was given the lowest intensity level was TMJ sounds. Seventeen percent stated that their symptoms indicative of TMD to some degree interfered with activities of daily living of which presence of frequent, intensive jaw pain of long duration had the highest impact, together with impaired jaw opening. The results are in accord with previous studies showing that patients with myofascial pain, arthralgia, or disc displacement without reduction have reported a higher impairment than patients with disc displacement with reduction (John et al. 2007, Reissmann et al. 2007, Rener-Sitar et al. 2008, Barros Vde et al. 2009). The results from the present study also resemble a previously reported, epidemiological study, where 14% of those with facial pain and 48% of those with severe headaches reported that, at times, they were unable to carry on some activities because of the pain (Von Korff et al. 1988). In a review on TMD and its relation to oral health-related quality of life, non-painful conditions had less impact on

OHRQoL than painful conditions (Dahlström and Carlsson 2010). Among Sami women, TMJ sounds also dominated among those who stated no

DISCUSSION

51

disability related to the condition. The results indicate that most individuals, with non-painful joint sounds, adapt to the condition and thus are less disabled than they would be by painful conditions. Patients with myofascial pain more often used splints, consulted more physicians, and received more physiotherapy than patients with joint pathology (Schmitter et al. 2005). Sleep disturbances, impaired mood, and difficulties in chewing are other possible consequences of TMD pain (Murray et al. 1996). Even children with TMD symptoms report impaired quality of life, limited physical activities, and effects on their schoolwork and on activities with friends (Jedel et al. 2007). A higher absence from school and higher consumption of over-the-counter analgesics among adolescents with TMD pain were noted in a Swedish sample (Nilsson et al. 2009), as well as consequences for all aspects of their lives, even when the pain was absent the adolescents were constantly thinking of their pain (Nilsson et al. 2011). The incidence of pain in the jaw, TMJ and temple region seems to coincidence with the early teen-age period (Nilsson et al. 2007). With reference to the negative consequences for the quality of life (Dahlström and Carlsson 2010, John et al. 2007, Anderson et al. 2011) affected individuals should be identified in the dental health care systems as early as possible.

Influence of age

The lowest prevalence of the pain conditions examined was observed in the oldest age group. This is in agreement with previous studies in which older individuals reported TMD symptoms less often than younger ones (Schmidt-Kaunisaho et al. 1994, Österberg et al. 1992). For headaches as well, young and middle-aged groups reported the highest prevalence and thereafter prevalence declined with age (Anastassaki et al. 2012, Radtke and Neuhauser 2009, Yekkalam and Wänman 2014a). Frequent as well as grievous TMD symptoms and headaches declined with age, but not the related disability stated on the NRS. The prevalence pattern of these symptoms in relation to age was quite similar, which may indicate a shared etiology. The prevalence of headache and facial pain among women peaked in 25- to 44-year-olds and was observed to be at lowest among the 65-year olds and older ages (Von Korff et al. 1988). A trend of continuing decrease in prevalence of TMD related symptoms in elderly has also been observed (Carlsson et al. 2014); 80-year-olds reported lower prevalence of such symptoms than 70-year-olds. These observations of declining prevalence of pain conditions from approximately the age of 60 and onwards are interesting in relation to the understanding of the phenomenon pain. Changes in levels of sex hormones after menopause (Fillingim 2000, Cairns and Gazerani 2009), changed stress levels and related behavior have been offered as explanations (List et al. 2001) but there may be other reasons. Future studies specifically addressing elderly and their beliefs about why pain conditions may decrease with age might help to generate new hypotheses on the subject. It is not inconceivable that differences in lifestyle between elderly and younger

DISCUSSION

52

generations of Sami women may account for some of the differences in pain prevalence. During the 1930s to 1950s, physical activity was a more normal part of the Sami daily life, than it is today (Nilsson LM. et al. 2011). Also a sedentary life in front of a computer constitutes a part of a normal weekday among many of the younger generation, which may constitute a risk factor for increased symptoms in the neck and, shoulders and for TMD (Perri et al. 2008).

The causes of age-differences are complex and probably related to both external and internal factors. Previous studies have shown that older TMD patients reported a greater negative impact on quality of life (John et al. 2007, Rener-Sitar et al. 2008) which supports the finding that despite age being significantly and inversely related to prevalence of TMD symptoms the estimated impact on daily life was not.

Co-morbid conditions

In this study on Sami women, significant relationships were found between

symptoms in trigeminally and spinally innervated regions. Those included in

the interview also considered the symptoms in the jaw-, head-, and

neck/shoulder region as more or less unified. These observations confirms

the results from previous studies (Wänman and Agerberg 1987, Schokker et

al. 1990, Hasvold and Johnsen 1993, Ciancaglini and Radaelli 2001,

Magnusson et al. 2000, Visscher et al. 2001b, Rantala et al. 2003, Wiesinger

et al. 2007, Marklund et al. 2014) and indicates that these conditions are

influenced by the same contributing factors and/or mutually affected or

potentiated by each other. Co-morbidity between headaches and TMD pain

has been observed already from the teen-age period of life (Nilsson et al.

2013). The lowest common denominator of these associations may be tooth-

clenching habits, which beside the Sami women’s narratives also have been

identified as a risk factor associated with frequent headaches in a prospective

study (Marklund et al. 2014).

Headaches and NSP are common symptoms in the population (Bovim et al. 1994, Göbel et al. 1994, Unruh 1996, Côte et al. 1998, Scher et al. 1998, Rantala et al. 2003) and in accordance to the observations of the Sami women. Women report pain more frequently in these areas (Andersson et al. 1993, Bovim et al. 1994, Unruh 1996, Scher et al. 1998, Rantala et al. 2003), and they also report a higher degree of related disability than men do (Bovim et al. 1994, Unruh 1996, Webb et al. 2003, Unruh 2008). The prevalence of frequent headaches among the examined Sami women was close to figures previously presented in women (Agerberg and Bergenholtz 1989, Rasmussen et al. 1991, Boardman et al. 2003, Rantala et al. 2003, Yekkalam and Wänman 2014a). The approximately 40% reduction in prevalence of headache that occurred when moderate to severe intensity level was added

DISCUSSION

53

as criteria resemble results presented in a previous study (Boardman et al. 2003). The prevalence of frequent (weekly) neck pain was lower in the Sami women than among 3055 year old Finnish women (Rantala et al. 2003), but higher than reported for a general population sample in England (Webb et al. 2003), and close to the prevalence reported in a Norwegian survey (Hasvold and Johnsen 1993). In a Canadian sample, the 95% confidence interval for lifetime prevalence of neck pain, among both men and women, was found to be within 64%70% (Côte et al. 1998). This was only slightly higher than among the Sami women in this study. Differences in how questions are constructed probably account for some of the variations in prevalence between the studies. Using the same questions, the one-year period prevalence of troublesome neck pain among women reached 40% in a Norwegian (Bovim et al. 1994) as well as in an Italian sample (Ciancaglini and Radaelli 2001). In the former study the prevalence was halved when only longstanding and troublesome neck pain was included. A pattern similar to that of the present study. When the criterion frequent (weekly), intense (moderate or worse) neck pain of at least five year’s duration and with a significant effect on daily life was added in an analysis the 95% confidence interval for prevalence of neck pain among women was 2.2%5.4% (Webb et al. 2003), a figure significantly lower than in this sample.

Even in adolescents neck and back pain, have been significantly related to TMD pain (Nilsson et al. 2013). The severity of pain in the spinal region has been shown to affect the prevalence of TMD symptoms (both pain and dysfunction) in a mutual dose‒response like pattern (Wiesinger et al. 2009).

Reciprocity has also been found between the incidence of spinal pain and TMD signs in a prospective study on university students (Marklund et al. 2010b). Furthermore, it has been reported that patients with chronic craniomandibular pain often suffer from NSP and spinal pain (Visscher et al. 2001b). The exact causality of the observed co-morbidity is not known. The functional pattern shown between neck and jaw regions during rhythmical jaw movements indicates a synchronized motor control between the jaw and the upper spine (Eriksson et al. 1998, Eriksson et al. 2000), with activation of both jaw and neck muscles (Häggman-Henrikson et al. 2013). Stimulation of nociceptors in the temporomandibular joint area in cat activated the fusimotor-muscle spindle system of the dorsal neck muscles, suggesting that reflexes might be involved in the pathophysiological mechanisms responsible for the sensory‒motor disturbances in the neck region often found in

patients with temporomandibular disorders (Hellström et al. 2002). In healthy subjects the temporal coordination between the neck and the jaw system is high during normal jaw opening‒closing movements (Eriksson et

al. 2000, Zafar et al. 2000), but hampered in patients with a whiplash associated disorder (Häggman-Henrikson et al. 2002).

DISCUSSION

54

Chronic pain in the head and neckshoulder region has also been associated with mood disturbances and perceived impaired general state of health (Linton 2000, Croft et al. 2001, Rantala et al. 2003, Bingefors and Isacson 2004, Carroll et al. 2004).

The present study showed that the estimates on the ADL scale for TMD symptoms was influenced by the intensity of neck pain, the estimate on the ADL scale for headache was affected by the frequency and intensity of feelings of tiredness in the jaws and the estimate on the ADL scale for neck‒shoulder pain was influenced by the reported intensity of tiredness in

the jaws. The individual’s cognition of the symptoms’ interference with daily life (which may indicate a higher state of severity) seemed to share a pattern of mutual impact similar to that between trigeminal and spinal symptoms. The results support previous observations on a relationship between neck disability and jaw disability in a sample based on subjects who attended a TMD/orofacial pain clinic compared to healthy subjects (Olivo et al. 2010). This study in Sami women thus gives support to the observations that symptoms in trigeminal and spinal regions are closely interrelated.

Casecontrol study

The reasons why women outnumber men as TMD patients are still not fully understood. Women may pay more attention to their health, and may have more sensitive perceptions of the symptoms, feel higher levels of disability and impact on social life, and experience the symptoms for a longer duration and at higher intensity than men do. Factors related to sex or gender may predispose or increase the vulnerability of women to developing

longstanding pain and dysfunction, in general, as well as in the jawface region, which has powerful proprio- and nociception. Polymorphism of catecholamine-O-methyl transferase (Diatchenko et al. 2005) and serotonin (Ojima et al. 2007) as well as differences in the haplotypes of β receptors (Diatchenko et al. 2006) have been reported to be related to the development of TMD pain. This, together with the role of sex steroids and psychosocial factors, have formed the hypothesis of biopsychosocial mechanisms and increased vulnerability of certain individuals to developing pain and dysfunction in the jawface region (Diatchenko et al. 2006).

The significantly higher BMI of the cases may indicate that obesity is related to TMD in women. High levels of estrogen have been related both to higher BMI values (Olson et al. 2006) and to TMD pain (LeResche et al. 1997b). The link may thus relate to female hormones, physical activity levels, or both, and warrants more research. Factors that induce increased physical loading on the tissues involved may be individually significant and related to the individual’s reaction patterns and capacities (Wänman and Agerberg 1991). One major difference between cases and controls with regard to clinically registered variables was the pain

DISCUSSION

55

elicited when loading the muscles and the TMJ. One of the first studies to find differences between cases and controls with regard to submaximal clenching was that of Clark et al in 1984 (Clark et al. 1984). The finding of pain reactions on TMJ loading may indicate that the prevalence of arthralgia was higher than indicated by the RDC/TMD classification schema, in which tenderness to palpation over the joint area is an obligate criterion. The cases also presented a significantly higher proportion of pain reactions to palpation. These signs are often interpreted as indicating myofascial involvement, although recent research indicates that they may be inferred as indicating a reduced pain threshold to pressure (Svensson and Arendt-Nielson 2000). No major differences in the state of dental occlusion or variations in the specific examined occlusal factors were observed between cases and controls. The result thus support the opinion that factors in the dental occlusion do not have a predominate role in the perpetuation of musculoskeletal symptoms in the jawface region. The results are in line with the results of most previous epidemiological studies, which demonstrate that a similar variability of dental occlusal factors exists among subjects with and without TMD (Carlsson GE 2010). Contradictory results have also been presented. Artificial interferences were attached to the teeth in TMD patients previously treated with positive outcomes, and in controls. The study showed that the patients were more vulnerable to develop symptoms and more sensitive to the change than the controls (Le Bell et al. 2006). Some factors in the dental occlusion were identified as risk factors for incidence and persistence of TMD in a prospective study (Marklund and Wänman 2010a). The authors of the latter study expressed that a too simplistic view of the dental occlusion may be harmful to the individual patient with longstanding TMD signs and symptoms. Studies investigating causation should have a prospective design. Further, well controlled, and prospective studies in the future may help us to decide if the “occlusal door” should be ajar or closed.

Persistent pain in the jawface region may be caused by a focal neuropathic pain disorder (Clark 2006). Idiopathic pain conditions in the face are bothersome for the patient and difficult to manage. It has been hypothesized that neuropathic pain disorders may be related to changed perception of tactile stimulation (Jacobs et al. 2002). The tactile thresholds in the trigeminal innervated regions were thus tested with von Frey monofilaments. The cases and controls, however, responded uniformly to the tactile perception test. From my clinic experiences, patients with severe idiopathic facial pain conditions can present signs of both hypo-, and dysesthesia in the painful region of the face. One interpretation of the result may be that the population of approximately 500 included women was too small to capture such cases. The prevalence of these conditions may thus be counted per thousand.

Women with TMD considered their general health status as more impaired

than that of the controls which supplements and confirms the results of

DISCUSSION

56

previous studies (Agerberg and Carlsson 1975, Johansson et al. 2004, Yekkalam and Wänman 2014b). The significant and high likelihood of reporting impaired health among the cases was interesting, since the proportion of those under medical care due to disease did not differ significantly between cases and controls. This result should not be interpreted a direct correlation between the experience of symptoms in the jawface region and impaired general health. There may be several confounders of the results, such as co-morbid pain in other locations, with related sleep disturbances (Lobbezoo et al. 2004) and psychological distress (Visscher et al. 2001a).

Thematic interviews

Experiences of TMD

In the interview a choice was made to display a variety of beliefs towards and experiences of jaw, neck, and shoulder pains from the Sami women’s non-expert perspective. All informants with TMD also had neck and shoulder pains, headaches and tinnitus, and described, expressed, and regarded all these symptoms as a more or less unified condition. The pathophysiological background of such perception may be attributed to convergence of trigeminal and cervical nerves in the brainstem (Sessle et al. 1986, Piovesan et al. 2003). The women without TMD, headaches and NSP contributed with their thoughts regarding triggering factors, strains, distrust, and reconciliation. Most triggering factors were described in terms of inflicted injuries, but behavior, heredity, and life circumstances were all proposed and fit with the biopsychosocial model (Suvinen et al. 2005, Gatchel et al. 2007,). The model could therefore be used as a model for shared understanding in patient information and treatment sessions.

Proposed causes of TMD

A common statement among the participants with TMD symptoms was that

they were aware of clenching their teeth together. Bruxism (tooth clenching

and/or grinding) is one proposed etiological factor of TMD. The participants

comprehended that their biting behavior was a cause of their TMD problems.

Several studies have found relationships between reported bruxism and

TMD (Glaros and Burton 2004, Svensson et al. 2008). This relationship has,

however, been questioned with reference to the weakness in self-reported

bruxism and analyses mostly based on cross-sectional samples (Molina et al.

2000, van der Meulen et al. 2006). In a fairly recent systematic review on

bruxism and temporomandibular disorders (Manfredini and Lobbezoo

2010b), the authors concluded that self-reported bruxism was associated

with TMD pain, but that studies using more specific methods to diagnose

bruxism showed weaker association with TMD symptoms. The present study

DISCUSSION

57

gives support to the existence of a relationship between TMD and tooth

clenching habits, based on the participants’ narratives and experiences. A

habit of long-term, low-level clenching (holding teeth tightly together) might

thus be a significant factor in the development of longstanding TMD (Glaros

et al. 1998, Glaros and Williams 2012). In the case-control study, the cases

significantly more often reported awareness of tooth clenching habits than

the controls. Even a light clenching effort, referred to a tooth contact habit

with the maxillary and the mandibular teeth continuously in contact with

minimal force in a nonfunctional situation (Sato et al. 2006), may cause

strain of the TMJ and masticatory muscles. A habit of maintaining tooth

contact has been noted as a risk factor for development of myofascial pain

(Michelotti et al. 1997, Chen et al. 2007,). The strain may cause injury of

muscle fibers and reduce the blood supply to the muscle since perfusion is

impaired during clenching (Kim et al. 1999, Buzinelli and Berzin 2001,

Svensson et al. 2001, Nakamura et al. 2005). One of the most commonly

reported symptom in the questionnaire study, was feelings of tiredness in the

jaws which may be an effect of habitual nonfunctional tooth contact activity.

The results are thus in line with previously found associations between oral

parafunctions and TMD (Magnusson et al. 2000, Jacobs et al. 2002,

Johansson et al. 2004, Marklund and Wänman 2010a), indicating that these

jaw motor behavior patterns, especially tooth clenching and tongue pressing,

are significant in patients with TMD.

Distrust in healthcare

The Sami women shared experiences of distrust of both medical and dental health care services. Similar results were found in a qualitative study of chronic orofacial pain patients referred to a pain clinic (Wolf et al. 2006). The orofacial pain patients, however, expressed anger and frustration and regarded their pain as elusive. Such strong expressions were not used among these Sami women. This difference may be related to differences in the explicit dental health care situations and related expectations. Participants in the orofacial patient sample also expressed feelings of helplessness and a need to be taken care of (Wolf et al. 2006). The Sami women, on the other hand, indicated empowerment in their self-management and coping strategies, and gave examples of factors that provided them at least temporary pain relief. Both of these studies, however, indicate that the consultations are a critical event, which at least among those with longstanding pain has not favored recovery and rehabilitation. In an article by Eccleston and co-workers, responsibility, blame, and identity protection among pain patients and professionals were unfolded (Eccleston et al. 1997). The consequence of not being believed, and questioned, severely damages the trust between patient and caregiver. Such experiences may even prolong the pain and are less likely to motivate the patient to adherence to suggested

DISCUSSION

58

treatment strategies. The consultation event thus seems to be a potential area for development among physicians and dentists. The caregiver should pay attention to the patient’s own thoughts and beliefs, since this could be a good point of departure in the rehabilitation process.

Health aspects

Most participants shared thoughts regarding the healing and reconciliation processes. For these women, good health was equal to, and a prerequisite for, independence and freedom. The ability to work was thus an important keystone, together with the vision of physical fitness. Access to nature was also important. The participants reported various types of physical activities such as walking, running, skiing, and taking part in group training. Exercise is also recommended as an important part of rehabilitation in patients with chronic pain (SBU 2006). A study from the north of Norway showed that ethnic origin had an impact on the level of physical activity. Sami women were more active than the Norse women (Hermansen et al. 2002). The results indicated a common understanding of exercise being an important part of a coping strategy to stay healthy. All people are probably, at some point of their life, subjected to various strains, related to physical, psychological and/or social difficulties. The ways people succeed in facing these difficulties varies. Despite similar level of strains, some manage to stay healthy while others do not. Some of the results from the interviews can be viewed from a salutogenic perspective as proposed by Antonovski, (Antonovsky 2005). His model focuses on people’s resources and abilities to resist adversities, maintain health, and cope with negative stressors. An individual's capacity to handle stress and diseases depends on the extent to which life is experienced as meaningful, manageable and understandable all important keystones in the concept of sense of coherence. The Sami women, described difficulties, strains and life stressors, but some obviously remained healthy. The women without TMD described a social context in which they felt secure and presented various strategies to cope with strains. They described a strong social support, in accordance to the salutogenic model. It has been reported that a strong sense of coherence is associated with better health-related quality of life and self-efficacy as well as less catastrophizing thinking in patients with chronic pain (Chumbler et al. 2013). It was further concluded that sense of coherence may be an important factor for patients with chronic musculoskeletal pain. Efforts to strengthen empowerment and self-efficacy in individuals with pain and dysfunction in jaw, head, and neck, may be fruitful for both the individual and the society. I thus consider further studies with salutogenetic perspectives important, to gain increased knowledge in factors of importance for maintenance of the good health.

CLINICAL IMPLICATIONS & FUTURE PERSPECTIVES

59

Clinical implications and future perspectives

My vision of this research project was to follow a path of discovery from the

answers in a questionnaire down to the individual perspective among Sami

women. The gender perspective was chosen, since women outnumber men

as patients with TMD, and the Samis, since available surveys were limited

when the project started, and because they may be regarded as a fairly

homogenous population. The latter assumption may, however, be

questioned. In general terms, the observed prevalence of conditions examined was briefly in line with other population-based studies conducted during a fairly similar period, indicating that the findings are not specific to the Sami women, but may be considered valid for women in general. The results support previous studies on TMD and its dependence on age, affect on quality of life, relationship to other pain conditions, and awareness of oral parafunctions among the affected. From the narratives it was evident that many of the women with longstanding pain in the jaw‒face region had been treated with bite splints,

but they were not quite convinced about the effect. Splints are today advocated as a treatment of choice, and their positive effect has been shown in several studies (Swedish guidelines for dental health care in adults). There is, of course, no universal treatment effective for all individuals, and perhaps the selected women were those who did not respond to previous treatment strategies. Splints may be viewed as a fairly passive and conservative treatment approach. If the patient is not fully motivated, her compliance with the treatment may be hampered. From these perspectives an approach by dental health care providers that includes active listening, confirmation, motivation, and individually adjusted information is essential to build trust and reconciliation and improve adherence to treatment regimes. The management should be supportive and enhance the patient’s empowerment and self-efficacy to handle stress and strain and to take active part and responsibility in the rehabilitation process. An understanding of the patient’s social context and support should also be taken into consideration. A multidisciplinary approach is advocated for more severe cases, since the women with longstanding and more severe TMD also were affected by headaches, neck‒shoulder pain, and tinnitus. The remuneration system for

treatments of these patients in dental and medical care should, accordingly, for this group of patients be the same. Future studies should try to find answers to explain factors related to the observed decline of TMD symptoms and headaches with age. Rehabilitation in groups may be tested in patients with disabling TMD to elucidate whether that context can improve a sense of coherence, self-efficacy, and coping strategies for the benefit of the patient.

SUMMARY OF RESULTS

60

Summary of results

This investigation among Sami women in Arctic Sweden showed that

Symptoms indicative of temporomandibular disorders, headaches and neck‒shoulder pain were frequently reported and showed co-

morbidity in a cross-sectional analysis.

The most commonly reported symptoms indicative of temporomandibular disorders were feelings of tiredness of the jaws and temporomandibular joint sounds.

The prevalence of symptoms indicative of temporomandibular disorders and headaches diminished with age.

Symptoms indicative of temporomandibular disorders, headaches, and neck‒shoulder pain influenced daily life negatively. Seventeen

percent of the Sami women reported some disability related to their symptoms indicative of temporomandibular disorders.

Factors related to pain had the greatest influence when these Sami women rated the related impairment.

The individuals’ cognition of the symptoms’ interference with daily life showed a pattern of mutual influence between trigeminal and spinal areas.

Longstanding, severe, and frequent symptoms indicative of temporomandibular disorders remained essentially unchanged over a two-year follow-up period.

In the examined cases, a diagnosis according to the Research Diagnostic Criteria for Temporomandibular Disorders classification was established in 59%, and 91% had signs of dysfunction according to the clinical dysfunction index.

An impaired general state of health was commonly reported among women with temporomandibular disorders

The state of the dental occlusion was similar between the TMD cases and controls.

Women with TMD symptoms expressed awareness of habits of biting/holding teeth together, and a limited social support.

CONCLUSIONS & GENERATED HYPOTHESES

61

Conclusions and generated hypotheses

Women are commonly affected by symptoms in the jaw, head, and

neckshoulder region. Both pain and dysfunction symptoms in the temporomandibular region are related to disability and interference with daily life.

Sami women with longstanding TMD symptoms related their symptoms to fairly simple triggers and a more or less consistent jaw-clenching behavior, indicating that relieving such behaviors and related strains should be an essential element in treatment of patients with TMD.

Co-morbidity between symptoms in trigeminally and spinally innervated regions may affect both perpetuation of symptoms and related disability. This indicates that in management of patients with such symptoms, pain and dysfunction in both regions should be taken into consideration.

Women with TMD, associated headaches, and NSP may benefit from empowerment of their self-efficacy to handle stress and strain and also to take active part in their rehabilitation. An understanding of the patient’s social context and support may, in that coherence, be crucial to the outcome.

An approach by health care providers that includes active listening, confirmation, motivation, and individually adjusted information may help to build trust, reconciliation and improve adherence to treatment regimes. Group rehabilitation may also be tried in patients with disabling TMD to elucidate whether that context can improve a sense of coherence, self-efficacy, and coping strategies for the benefit of the individual patient.

ACKNOWLEDGMENTS

62

Acknowledgments

Completion of this thesis would not have been possible without support.

Many people have been involved, several of them throughout the long

journey, others for shorter periods of time—but with equally important

input. A collective “Thank you” to all of you who in one way or another have

helped, supported, and encouraged me during all these years. In particular, I

would like to thank the following:

Professor Anders Wänman, my main supervisor and mentor, for always

believing in me during this long research process. You have, with great

patience, never-ending support, and a big heart, throughout the years

encouraged me to finish this thesis, although at times it felt completely

impossible. Thanks for so generously sharing your enormous knowledge in

the field of clinical oral physiology, both in research and in the clinic. You

have inspired me since I was an undergraduate student, and especially

during my specialist training and PhD studies. Your door has always been

open, and you have given me your time whenever needed. I am so proud of

having been educated and clinically trained by you and to continue to be part

of your research team. I’ll always bring with me your wise advice; bib!

Professor emerita Eva E. Johansson, my co-supervisor, for giving me your

full support in the qualitative part of this project, despite the fact that you

came in late in the process. Your expertise has been tremendously valuable,

and your wisdom has inspired me during our work together.

Kerstin Hägg, my former co-supervisor, for valuable advice and comments

regarding my test interviews and the interview guide, when planning the

interview study.

Professor emeritus Per-Olof Eriksson, for valuable comments on the thesis,

and for nice conversations about Kiruna, over the years.

Dr. Susanna Marklund, Head of Specialisttandvården, for valuable

comments on the thesis, great encouragement in my research as well as in

my clinical work, and for sharing your excellent clinical expertise.

Ewa Lampa and Dr. Catharina Österlund, my specialist colleagues for good

company, many laughs, and pep talks, and for sharing your clinical skills.

Ewa, my roommate, it feels like Kiruna is just around the corner, and that

feels really good. Hoja!

ACKNOWLEDGMENTS

63

Dr. Birgitta Wiesinger, and Dr. Birgitta Häggman-Henrikson, for valuable

comments on this thesis, for good company, support and for sharing your

scientific knowledge.

Ann-Sofie Strandberg, Hjördis Olsson, and Lillemor Hägglund for

administrative support.

Colleagues and workmates at Specialisttandvården and at the Department of

Clinical Oral Physiology, for being supportive and for providing a good

working environment. Special thanks to my former boss, Eva Utterberg, who

always tried to do the best for me, trixing and fixing with schedules and so

on. Good luck with new challenges!

The Public Dental Health Service in Kiruna, Karesuando, and Gällivare, for

letting me carry out the clinical examinations there. Special thanks to Bitte

Lindgren, my former boss in Kiruna, for invaluable help when scheduling my

research time.

Lars Holmgren, Fredrik Wiklund and Hans Stenlund for statistical advice

and guidance.

Humbly, thank you to all the Sami women who participated in the study.

Without you this thesis would not have been possible. A special thank you to

the women in the interview study, who so openheartedly shared their life

experiences.

Professor Mikael Svonni, my uncle, for translation of the abstract into North

Sami, and for good dinner company when you were working in Umeå.

Marie Enoksson, at the Sami Parliament, for always, both at work and

privately, answering my questions about one thing or the other.

Anna-Lill Ledman and Charlotta Svonni, at the Centre for Sami Research, for

fruitful discussions about ethics in research involving Indigenous peoples.

Charlotta Svonni, my dear friend and cousin, for tremendous support, pep

talks, and fruitful discussions about everything in between heaven and earth.

And not forgetting all the excellent dinners, whenever needed, especially

when I was away from home during my specialist training. Lotta, I do not

think there is anyone outside the field of clinical oral physiology who knows

as much about TMD as you do, and I promise from now on, to be all ears

about the history of the nomadic school, until your defense of your own

thesis.

ACKNOWLEDGMENTS

64

Relatives and friends, thanks for just being there, keeping me in touch with

the world outside my project. Special thanks to Annika Josbrant and Annette

Svonni, my cousins (“big sisters”), for always having been around in my life,

with love and support.

My extended family, the Mienna family, for all the pleasant times together.

Next summer I promise to participate in more activities. Special thanks to

Máhtte for all “emergency” computer help.

My dear parents, Ingrid and Olav, for all your love and consideration.

Without you, neither my specialist nor my PhD studies would have been

possible. Thank you for all the support and help, for me and my family,

during all these years, with everything from household chores to carpentry

and childcare, and freezers full of meat, fish, and berries. Having moved to

Umeå certainly has some drawbacks!

Thorbjörn, my big brother, who has always taken care of your little sister.

Thanks for your thoughtfulness, your wisdom, your bravery, and your advice

in big and in small. Thanks to Jennifer, for friendship, and language advice.

Thanks to Molly Grace and Jackson, for hugs and laughs, although the hugs

are fewer the older you get. Love you all and miss you always. The USA is too

far away.

Alexander and Ole, the guys in my life, for your endless love and never-

ending support, and for putting things into perspective. Thank you, Ole, for

having taken so much responsibility at home, but from now on I will give you

more help. I promise both of you to be more present henceforward. Thanks

for giving me so much happiness and joy in life. Lucky me, for having you!

This work was financially supported by: Department of Odontology, Umeå

University; Västerbotten County Council; Norrbotten County Council; The

Sami Parliament in Sweden; Visare Norr/Northern County Councils; Göran

Gustafsson Foundation; Stiftelsen JC Kempes Memorial Fund and the

Swedish Dental Society.

REFERENCES

65

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