i

Association between craniomandibular disorders andocclusal interferences in children

P. Kirveskari, Dodo!t,. P. Alaren, DOdont, DSocSci,b andT, Jnmsà, DOdontcUniversity of T\ùku, Institute of Deltistry, T\rrku, Finland

Thê assoclatiotr boteeon clitticd rigls of cradornandibular disorders (CMD) andocclusal ittterfe.eDces wae studied loDgitudi.Dslly iù two cohort! of childreq 5 ald10 yesrs ol ago at barolilo, reprerenti.g the ltolrpâtieDt poptrlrtior, They wersfollowed up tor 6 yoarr. Ths rân8ê of ectivo pôlticiDâùte wie g6 to IOA i! thsyounger group, otd 84 to Z4 in the oftler groop. Tho .ubjlcts werê ,eêtt Àùuallyfor rogistratiott ol siats ol CMD and for the prerence oi iatorferor|cer, ald for 8roal or phcêbo occlusâl rdiu.tnolt. The doubte-bltDd etuaty dêrign FaE.pplisal,Baroliro dato showsd lro arsociÂtion bstwoen tho vâriablee atudieà; parte of dataftoD secord ond thlral erâEinrtiols diecloeod sigliôcart associaiiÀs; ana fourtl,fifth â!d .irth ênminations diaclosod a coneistent pattera of sigiiÀcaot aeeocia_tioDs. (.t PRo8r,.trar DBIT 1992SZS92-6.)

I he signifcance of occlusal int€rferences iD theetiology of craniomaudibular dirordere (CMD) has beenquestioned iu numerous recent articlea.L? On the otherhand, contrasting fiadingig regarding .igt " 8nd symptomsof CMD aad various ocalusal factors hEve also beenghown"&r? A recent textbooklS regards occlusion ae impor-tsDt in deltal thenpy, but regarda the notion that occlu_siou is etioloaic in CMD development as far from compel-ling.

Proponents of the psychophysiologic theory of temporo_mardibu.lar joint dyafr:action maintain tùat occlueal fac_tors eitber hare notbing to do with the sigD.s and symptomsof CMD,le or elee occluaal changes found associat€à witÀCMD are I result of CMD mther thaa a causo of itmMoreover, the high ftequencies of sigr:s of CMD ag well asreported nalocclusion are regarded ar misleading by Greeneand Marbach,lg who argue that taany of the variables reg_istered represent Dormal variation.

There are several theoretical pitfalls in drawing conclu_siona on the etiologic role of occlugioa from studiee of a8_sociations.u A lack of association between signe of CMDand occlusal factors i|r cross-sectional studies does not ex_clude occlussl factors fron the etiology of CMD. NeitÀerdoes an existing a8sociation prove that occlusal factors have

PrcsentÆd at the A.hericaD EquilibrâtioI Society Meeting, Chi_cago, nl.

Supported in part by the American Equilibration Society.'Associâte Professot, Departhent of StobatogDathic ph]"6iology.DAssociata Professor, DepùtBeDt of Community Dentistry,cAesiatant Profeaoor, DepartDent of Olal DevelopEeltt and Orth-

odontics.tontgdga7

692

an etiologic role. The present study eramiues the associa_tion between occlusa.l int€rferences and signs of CMD overa period of 6 years in two cohortr of children, half of whomuaderwent occlueal adjustment annually.

SUB;'ECTS AND METIIODSAll cbildren 5 or 10 yearr of age ia the township and ru-

ral mrmicipality of Loimaa in southwestærn Fialand wereinvitæd by means of a lettc! to thei! parents to participatein this etudy, which had been approved by the EthicsCommittee of the District Hospital. A cohort of l5-year-olde was also included, ae reported earlier.r? Bas€li[e dataartd details of methode have been previouely reported,2rand are only brieûy reLatcd here.

Tbe total number of 5-year-olde was 186 (69 bove and 6lc;uls). Of these, 128 (6? boys and 6t gùle) volunteered topafticipate. The corresponding figures for lO-year-oldswere 116 (62 boye and 5,1 girls) and 109 (55 boye and 54girlg). At the firet eramiaation, one child was ercluded be-cause of a severe general health problem, etd ûve othenbecause of poor cooperation. Children receiving or havingreceived orthodontic trestment ale elcluded from thepreeent analysis. During the 6 years of etudy, 26 childrendropped out, and in a few cases the recordingr proved in-complete. Thur the analysis was based on a tot€l numberof children varying between 96 and 106 in the youngergroup and between 64 and 74 in the older group,

Tbe annual clinical examinatione were caried out by oneand the eame author (TJ) throughout the etudy, whoremained unaware of whether occlusal adjuetment hadbeen performed or oot. The eramination iacluded obser-vations of muscle and joint palpatory tenderness, jointaouade, and Beaaurementa of mandibular mobility. The

I

I

MAY IEO2 VOLUME 6? NUMAER 6

, CMD ANI OCCLUSAL INTERFEI.ENCES

12

l0I

0

11

VBLYEAR OF STUOY

Fig. 1. Changes in percentage of subjects totally free from occlusal iDt€rferen€€s in an-nually-adjusted arld placebo-adjuatcd groupo. B-L, Baseline.

last etamiration ir the eequence wal occlusal analysi.s il-cluding measurementa of retrusiv€-iDt4rcuapal positiou(RP-IP) dieta.nce, observations of 6rst contac't on hingeclooure, of the presence of mediotrusion coutacte, and ofpostcaliDe laterotlusion and pmtruaion contactr.

I-'nediately aftær the e-nmination, tùe children under-wEnt eith€r real or mock occlusal adjustment, as dot€r-mined i! adv&ce, by applying random numbers to alpha-betical lists of eubjects. The aqiustnsnt followed the prin-ciples of Daweonz and Riise.æ llle adjuatment wag doneonce a year in a marimua time of 30 minut€s. The mockadjustment wae performed in an identical eettiug; however,only nonabrasive bure were used.

The asgociatione between CMD and occlusal interfer-eDcea were anelyzed using the pres€Dt-absent dichotoEyfor CMD. The number of interferences denotes the tJpe ofinterfetence, not the number of teeth interfering. Thus aninterference-free occlusion had to diaplay the perception ofbilat€ral contact iJr the RP. a marimrm distance of leegthan I mm sagittâlly and vertically between RP and IP, noviaible lateral conponent of the slide RP-IP, no mediotru-Bion contacts, and no postaanine protrusion contacts. Lat-erotrusion contacts were not used in the present anallæisbecause of the di6culties in assessing them in the mireddentitions.

The chi equare test was used for Btatistical analyses.

RESULÎSThe impact of the annual adjustment on occlusion, ae

inepected 12 months sfter the adjustment, was small on theindividual level. It was impossible to distinguish betweenthe adjusted and nonadjusted subjects witbout a thoroughexamination of occlusal surfaces for traces of ginding.However, some evidence of a reduction in the number ofinterferences rvas present. Thus the number of subjects to-

TIIE JOURNAL OF PROSTTII]TIC DÈNTISTRY

tally free from iaterferences tÆnded to be g:eater in the ad-juetæd eroup tban in the nonadjuetcd group (Fig. 1).

The associatioa between the number of interferencesard the presencc of signa of CMD i8 pr€serted ia 2 x 2contingency tablee year by year for both cohorts and fotpooled cohorte (Table I). Baseline data showed no associ-ation, parts of the second and third year show 8i8lific$ttagsociation, and fourth, ôfth, arrd eirth year data ahow sig-ni6câtrt association in a consistent patt€rn. The sa.Eepatt€rn wss pre8ent in botb seres wheo analyzed sepa-rat€ly,

Contrarting the extremes of variation (two-point de-sign), the total material yielded a rtatirtically 8igai6cantassociation in tbe 6rst year of data collection. The associ-ation was strong iD the sûth-yeat data (Table II).

DISCUSSIONSeveral methodologic probleme typical of clinicgl etud-

iee have a bearing il the iùterpretation of results, RÆpeat-ability of the clinical procedures, symptom Suctuation,possible shifts in tooth position associatad with adjust-ment, shedding of deciduous tgetù, and eruption of per-manent teeth are eramplee of factors affecting the observedreeults, However, in view of the double-blind design of thestudy, the possible biasing effect of these factors wouldrather give rise to a false negative than to a falE€ poBitiveresult.

On the basis of the reeults presented ia our earlier reporton 15-year-olds, we suggested tbat the lack of associationbetween interferences and CMD in cross-sectionsl atudieemay be ascribed to methodologic reaaona.lT For a mean-ingful statistic€l analysis of aasociation, suficient vadationmust be present in tbe study populatioD. We submit thatthe variation in interferences ig insuficient unless specialmeaaures are taken in collecting data. Random samples of

OCCLUSION ADJUSTEDOCCLUSION NOT ADJUSTED

693

XIRVFSXANI, AI.ÀNEN' ND JÂMSÀ

T6blel.AssocistionbetweennumberofoccluealinterferencesandclinicalsigngofCMDintwocohortsofnonpatientchildren eramined annually: Chi square æ" ::::

Ags grouP 6 Yr Â8ê gro$P lo Yr

No. ot PrescDtPretêDlYeâr

7

NS1

14

P = 0.0141022

NS4

p = 0.00oG

P = 0.00dt329

P = 0.001

18n

NS

25NS

1135

p=00351639

p = 0.007511

E

2L

102l

6968 26

,110-34-6

0-34-6

0-34-6

0-34-6

40

32

26

3618

5716

0-3,t-6

0-34-6

3l40

31 011 t7

P = 0'006'l

6257

7

IIO

102l

13p = 0.00i

p = 0.o2

p = 0.043

45 50p = 0.000002

1850

p = 0.000082350

p = 0.00006

2at2

DO

38

312{

Table tI. Dishibutiotr of clinical 8i8ns of 9Ùq "t.JJÀilt -a * "nd of studv in auboarnples showing

ioJ nunLr and xigt' nunber of btærfcrences . -

Br, Ba!.line; NS, not stlticticâ[v 'isnif'ÙL

it o-p"i"t a""ig"tiCoborts pooled, chi 8quâre tÆst

8ttil. ol CMDNo. ot

btottatGlcGt

inc association w8E present only aftrr inttrveDtion i! tbe

*iJ ti is-t"--"rL reported previouslv'r?--O"" J*U"" t" t"y to introduce ths rnissing part of t'he

tJi-rioi-,Lt l" ""tlects not erpo€ed to t'he presumed

Jt i.*t-r", -anageable samplea by way of occlusal

JjïÀent, sas baged on t'he fact thÀt ws could foresee no

sieEiûcant harmful effectr'"*Dtttff;6y""- of study, a few subjects mentioned

oi""iro"Js h-"ient senBitivity in tÀeir t€€th aftet the

*i*J"ail-""" One gbl refured to pesent herself for

ii" "ittU "ra-lt"rion unless we pronised not to Srind ber

i*rl. SL n"a ""p"rienced

a lengthy period of sorenesg in

i""Lî """1 tit" after we had ground them' we did as

"u" Jlï, "t"--a her, and reassured her t'hat her tceth

;;;il':;n;* condition' She beloneed to the placebo

tt*-."i*"o, * did most of those who mentioned hav-

ing erperienced dentâl symptons after the adjustment' We

""i"r,i.r" ti" virtually no barmful efiects detectable in

ii"t"t "t"-itt*iong could be found in subjects who un-

l"*"it tl" *"ft""f adjustmerL Sinilar conclugions bave

JI-ùî nt"*""a bv others'z'% In general' tbe placebo

*it-"of -"" alao harmleEs etcept fot the few subjects

developing traneient subjective symptouts'- il" otà"t *"ay is a powerful t€st of at lesst two pet

*^-J"t" p"t e"ttard by the proponents of the psycho-

llîi"f"À'û".ry. If the variablee etudied-occlusel itr-

Li"t".Ë" *a "{* of CMD-for the most patt at least

Pre.cDlYear

0'1BL 5-ô

0-1u u-u

22311 24

P = 0'028B7

39P = 0'0001

AbbFviatiou a' i' Table I'

normal poputation must be very lÛge b€fore the numbet of

auUi""a__ ôt"a""ti"g abs€nce (or low occurtence) of intær-

ferencea becomes sdequat€ for statistical purposes'.'îrri*"*t .r ,ne two-point derigD is meaningful and

oftæ'n'more fruit than including the whole distribution iD

inlJt**, * "o"-" bv Solberg et at'E However' in stud-

i'"-r-*"ii"g "f

itti""f exsninations' the sanple sizes tend to

t"."it ,"t "-Jr ** re8p€ct to the ob€erved frequency of

;;;;t"*" or minimal presence of interferences' whileiil" "t"*", a"*

"Aded a significant association in pooled

"iii* "t"" U.fàr" intervention (Table II), a correepond-

694MAY IOO2 VOLUME 07 NTJMBEB 6

, , c]\,o AND occ.LUs^L TNTERFERcN@S

represent normal variation,re one must predict that areduction in "intærferences,' will have no syst€matic effecton the distribution of the .,Êign8" of CMD. Our result€ wereat variance with that conclusion.

The main argu.Eent concerns the very existcnce of theas8ociation between these interferences and CMD. Oneview is that the association only erists in the minds of cli-nicians.re Another view i8 that eventual occlusal changescsn emerge as a reault of CMD.æ Accordingly, art associa-tion could be present in patients but not in nonpatientpopulatioru. Again, both ofthese views are at variarce withour results. Our samples represented a young nonpatientpopulation.

The frequency of the separate clinical eigns was in een_era.l too low for a stati8tic€l anatysis of association. ônlvmuecular t€ndeme8s w8s t€et€d separat€ly and was fouaàto be asEociatêd with the number of int€rferences. inaccordance with the pattern present for any clinical sierrrepresentùrg CMD. Selignsn and pullingerr6 demonstrat€dsignifcant associationg between occluEal factors and tem_poromandibular joint (TMJ) dieorders but not with mval-gia- We suggest that the link between occlusion a.rld mval-gia at a relatively early age ahoutd aleo be considered wienhypotheees on the etiology of CMD are discuseed.

Out results do not really address the causal question. Thenumber ofocclugal interferenceE a.nd clirdcal eigu of CMDare ctude vadables. However, interferences appear to be

, part ofan effective caueal compler that enables dieclosure,i of the association. It i8 of particulat int€rest that a recantlv

introduced occlueal veriable, the difference in the number. of occlueal cont€ct8 between light ând hard pressure,26... could be efrectively applied to the analyeis of a.ssocia-\ions.u 'a Clearly, occlusal adjustment afiects not only the

number of interfereuces but also many other characteris-tics Euch a-s size, tlpe, location, alrd any combination ofthese. But even if we do not know what exactly conetituteethe efrective câusal compler, out results appeat to contra_dict the Irgument that an eventual association can onlv re-flect the effects of dysfunction on occlusion.

It is sometiDtes possible to deduce the predominant or-der of the appearance of the presumed cause and eftect inrepeatæd cross-sectional studies of one and the eame eal!_ple. In our samples, the shift from having interferences butno sigas into having both interferences ancl signs of CMDwas far mole common than the shift from having signs butno interferences into having both. That wou.ld eeem to fa-vor the order ofevents in which interferences precede sig:rs.However, the small number of subjects showing no inter_ferences precludes an effective analysig.

Helkimo2g considered occlusa.l factols to be important inthe etiology of CMD, although he found little support forhis opinion from the epidemiologic literature. In theabsence of convincing evidence, Carlsson and Droukasedeemed occlueal factors to be at best of little importance,

Contrary to the conclusione of those authorsls who do notregatd occlusion as playing a significant role in CMDdevelopment, we interpret our result€ a8 8uggesting a needfor reapprai8al of the role of occlueal factote in the etiologyof CMD.

CONCLUSIONSWithin the conter of this research design and the dura-

tion of this study, tùe following conclusions are drawn:1. Occluaal adjustment resulting in a modeEt deqeare in

the number of occlusal interferenceg waa euftcient to dis_close a eignificart aasociation between the number ofocclusal interferences ond clinical eigns of CMD in twononpatient child populatione.

2. The concept of "occlusal int€rference " as employed inthis study appeats to iaclude elements of pathophysiologicsigniûcance- Occlusal interferences are therefore unlikelyto repres€nt only normal variation,

3. The clinical signs of CMD used in this etudy, or atleast some of them, cannot be regarded as representingnormal variation if the êrm is rmderstood eo that onlvvariables beyond its liEits caD have alything to do with thedevelopment of pathofuaction.

4. The elimination ofanatomicslly minor occlusal inter_ferences does not entail harmfirl effects.

We thaol the District Health Autàoritiee of Loimaa, Fintand,for p€rmissioD to csrry out our study iD tùe local healtù centet, anjDr. Aino Nummila and the petsonnel of the health centei forpractical assieta.:rcc.

REFERENCES1. Rieder CE, Martiroff JL 1tl€ plevâIence of hsndibùld dysfunctioLPart II. A Dultiphâlic dl,sfunction pm6le. J pRosrrlEr DEÀ"r

1983:m:87-4.1.2. Drouhs B, Lhde€ C, Cad!.o! cE" R€lationship bet瀀D occtulal fac-tæ and sigD! and symptoDs of Esndibu.lâ! dysfu.nctionr. Acts Odon.

tol Sc{nd 1984;42:2??{9.3. Bu8h FM. Malocclulion, Eâsricatory huscle srd t€mporoE rndibularjoint t4nd€rnês- J Dent Res 1985;64:129-88.1. Liebe.nan MA, cazù E, Fuchs C, Litoô p. Mândibulâ, dysfurction in

10-1&year-oldr a! relatad io EolpholoAic matocctu3ion. J Orâl R€habil1985;12:209-1,û.

5. De I,aât A, vln Stleubêryhê D. Occlu!âl Elationlhip€ s.nd t€rDpom-Eândibular jobt dysfùnctioD- pâlt U. CoEelâtion b€twê€n occlusâl andariiculâ! pa!âmet€rs and slDpt Es of TMJ dysfunction by m€a[! of8t€pwile logistic regres€ion. J pRosrHÊr DEN"T l986t55:lt6-21.

6. S€lisDan DA, Pùllinger AG, Solb€rg WX. The prevÂlence of dentâl at_trition ard its $€o.iarion wit_h factals ofâge, sender, occlusioD ,.nd TMJrynptomatology. J Ded R.s r98a;6?:rBæ-BB.

?. Selighân DA, Puttinser AG, Solberg WK, Teoporobândibular dilor.de!s. Part III Occlu!âl ând &ticular fact rs alsociât€d with nus.tetendem€ss. J PRosTdEr DENI 198a;S9:4gl]-9.

8. Solbels WK, Woo MW, Houst n JB. p!€valence of mandibular dys-function in youns adult!. J Am Dent Alsoc l9?9;98:2S-A4.9. I.scrva.ll B, Mobtin B, Thitander B. prevale.ce of sllÎlptoms of func_

tionâl distùbânce€ of tÀe nssticst ry syÉt?n of Swedilh nen. J OrslR€habil 1980i?:185,9?.

10. Lederbân KH, Clayt n JA_ R€st r€d occlusioru. parr U. The relârion-ship of clinical ând subjective syhproms to varyiDs de8re€â of TMJdysfùction. J PRosTHÊr DENI 1982;47:A03-9.

THI: JOUI'NAL OF PTTOSTIIETTC DINIISTRY

IOIVISXATI. ÂLANEN. ItD JÂMSi

t1.

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15.t)<I ta.(

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Nilne! M. Relationship6 between orsl pârâfùncrioN and functionaldisturbancæ and dileales of the stonatograthic syst€d âmon8 childrenaaed 7-I4 ypÆ!. Act Odoùtôl ScâDd l98i];41:r6?-72.Nilner M. tulation.hips b€tween oral Frsfunctions 6Dd ÂDctionrldi.sturbaDcc€ i.n ths stonatoSlathic sr€t€m aûron8 15- to l&yëâr-olds.Act{ Odontol Sctùd 19tB;41:197-2Or.Esernark-Edl!Êon I, Ingervall B, Carlsson GE. The d€p€ndencs ofnandibul& dysfunction in children on fuDction.l âùd morpholosicInâlocclÙ8ioD, Am J Ortùod 1983;83:187-9.1.Esenûarl.Erilcgon I, C,rl$oD CE, M6€rulson T. A lonr-t2rb epide-Eiolosic study of tho ElotionÂhip b€ts€en occlulsl factoE aÀd rû.n-dibùlâr dystunction ir chilùen and adolêsc6nts. J Dsnt R.r 198?;66:6?-71.Pulinser AG, S€ligmân DA, Solberg WK. Tempoom&dibulsr dilor-ders. Pan n. Occlu!âl factôr' $socisted with trnpoloDandibular jointterdemess and dFÂDction. J I'RosnrEr DÊlû 1988593€$7,Seli$llsû DA, Pultinser AG. tusocirtion of occlùssl vadable€ â.Eongrecned TM p{tiênt dirSloètic group6. J Crt[iomandib Dilord FscislOral Pain 1989:3:2t-3€.Kir1,s6l(!ri P. Alanrn P. J&n.d T. Association betF€o! ûariomârdib-trlâr dilorden qlrd occlulsl iÀtrdoEncÉs. J PR6ncî DÈlrr198q62:6È9,Mobl ND, Z{rb GA, Cârllson GE, RùSh JD. A tartboot of occlusion"Cbicâgo: Quintés€aDcs Publilhiry Co, Iæ, r98&Gæene CS, Mûbacù JJ. EpidêDiologic !tudi"5 of nûdibular dyrtunc-tioù: a cdtical revi6w. J PRo6T HBT DÊNT 1982:4&18{-90.hslin DM. Etiology of th6 pai!-d)€functioD syndftne. J Am DcntAÈo. 1969?S1{7-53,Kilve€Lai P, Alâlæn P, Jôo!à T. Fù.bctional stat! of thô stomatog-uâthic lysttD in 5-, lG !Àd l5-y€'I-old childr€n in louthresto.û Fin-lâ[(l Proc FiDn Dent Soc r986i82:3-&

Dawlon PE. Evâluation, diagnooi! alrd trearbent of occlùsâl probl€lns.2nd ed. St. lrui!: CV Mo6by Co, 1989.Rib€ C. Ratjonrl Dedonnânce of occlusâl sdjùltûrenl J PRosnrETDEr!"r l9a2i{&319-27.Rrnfjord SP, tuh MM. Occlùsion. ârd êd. Pbilad€lphir: WB SaurdorsCo, r9$.Kirveslâri P,Ir Beù Y, Sâlon.n M, FoIs eU H, crâ.s L Efiecr ofelin-ination of occlusel int€.ferenceâ on signs and symptôms of craniomar-ôbulù di.o!de. i! younA adult!- J Orâl Rêhabil 19&*16:2r-ôRii!€ C. A clibical study of tbê Dumber of occlu!âl tôoth contrct! in theinærcu.pal position ât light âlîd bard pre€sùe in âdrntr. J Oral Rehabil19819;469-?7.Welll'1ân A, Asêrb€rg C. R€curlent headacheÊ âDd cralionandibùlâ!dilolde'3 i! adol€.c€ntâ: a lonaitudinal .tudy. J CraniohaDdib DisordI'âcisl Oral Pain 1987;1:229-36.Wà!6!n A, Àg€rbels G. F tisue iD thejap!: ô longitùdhrl6tudy in ad-olêscènt€. J Craniomandib Dirord Facial Oral Pain 198&2:æ-3t.Helkino M. Apidcniologicr.l surveF of d)€function of the rnâlticatolysy.têû. h: Zûb CÀ Carls€oD GE, ed& TebporoE!ùdibrirt jointtunction ùd dlrtunctioD- Cop€nhrg€n:.Mudr!8âatd, 1979:17S92.Cùlslon GE, Droùlù BC. Dentd oc.lulior .Dd tb€ heslt-h oftho Eâr-ticttary syÊt m. J ClrÀioEandib P.act f984*U1-7.

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MAY T9O2 VOLUME (t7 NUMBEN 6