ORIGINAL CONTRIBUTIONS

Approximal and occlusal cariouslesions

Restorative treatment decisions by California dentists

ABSTRACT

Background. Investigators use questionnaire surveys to

Peter Rechmann, DMD, PhD; Sophie Doméjean, DDS, PhD;Beate M.T. Rechmann; Richard Kinsel, DDS; John D.B.Featherstone, MSc, PhD

evaluate treatment philosophies in dental practices. Theaim of this study was to evaluate themanagement strategiesCalifornia dentists use for approximal and occlusal cariouslesions.Methods. In May 2013, the authors e-mailed a ques-tionnaire that addressed approximal and occlusal cariouslesion management (detection and restorative threshold,preferred preparation type, and restorative materials) to16,960 dentists in California. The authors performed ac2 statistical analysis to investigate the relationshipbetween management strategies and respondentdemographic characteristics.Results. The authors received responses from 1,922(11.3%) dentists; 42.6% of the respondents would restoreapproximal lesions at the dentinoenamel junction, and33.4% would wait until the lesion reached the outer one-third of dentin. The preferred preparation type was thetraditional Class II preparation. Dentists who graduatedmore recently (20 years or less) were more likely to delayapproximal restorations (P < .0001); 49.9% of the morerecent graduates would wait to restore an occlusal lesionuntil the outer one-third of dentin was involved, and 42.6%would restore a lesion confined to enamel.Conclusions. There is wide variety among Californiadentists regarding their restorative treatment decisions,with most dentists restoring a tooth earlier than the liter-ature would advise. More recent dental graduates weremore likely to place their restorative threshold at deeperlesions for approximal carious lesions.Practical Implications. Clinical evidence shows thatnoncavitated carious lesions can be remineralized; there-fore, early restorative treatmentmay no longer be necessaryor appropriate. Noninvasive and minimally invasive mea-sures should be taken into consideration.Key Words. Carious lesions; approximal caries; occlusallesions; diagnosis; decision making; restorative treatmentthreshold; California dentists.

C linicians increasingly have accepted minimallyinvasive treatment concepts.1-3 Decisions forrestorative treatment have been delayed towarda more advanced carious lesion stage.4

Caries preventive measures are more successful whenfrequently applied.5,6 Assessing the patient’s caries riskand assigning individualized preventive, nonoperativecare measures based on that risk have led to less need forinvasive operative treatments.7,8

Classifying carious lesions at a noncavitated stage9

could allow dentists to evaluate whether noninvasivemeasures would be successful.10 Noncavitated cariouslesions in enamel and dentin can be managed by meansof remineralization without restorative intervention.11,12

Monitoring topical fluoride application and pit-and-fissure sealants is considered the best practice accordingto the literature and should become the standard treat-ment modality for noncavitated carious lesions.13-15 TheInternational Caries Classification and ManagementSystem and Caries Management by Risk Assessmentrecommend minimal intervention treatment accordingto the patient’s caries risk level.10,16

Surveys in which investigators have evaluated therestorative treatment thresholds of dentists and man-agement strategies have been performed in many coun-tries and reveal wide variations. Those managementdifferences exist among countries and among dentistswithin each country.17-25

With the background of the success of preventive andnoninvasive measures in caries management, wedesigned this study to determine California (CA) den-tists’ restorative threshold for approximal and occlusallesions by using a Web-based survey. To our knowledge,this is the first time such a study has been performedin CA.

Copyright ª 2016 American Dental Association. All rights reserved.

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TABLE 1

Demographic characteristics ofcontacted California dentists andrespondents.CHARACTERISTIC DENTISTS

CONTACTED(N [ 16,960)

RESPONDENTS(n [ 1,842)

Sex, % n ¼ 1,786*

Male 68.2 68.4

Female 31.8 31.6

Age, y† n ¼ 1,756*

Mean (standarddeviation)

49.2 (18.0) 50.4 (12.2)‡

Years SinceGraduation†

n ¼ 1,816*Mean (standard deviation):

22.8 (13)§

More than 20 y ago Not applicable 753 (41.5%)

20 y ago or less Not applicable 1,063 (58.5%)

Type of Practice n ¼ 1,829*

Generalpractitioners

14,182 (78.4%) 1,600 (87.5%)

Specialists 3,896 (21.6%) 229 (12.5%)

Pediatric dentists 703 (3.9%) 108 (5.9%)

* Total number of respondents to this question.† At the time of the survey (2013).‡ Minimum: 25. Maximum: 73.§ Minimum: 1. Maximum: 53.

BOX

Survey*APPROXIMAL LESION (FIGURE 1)19

- Question 1: “The picture illustrates different radiographic stages ofcaries progression (approximal lesion, grade 1 to 6). Starting with whichlesion size do you think an immediate restorative treatment is required?In other words—pick the Figure number with the smallest lesion size forwhich you would not postpone restorative treatment under anycircumstances even if the patient has low caries activity and good oralhygiene.”- Question 2: “Which type of preparation would you prefer for thesmallest lesion you decided to drill and fill? (Imagine that the approximallesion is situated distally on the second premolar in the upper jaw.)”- Question 3: “Which restorative material would you choose for thesmallest approximal lesion you would restore?”

OCCLUSAL LESION (FIGURE 2)19

- Question 1: “The picture 2 illustrates different clinical appearances ofocclusal caries in a lower second molar (grade 1 to 5). Starting at whichlesion do you think immediate restorative (operative) treatment isrequired? Please, pick the smallest lesion size you think requires immediaterestorative treatment. In other words, that is the lesion for which youwouldnot postpone restorative treatment under any circumstances. The patient is20 years old, has low caries activity and good oral hygiene.”- Question 2: “Which type of preparation would you prefer for thesmallest of the lesions you decided to drill and fill?”- Question 3: “Which restorative material would you choose for thesmallest approximal lesion you would restore?”

CLINICAL CASE 1 (FIGURE 3)19

- Question 1: “Do you think that, from its clinical and radiographicappearance, the tooth has occlusal (enamel or dentin) caries?”- Question 2: “How would you treat this occlusal surface? You have notseen the patient before, and 2 years have elapsed since his last dentalexamination. The patient uses fluoride toothpaste on a daily basis anddietary and oral hygiene habits are considered satisfactory.”

CLINICAL CASE 2 (FIGURE 4)19

- Question 1: “Do you think that, from its clinical and radiographicappearance, the tooth has occlusal (enamel or dentin) caries?”- Question 2: “How would you treat this occlusal surface? You have notseen the patient before, and 2 years have elapsed since his last dentalexamination. The patient uses fluoride toothpaste on a daily basis anddietary and oral hygiene habits are considered satisfactory.”

* Adapted with permission of the publisher from Espelid and colle-ages17 and Tveit and colleagues.18

ABBREVIATION KEY. CA: California. DEJ: Dentinoenameljunction. GP: General practitioner.

ORIGINAL CONTRIBUTIONS

METHODSWe obtained approval for the survey study from theCommittee on Human Research at University of Cali-fornia, San Francisco (institutional review boardapproval 12-10135). We sent a Web-based questionnaireelectronically (May 2013; including an online consentform) to 16,960 CA-licensed dentists by using Survey-Monkey (SurveyMonkey). We sent an electronicreminder 15 days later. Table 1 provides the demographiccharacteristics of the dentists contacted.

Espelid and colleagues17 and Tveit and colleagues18

designed the questionnaire used in our study, and weused it with their permission (materials reproduced herepermission of the publisher). After users provided elec-tronic consent, the Web-based questionnaire assessed thestage of lesion progression at which the respondentsconsidered restorative strategies appropriate by usingdiagrams of different stages of approximal and occlusalcarious lesions. The survey recorded preferred restorativetechnique and restorative material of choice for treat-ment of these hypothetical lesions, along with the sex,age, year of graduation, and type of practice (generalpractitioner [GP] or specialist and the specialty).

For all questions, an imaginary 20-year-old patientwas described. This patient visits a dentist annually, haslow caries activity and good oral hygiene, and uses afluoridated toothpaste. The items of the questionnaireare shown in the box and Figures 1-4.19

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We performed descriptive analyses to characterizethe respondent population and the responses to thedifferent questions related to the management strategiesfor approximal and occlusal carious lesions. We used ac2 test to assess the relationship between the managementstrategies and some demographic characteristics (sex,years since graduation, and the respondents’ type ofpractice). We used subgroups for further analyses. Thefirst set of subgroups was years since graduation (20years or less versus more than 20 years ago). For thesecond set of subgroups, we merged grades for bothapproximal and occlusal thresholds with regard to clinicalrelevance. Merging occurred with regard to potentialtreatment options and likelihood of successful lesionremineralization. The approximal carious lesion

0

5

10

15

20

25

30

35

40

45

PER

CEN

TAG

E

2.9

15.1

42.6

33.4

42

1 2 3 4 5 6

GRADE

Figure 1. Approximal lesion restorative threshold. The figure illustrates different radiographic stages of cariesprogression. The example refers to the distal surface of a maxillary second premolar and answers the question“Starting with which lesion size do you think an immediate restorative treatment is required?” (See the Methodssection for more details.) Stages of caries progression: grade 1, lesion in the outer one-half of enamel; grade 2,lesion in the inner one-half of enamel; grade 3, lesion at the dentinoenamel junction; grade 4, lesion involving theouter one-third of dentin; grade 5, lesion involving the middle one-third of dentin; and grade 6, lesion involving theinner one-third of dentin. There were 1,833 respondents. Adapted with permission of the publisher from Mejareand colleagues.19

ORIGINAL CONTRIBUTIONS

restorative thresholdsubgroup was cariouslesions grades 1 and2 (merged) versus lesionsgrade 3 versus lesionsgrade 4 versus lesionsgrades 5 and 6 (merged).The occlusal restorativethreshold subgroup wascarious lesion grades 1 and2 (merged) versus lesionsgrade 3 versus lesionsgrades 4 and 5 (merged).

We performed the sta-tistical analyses by usingSPSS 19 (IBM). We set thelevel of significance at 5%.

RESULTSRespondents. A totalof 1,922 dentists (11.3%)replied to the Web-basedquestionnaire survey.Of these, we excluded80 respondents becausethey only answeredquestions related to theirdemographic characteris-tics. Of the remaining

1,842 respondents, 87.5% were GPs, and 12.5% were spe-cialists that included 5.9% pediatric dentists. Most of theremaining specialists were prosthodontists and ortho-dontists plus a few others who appeared to feel compe-tent to answer caries-related questions. Table 1summarizes the demographic characteristics of the CAdentists contacted and the respondents. Sex distributionand average age were similar for both groups; 9% moreGPs and 9% fewer specialists were among the re-spondents. In addition, 50% more pediatric dentistsparticipated than were accounted for in the group ofcontacted dentists.

Restorative management of approximal cariouslesions. Eighteen percent of the respondents suggestedrestorative treatment and would not delay treatmentunder any circumstances for a lesion confined to enamel(grades 1 and 2), 42.6% would not delay treatment fora lesion at the dentinoenamel junction (DEJ) (grade 3),and 33.4% would restore when the lesion reached theouter one-third of dentin (grade 4) (Figure 1). Thepreferred preparation type (54.1%) was the traditionalClass II preparation, and 45.9% of respondentspreferred a minimally invasive cavity preparation(tunnel or saucer shaped). Most of the respondents(92.6%) recommended tooth-colored material (resin-based composite, glass ionomer cement, resin-modifiedglass ionomer cement, and sandwich-technique glass

ionomer cement), 6.4% recommended amalgam, and1% proposed other kinds of materials (for example,gold). The preferred preparation type and the suggestedrestorative materials were reported independentlyfrom the reported treatment threshold level.

Restorative management of occlusal cariouslesions. Almost 41% of the respondents would restoreand would not delay treatment under any circumstancesfor a lesion confined to enamel (grades 1 and 2). One-halfof the respondents (49.9%) would restore an occlusallesion that involved the outer one-third of dentin(grade 3), and 9.4% considered a lesion in the middleone-third of dentin or deeper (grades 4 and 5) as thesmallest lesion requiring immediate restoration place-ment (Figure 2).

When asked about the extension of their restorativetreatment, 64.6% of the respondents would limit theircavity preparation to the carious area, 31.5% preferred apreparation including the whole occlusal fissure system,and 3.9% chose other types of preparation (for example,preparation for an inlay). Regarding the recommendedrestorative material, most (94.6%) chose tooth-coloredmaterials, 4.7% chose amalgam, and 0.7% would useother types of material (for example, gold, ceramic).Again, the preferred preparation type and the suggestedrestorative materials were independent from the reportedtreatment threshold level.

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0

10

20

30

40

50

PER

CEN

TAG

E60

3 4 5

49.9

GRADE1 2

1.8

38.9

7.7

1.7

Figure 2. Occlusal lesion restorative threshold. The figure illustrates different clinical appearances of caries.The example refers to a mandibular second molar and answers the question “Starting at which lesion do you thinkimmediate restorative (operative) treatment is required?” (See the Methods section for more details.) Stages ofcaries progression: grade 1, white or brownish discoloration in the enamel, no cavitation, no radiographic signs ofcaries; grade 2, minor loss of tooth substance with a break in the enamel surface or discolored surface or dis-colored fissures with gray or opaque enamel or caries confined to the enamel, no radiographic signs of caries;grade 3, moderate loss of tooth substance or caries in the outer one-third of the dentin according to theradiograph; grade 4, considerable loss of tooth substance or caries in the middle one-third of the dentin accordingto the radiograph; and grade 5, considerable loss of tooth substance or caries in the inner one-third of the dentinaccording to the radiograph. There were 1,813 respondents. Adapted with permission of the publisher fromMejare and colleagues.19

ORIGINAL CONTRIBUTIONS

Diagnosis and management of occlusal cariouslesions. Clinical case 1. The most common diagnosis(92.5%) for the occlusal surface of clinical case 1(Figure 3) was the presence of a dentin lesion, and97.2% of respondents would restore the tooth. Table 2presents the caries management alternatives for thislesion chosen by the respondents.

Clinical case 2. The most common diagnosis (50.5%)for the occlusal surface of clinical case 2 (Figure 4) wasthe presence of an enamel lesion. The respondents variedmarkedly in their diagnosis. Fewer dentists would restorethis tooth than in clinical case 1, but more than one-halfof them (56.9%) still would restore this noncavitatedlesion. Table 2 presents the caries management alterna-tives related to this enamel lesion chosen by therespondents.

Influence of type of practice and number of yearssince graduation on caries management strategies. Forapproximal carious lesions, the c2 test showed that re-spondents who graduated 20 years ago or less were more

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likely to suggest invasiverestorative treatment forlesions at a later stage(outer one-third ofdentin involved) thanwere those who gradu-ated more than 20 yearsago (lesion confined toenamel) (P < .0001)(Table 3). We also founda significant relationshipbetween the restorativethreshold for approximallesions and the type ofpractice: pediatric den-tists would suggest arestoration at laterstages of approximallesions than would GPs(P < .0001).

We found no signifi-cant relationship betweensex and restorative de-cisions. The managementdecisions for occlusalcarious lesions were notinfluenced by any of therecorded demographiccharacteristics.

DISCUSSIONInvestigators have stud-ied restorative treatmentstrategies by means ofquestionnaire surveysamong practicing

dentists in many countries (for example, Australia,26

Brazil,27 Canada,28 Croatia,23 France,20 Iran,29 Kuwait,21

The Netherlands,30 Scandinavia,4,17-19,31,32 Scotland,33 andthe United States24,25). Espelid and colleagues17 and Tveitand colleagues18 developed the questionnaire used in ourstudy, and it is the most commonly used, thus allowingcomparisons.17-20,22,31,32 We formatted the questionnairefor use as a Web-based survey.

The demographic characteristics of CA dentists in theoriginal database favorably compared with those of therespondents regarding the distribution of sex and age.When taking into account that nonrestorative specialistswho typically do not manage caries-related treatmentdecisions directly did not reply to the survey, the ratio ofGPs to specialists actually answering the survey appearedrepresentative. Because 50% more pediatric dentistsanswered the survey, we may conclude that pediatricdentists were slightly overrepresented in the response.

The response rate in this Web-based survey was 11.3%and thus much lower than response rates of similar mailed

Sound (0.4%)Enamel Lesion (4.1%)

Dentin Lesion (92.5%) Uncertain (3.0%)

A B

C

Figure 3. Answers to the question “For clinical case 1, do you think that, from its clinical and radiographicappearance, the tooth has an occlusal (enamel or dentin) caries lesion?” There were 1,808 respondents.A. Radiographic view of the tooth. B. Clinical view of the tooth. C. Practitioners’ answers. Adapted withpermission of the publisher from Mejare and colleagues.19

ORIGINAL CONTRIBUTIONS

surveys, which generallyachieved responsesbetween 40% and80%.17,19,20,25 Web-basedsurveys have lowerresponse rates. Rosenstieland colleagues34 in 2004surveyed 12,000 US den-tists about their molarrestoration choices andlongevity with a responserate of 6.3%. In surveys ofspecialists about specificsin their field, the responserate is generally higher,between 15% and 40%.35-38

The response rate inour study was similar tothe rate of dentists inOntario, Canada, whowere asked a detailedquestion about treatingteeth with apical peri-odontitis. When queriedabout their preference ofan endodontic treatmentor extraction withoutand with replacement byan implant, the special-ists answered at a 40%response rate on a mailedsurvey, and the GPsshowed a 15% responserate to the same Web-based survey.35

Restorative thresh-old. Studies in which the

investigators have surveyed dentists’ restorative thresh-olds reveal wide variations (Table 4).4,18-21,23,25-29 In somecountries, most dentists would restore approximal le-sions confined to enamel.20,27 In others, most dentistsrecommended treatment only when the lesion hasreached the outer one-third and the middle one-third ofdentin, respectively.21,25,29

In this regard, Scandinavia appears to play a leadingrole. For more than 16 years, the restorative treatmentthreshold has been high, abstaining from restorativeoptions until the lesion had progressed far into dentin.19

Results from studies in Norway also have shown thatadministering the same survey several years later resultedin the treatment thresholds that moved consistentlytoward deeper lesions.4,18

In our study, most CA dentists reported theirrestorative treatment threshold for lesions that hadreached the DEJ. One-third of the dentists wouldrecommend a cavity preparation and restoration for

a lesion extending into the outer one-third of dentin. Incontrast to this conservative behavior, almost 20% of therespondents would recommend restorative interventionat much earlier stages with lesions confined to enamel.This practice is not consistent with the literature andpotential remineralization and reversal of these lesions.

For occlusal lesions, fewer data were available forcomparison (Table 5).19-21,25,39 More than 40% of CAdentists suggested an immediate restoration for an earlystage of caries progression (grades 1 and 2). Almost one-half of the French dentists reported their restorativethreshold at the same level in 2002.20 One-half of the CAdentists decided to intervene restoratively at a moreadvanced dentinal lesion level (outer or middle one-thirdof dentin), and in 2012 the threshold of French dentistsalso had shifted to more progressed lesions.39 Similarlyfor approximal lesions, dentists in Sweden and Kuwaitreported their restorative threshold at even moreadvanced occlusal lesions.19,21

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Sound (19.1%)Enamel Lesion (50.5%)

Dentin Lesion (15.0%) Uncertain (15.4%)

A B

C

Figure 4. Answers to the question “For clinical case 2, do you think that, from its clinical and radiographicappearance, the tooth has an occlusal (enamel or dentin) caries lesion?” There were 1,796 respondents.A. Radiographic view of the tooth. B. Clinical view of the tooth. C. Practitioners’ answers to the question.Adapted with permission of the publisher from Mejare and colleagues.19

ORIGINAL CONTRIBUTIONS

As for all dentist surveys, one should keep in mindthat showing a picture of an occlusal lesion and sayingthat radiographically the lesion is evident in the outerone-third of dentin, for example, may have elicited amore aggressive treatment response than showingthe image alone, without a description. To be able tocompare the results of this survey of CA dentists withresults of surveys performed earlier and more recently inother countries, we decided to use an unchanged versionof the survey. This survey is more than 10 years old, sosurvey terms such as noncavitated were yet notintegrated.

Preparation type and material. When dentists decidethat a restorative approach to an approximal lesion isneeded, a minimally invasive removal of tooth structureshould be the goal. Whereas the tunnel-shape prepara-tion was not successful because of the obliterated view ofthe preparation field and recurrent carious lesions, thesaucer-shape preparation preserves tooth structure.40,41

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Practitioners have usedthe saucer-shape prepa-ration, a minimallyinvasive slot preparationwith extensive bevelsprimarily located in theenamel, successfully inlong-term studies.42,43

Most dentists in Nor-way and France indicatedthe saucer-shape prepa-ration as their preferredtreatment approach.4,44

In contrast, most of thesurveyed CA and Kuwaitdentists choose the tradi-tional Class II approach.21

Conversely, despite thisinvasive approach forapproximal lesions, mostCA respondents andKuwait dentists wouldremove only carious tis-sue for occlusal lesions.21

Notably, for the addi-tional clinical casesincluded in our study(clinical cases 1 and 2),most practitionersopted for restorative in-terventions over themore conservative sealantand treatment with fluo-rides and no treatment,respectively.

Although sealants arerecommended for non-

cavitated lesions,15 other researchers2,3 have demonstratedthat ultraconservative sealed amalgam and resin-basedcomposite restorations placed directly over frank cavi-tated lesions extending into dentin exhibited superiorclinical performance and longevity. Also, enamel-bondedcomposite resin restorations placed over cavitated lesionsarrested the clinical progress of these lesions for 10years.2,3 The restorative material of choice in all countrieswas tooth-colored restorations.

Today, dentists should know that operative dentaltreatment alone does not ensure oral health.45 In a 2012caries clinical trial,7 the investigators demonstrated thatplacing restorations in the control group did not reducethe mutans streptococci bacterial challenge significantlynor did placing restorations significantly change thecaries risk status. Only targeted antibacterial and fluoridetherapy based on salivary microbial and fluoride levelsfavorably altered the balance between pathologic andprotective caries risk factors.7

TABLE 2

Clinical cases 1 and 2: how would youtreat this occlusal surface?*MANAGEMENT STRATEGY CLINICAL CASE

1, NO. (%)(n [ 1,802)

CLINICAL CASE2, NO. (%)(n [ 1,774)

No Treatment 13 (0.7) 220 (12.4)

Fluoride Treatment 8 (0.4) 101 (5.7)

Sealant 30 (1.7) 443 (25.0)

Prepare Carious Part andRestore

351 (19.5) 219 (12.3)

Prepare Carious Part, Restore,and Seal Whole Fissure

962 (53.4) 539 (30.4)

Prepare Whole Fissure andRestore

438 (24.3) 252 (14.2)

* Not all participants responded to all questions; treatment decisions

ORIGINAL CONTRIBUTIONS

Early restorative intervention is especially inappro-priate because it starts a process known as the repeatrestoration cycle or the cycle of rerestorations, eachrestoration being less prophylactic and more iatrogenicthan the previous one,46 which can cause early loss of thetooth.45 Therefore, traditional restorative dentistry pro-tocols may be outdated.

In Norway, dentists changed the clinical criteria forintervention in the caries process.4,47 As a result, thenumber of restored surfaces was reduced dramatically inthe 1980s because of a change in the criteria for place-ment of restorations in the treatment of enamel lesions.47

The number of restored surfaces decreased by 92%because clinicians treated carious lesions in the enamelpreventively instead of restoratively.48 Those lesions wereapproximal. Lesions reaching into the outer one-half

presented are independent of suggested diagnosis.

TABLE 3

Influence of type of practice and years since graduation onrestorative threshold for approximal and occlusal carious lesions.RESTORATIVETHRESHOLD

TYPE OF PRACTICE,% (NO.)

P VALUE YEARS SINCEGRADUATION, % (NO.)*

PVALUE

GP† PediatricDentists

> 20 £ 20

Approximal Lesion‡

< .0001 < .0001

Grades 1 and 2 18.3 (291) 9.3 (10) 20.2 (213) 14.8 (111)

Grade 3 43.6 (694) 30.6 (33) 40.3 (426) 46.2 (347)

Grade 4 32.3 (515) 49.1 (53) 32.3 (341) 34.8 (261)

Grades 5 and 6 5.8 (92) 11.1 (12) 7.3 (77) 4.3 (32)

Occlusal Lesion§

Notsignificant .05

Grades 1 and 2 41.7 (660) 35.2 (37) 39.3 (409) 42.6 (317)

Grade 3 49.2 (778) 57.1 (60) 50.0 (521) 49.9 (372)

Grades 4 and 5 9.1 (144) 7.6 (8) 10.7 (112) 7.5 (56)

* At the time of the survey (2013).† GP: General practitioner.‡ Cross-tabulations related to approximal lesions: Restorative threshold per type of practice: 1,700 respondents.Restorative threshold per years since graduation: 1,808 respondents.

§ Cross-tabulations related to occlusal lesions: Restorative threshold per type of practice: 1,687 respondents. Restorativethreshold per years since graduation: 1,787 respondents.

of dentin weretreated successfully32% less often witha filling but ratherwith preventivemeasures.47

Dental educa-tion and treatmentcriteria have evol-ved over time.Younger dentistsmay be educatedabout new princi-ples such as mini-mal interventiondentistry, CariesManagement byRisk Assessment,and minimallyinvasive dentistry.This difference wasdemonstrated ina French study inwhich older den-tists favored open-

ing the whole fissure when restoring occlusal cariouslesions significantly more often than did youngerdentists.20

In our study, CA dentists with 20 or fewer years sincegraduation decided to restore approximal lesions inva-sively at a significantly later stage in caries progressionthan did those who graduated more than 20 years ago.Although in The Dental Practice-Based ResearchNetwork survey female dentists suggested a restorativetreatment of approximal carious lesions at a furtherprogressed stage than did male respondents,49 in ourstudy we did not find those sex differences. Results fromour study showed that pediatric dentists suggestedrestorative treatment for approximal carious lesions atsignificantly later stages than did GPs.

These groups have accepted that demineralized butnoncavitated enamel and dentin can be remineralized;therefore, the traditional operative approach of “drillingand filling” no longer may be necessary and appropriatefor such lesions. Noncavitated lesions have lost mineralat different degrees, but there is no physical loss ofenamel prisms, nor is there localized enamel break-down.50 The philosophy of minimal intervention dictatesthat operative intervention should be performed onlywhen cavitation is present.51 Some enamel lesions neverpenetrate into dentin, and up to 60% of lesions in theouter one-half of dentin are noncavitated and can bearrested.52,53 Therefore, postponement of restorativeintervention should be taken into considerationaccordingly.54,55

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TABLE 4

Restorative threshold for approximal lesions reported in various countries, withnumber of surveys sent out and percentage of respondents, lesion depth,preferred type of preparation, and preferred restorative material.AUTHOR, YEAR (COUNTRY) SURVEY POPULATION LESION DEPTH, %*

No. of SurveysSent

Response Rate,%

Outer One-HalfEnamel

Inner One-HalfEnamel

DEJ†

Riordan and Colleagues,26 1991 (Australia) 45 95.1 2 9 29

el-Mowafy and Lewis,28 1994 (Canada) 2,450 52.1 1 27 67§

Mejare and Colleagues,19 1999 (Sweden) 923 70.5 0 1 4

Tveit and Colleagues,18 1999 (Norway) 640 84.4 4** 15

Doméjean-Orliaguet and Colleagues,20

2004 (France)2,000 39.1 20 36 32

Traebert and Colleagues,27 2005 (Brazil) 840 89.4 32 23 25

Ghasemi and Colleagues,29 2008 (Iran) 1,033 †† 8 — 23

Baraba and Colleagues,23 2010 (Croatia) 800 38.0 10 32 39

Vidnes-Kopperud and Colleagues,4 2011(Norway)

3,654 61.0 1** 6

Heaven and Colleagues,25 2013 (UnitedStates)

901 63.0 2 42¶¶ 54

Khalaf and Colleagues,21 2014 (Kuwait) 200 92.5 2 8 7

Present Study (United States) 16,960 11.3 3 15 43

* Percentages are rounded for lesion depth, so they do not necessarily total 100.† DEJ: Dentinoenamel junction.‡ Not available.§ Just beyond DEJ.¶ Includes outer one-half of dentin.# Two different surveyed areas.** These studies only reported for the combined class and lesion depth.†† Dentists at 2 conferences.‡‡ Outer one-half of dentin.§§ Inner one-half of dentin.¶¶ The picture did not show the DEJ obviously.

ORIGINAL CONTRIBUTIONS

In a qualitative study of private practice dentists toassess barriers to the use of evidence-based clinical rec-ommendations in the treatment of noncavitated occlusalcarious lesions, the investigators realized that diagnosisof and knowledge about noncavitated lesions werelimited; despite the presented fact that the lesion wasnoncavitated, 50% would base their treatment decisionon the presence or absence of the sticking of a sharpexplorer.56 Future education of dentists should empha-size that noncavitated lesions can be remineralized easilybut that the surface of any noncavitated lesion can bechanged into a cavitated lesion by the stick of anexplorer.

For approximal lesions, in which the visibility of acavitation is limited, slight tooth separation by using awedge could be a last resort for clarification, resulting inmost correct clinical management decisions and mostcorrect decisions regarding the choice of treatment asshown by a study.57 Direct application of fluoride to thelesion or resin infiltration can be regarded as treatmentchoices.58-60

Results from some studies have shown that thetreatment prescription strongly depends on which caries

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risk scenario is given. When the risk is presented as high,more dentists recommend invasive treatment than whenthe risk is described as low for the same lesion depthconfined to enamel.25 The appropriate treatment sug-gestion still would have been a remineralization tech-nique and other caries management measures. In oursurvey, the caries risk was suggested as relatively low.Finally, determination of lesion activity by using, forinstance, the observational clinical criteria in Nyvad andcolleagues’ article61 also may influence the caries man-agement decision. As a shortcoming of this survey, inwhich participants were shown one photograph orradiograph to make a decision, no prior lesion status waspresented.

CONCLUSIONSThere is a wide disparity between CA dentists regardingtheir restorative treatment decisions. Most CA dentistsreported their restorative treatment threshold was forlesions that had reached the DEJ. Only one-third ofthe dentists would recommend a cavity preparationand restoration for a lesion extending into the outerone-third of dentin. In contrast, dentists in Scandinavia

TABLE 5

Restorative threshold for occlusal lesions reported in various countries, lesiondepth, suggested limit of preparation extension, and preferred restorativematerial.AUTHOR, YEAR(COUNTRY)

SURVEYPOPULATION

LESION DEPTH, %* PREPARATIONEXTENSION, %

RESTORATIVEMATERIAL, %

No. ofSurveysSent

ResponseRate, %

Grade1

Grade2

Grade3

Grade4

Grade5

Limited toCariousTissue

Extendedto WholeFissure

ToothColored

Amalgam Other

Mejare andColleagues,19

1999 (Sweden)

923 70.5 —† 6 67 27 — — — — — —

Doméjean-Orliaguet andColleagues,20

2004 (France)

2,000 39.1 2 47 47 3 — 61.2 36.0 79.9 17.1 3.0

Heaven andColleagues,25

2013 (UnitedStates)

901 63.0 1 9 34 33 2 — — — — —

Khalaf andColleagues,21

2014 (Kuwait)

200 92.5 — 4 28 43 24 78.9 21.1 88.7 9.7 1.6

Doméjean andColleagues,39

2015 (France)

2,000 41.9 2 37 55 6 — 67.8 30.0 92.6 7.3 0.1

Present Study(United States)

16,960 10.9 2 39 50 8 2 64.6 31.5 94.6 4.7 0.7

* Percentages are rounded for lesion depth.† Not available.

TABLE 4 (CONTINUED)

LESION DEPTH, %* PREPARATION TYPE, % RESTORATIVE MATERIAL, %

Outer One-ThirdDentin

Middle One-ThirdDentin

Inner One-ThirdDentin

TraditionalClass II

Tunnel Saucer ToothColored

Amalgam Others

40 11 9 —‡ — — — — —

5¶ — — 23.0/55.0# 77.0/45.0# — — — —

42 52 1 — — — — — —

62 19 1 28.3 47.4 24.3 81.5 15.5 3.0

11 1 — 12.0 33.3 54.7 76.1 20.5 3.4

18 3 — — — — — — —

58‡‡ — 11§§ — — — — — —

18 1‡‡ 0§§ 32.0 46.0 22.0 96.0 4.0 —

57 36 — 27.8 3.8 68.4 100 Banned —

3 1 — — — — — — —

40 19 24 49.2 24.9 25.9 88.6 11.4 —

33 4 2 54.1 23.5 22.4 92.6 6.4 1.0

ORIGINAL CONTRIBUTIONS

JADA -(-) http://jada.ada.org - 2016 9

ORIGINAL CONTRIBUTIONS

are much more reluctant to provide invasive restorativetreatment and prefer treatment at more pronouncedstages. The same is true for restorative treatment de-cisions for occlusal lesions, for which CA dentistsdecided to intervene restoratively at a dentinal lesionlevel at the outer or middle one-third of dentin.

Because clinical evidence shows that carious lesionscan be remineralized, early restorative treatment nolonger seems to be necessary or appropriate. Noninvasiveor minimally invasive measures should be taken intoconsideration when judging the need for invasiverestorative treatment. In this study, we found that recentdental graduates and pediatric dentists were more likelyto place their restorative threshold at deeper lesions forapproximal caries. These CA dentists seem to haveembraced a minimally invasive and, even more impor-tant, the remineralization concept.

However, dentists still need to be trained in dis-tinguishing between cavitated and noncavitated lesionsand when it is appropriate to use remineralizationtherapy rather than invasive restorative methods.Financial incentives for remineralization of noncavitatedlesions and more minimal invasive treatment would beappropriate to change behavior. n

Dr. Rechmann is a professor and the director, Clinical Sciences ResearchGroup, Department of Preventive and Restorative Dental Sciences, School ofDentistry, University of California, 707 Parnassus Ave., San Francisco,CA 94143, e-mail Peter.Rechmann@ucsf.edu. Address correspondence toDr. Rechmann.Dr. Doméjean is a professor, Department of Operative Dentistry and

Endodontics, School of Dentistry, University of Clermont-Ferrand,Clermont-Ferrand, France.Ms. Rechmann is a senior research associate, Department of Preventive

and Restorative Dental Sciences, School of Dentistry, University of Cali-fornia, San Francisco, CA.Dr. Kinsel is a health science associate clinical professor, Department of

Preventive and Restorative Dental Sciences, School of Dentistry, Universityof California, San Francisco, CA.Dr. Featherstone is a professor, Department of Preventive and Restorative

Dental Sciences, School of Dentistry, University of California, San Francisco,and the dean, School of Dentistry, University of California, San Francisco,CA.

Disclosure. None of the authors reported any disclosures.

The authors thank Drs. Espelid and Tveit for allowing the use of theiroriginal questionnaire and pictures for our Web-based survey.

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