Restorative Dentistry

The effect of finishing and poiishing on the decisionto repiace existing amaigam restorationsMariane Cardoso, DDSVLuiz N, Baratieri, DDS, MS, PhD*VAndré V, Ritter, DDS""

Objective: The purpose of this investigation ivas to evaluate the influence of finishing and polishing proce-dures on the decision to replace existing amalgam restorations. Method and materials: Twenty Ciass Iand Class il amalgam restorations, free from obvious defects, were selected in 6 patients The restorationswere photographed before and after being submitted to a standard finishing and poiishing procedure, inthe first phase, the preoperative siides were examined by 27 dinicians and senior dentai students, whowere instructed to inspect each restoration and answer a questionnaire indicating if and why the restorationneeded to be repiaced. Two weeks iater. the postoperative slides were presented to the same examiners,who were asked to answer the same questionnaire as before. Results: At the first phase, there were 236decisions (44%) to repiace existing amaigam restorations. Foiiowing the finishing and poiishing procedures,114 decisions (21%) were made to repiace existing amalgam restorations. This difference was statisticaiiysignificant. Secondary caries was the most common reason for repiacement. Conclusion: The finishingand poiishing procedure reversed the decision to repiace old amalgam restorations. (Quintessence Int1999:30:413-418)

Key words: amalgam, clinical criteria, decision-making process

CLINICAL RELEVANCE: A simple finishing and polish-ing procedure may inffuenoe the decision to replace aquestionable amalgam restoration.

Dental amalgam bas been used as a direct restora-tive material since tbe end of tbe last century.'

Regardless of tbe increasing use of resin compositerestorative materials, dental amalgam is still the mostwidely used dental material for tbe restoration of pos-terior teetb,̂

Tbe longevity of amalgam restorations varies, de-pending on the size of tbe cavity preparation (widtb ofisthmus), tbe alloy used, and tbe tootb in question,among otber factors. On average, amalgam restora-tions last 6 to 11 years,''-''

• Private Practice, Florianópoiís, Santa Catalina, Biazil,

"Professor and Chair, Department of Operatiue Dentislrv, Federal Uni-versity af Santa Catarina, Florianópoiís, Santa Catarina, Brazil

'"Alixrliaiy Professor, Department ot Operative Derlistry, Federal Univer-sily of Santa Catarina, Florianópolis, Santa Catarina, Brazil; Resident,Department of Operative Dentistry and Denial Researcti Center, Uni-versity ol North Carolina at Chapel Hill, School of Dentistry, Chapel Hill,North Carolina.

fleprint requests: Dr André V, Ritter, Department of Operative Dentistry,Uniuersity ol North Carolina at Chapel Hill, School of Dentistry, CB# 7450,Chapel Hill, North Carolina 27599-7450. E-mail: iHÏPERLINK maitto;cientist@ccs, Jfsc.br Andre_Rifteredentistryunc,eöu

Amalgam restorations may fail and require replace-ment because of secondary or recurrent caries, bodyfracture, marginal fractures, poor anatomic form, and,to a lesser degree, overhangs,^'-'' However, tbe deci-sion to maintain, repair, or replace an existing amal-gam restoration is far from a logical process."'" Tbecriteria used to make this decision are generally per-sonal and empirical." Significant variations in treat-ment decisions are observed not only among differentclinicians but also from tbe same person at different

In general, diagnosis of caries on restored teeth istnore complex than on unrestored teetb."'^ Despitethis complexity, a dentist spends a considerableamount of his or ber clinical time replacing restora-tions tbat be or she judges to be unacceptable,'^-'*Also, it bas been sbown tbat, many times, tbe newrestoration presents tbe same problems as the oldone.'"'^ In a recent in vitro study, Oleinisky et al'^sbowed tbat the criteria used by students and clini-cians to make a treatment decision regarding oldamalgam restorations are imprecise, Tbese authorsshowed tbat tbe restoration's appearance, wbicb canbe improved witb refinishing and repolisbing proce-dures, significantly affected tbat decision, Tbis conclu-sion was reacbed witb tbe observation tbat most deci-sions to replace amalgam restorations were reversedafter tbese restorations had been submitted to a stan-dard finisbing and polishing procedure.

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Fig la Occlusal view ol an amaigam restoration before bei,ngsubmitted to a standard finisining and polistiing procedure.Ciinical slides corresponding to this image, as well as all theothers, were examined with x20 magnification in the reviews.

Fig 1b Occlusal view of the same tooth shown in Fig la, afterthe finishing and polishing procedure.

Fig 2a Occlusal view of an amalgam restoration belore being Fig 2b Occiusal view ot the same tooth shown in Fig 2a, aftersubmitted to a standard finishing and polishing procedure the finishing and poiishing procedure.

Fig 3a Ocolusal view of amalgam restorations before being sub-mitted to a standard finishing and poiishing procedure.

Fig 3b Occiusai view of the same tooth shown in Fig 3a. afterthe finishing and polishing procedure

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The purpose of this study was to investigate tbeeffect of refinishing and repolishing procedures on thedecision to replace existing amalgam restorations.Also, tbe reasons for the replacement decisions wereassessed. The null hypothesis tested in this study wasthat the finishing and polishing procedure does not in-fluence the decision to maintain, repair, or replace oldamalgam restorations.

METHOD AND MATERIALS

Twenty amalgam restorations present in 6 patients reg-ularly attending the Operative Dentistry Clinics at theFederal University of Santa Catarina (Fiorianópolis,Santa Catarina, Brazil) were selected for the study. TheUniversity Ethics Committee approved the study, andthe patients were informed about its objectives, meth-ods, benefits, and risks. Only patients with good oraicare and general health were included in the study.

The restorations selected exhibited no evident fail-ure. Also, only restorations with established inter-proximal contacts were selected. Tbe type of alloyemployed and the age of tbe restorations were un-iinown factors.

Bitewing radiographs were obtained for eachrestoration before tbe initiation of the study, and infor-mation regarding the patient's diet, bygiene, and use offluoridated toothpaste was recorded in a patient cbart.This information provided some insight regarding tbecaries risk of the patient, which may influence tbetreatment decision.

High-quality slides (occiusai view at 2:1 magnifica-tion) of each restoration were obtained before (Figsla, 2a, and 3a) and after (Figs lb, 2b, and 3b) a stan-dardized finisbing and polisbing procedure. The fin-ishing and polishing procedure was performed usingrotary instruments at slow speed and polishing pastesunder rubber dam isoiation.

The preoperative and postoperative sets of slideswere inspected by 3 groups of examiners (Table 1), witba 2-week interval between tbe reviews. Group 1 con-sisted of senior dental students from tbe FederalUniversity of Santa Catarina, Schooi of Dentistry.Groups 2 and 3 consisted of ciinicians with 5 to 10years of practice, and 15 to 20 years of practice, respec-tively. At tbe first review, tbe examiners inspected onlythe preoperative slides; they were not aware of the sec-ond stage of the study or of its objectives and method-ology. At tbe second review, tbe examiners inspectedthe postoperative slides. Tbe slides were mounted in amagnification device (Ampligrapb, Fiorianópoiis, SC,Brazil) that provided x20 magnification.

The examiners completed tbe following question-naire:

TABLE 1

Group123

Distribution of the examiners' groups

Category

Senior studentsCliniciansClinicians

Years ot practice0

5-1015-30

n

999

TABLE 2 Distribution of the examiners' answersfor the first question (decision to replace) beforeand after the finishing and polishing procedure

Gro j p 1 • Group 2- Group 3'Before After Before After Before After

YesNo

27%73%

9%91%

47%53%

28%72%

57%43%

43%57%

•Significance levels'group 1:x== 1B.99, P< 0.001; gioup 2i ;(= = 13.74,P = 0.002;grOLp3ï' = 7 51, P= 0.006.

1. Question 1 (decision to repiaee): In your opinion,docs this restoration call for repiacement?YesNo

2. Question 2 (reason for replacement): If youranswer for question 1 was "yes," for which reason?A. Seeondary cariesB. Body fractureC. Deficient anatomic form (sculpture/contour)D. Ditched marginE. Marginal overhangsF Otber

The same questionnaire was used before and aftertbe finishing and polisbing procedure. The patient'sanamneses information and the radiographs wereavaiiable, if requested.

Results were tabulated and submitted to statisticalanalysis. Cbi-square {-/_-) and kappa tests were per-formed, because tbese are measurement units on anominal level.

RESULTS

Table 2 shows the distribution for tbe answers of tbedifferent groups to the first question (decision toreplace) before and after tbe finishing and pohsbingprocedure (first and second reviews). Ali groups ex-hibited a statisticaily significant reduction in the deci-sion to replace after the experimental procedure.Table 3 sbows tbe distribution for tbe answers to thesecond question (reason to replace). Secondary caries

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TABLE 3 Distribution of the examiners' answersfor the second question (reason to replace) beforeand after the finishing and polishing procedure

Group 1 Group 2 Group 3Betöre Atter Before After Betöre After

SecondarycariesBodyfractureDitohedmarginPooranatomyOverhangsOther

49

51%

15%

12%

14%0%

0%

16%

10%0%0%

83

57%

6%

16%2%1%

52

48%

8%

13%

31%0%0%

17%

24%9%1%

4%

55%•%0%

"Total number oí answers lor thai particular variable.

TABLE 4 Use Of radiographs and anamnesesinformation (n = 27 examiners)

Group123

Total

Preoperative radiographsBefore15%1 1 %

1 %27%

After22%1 1 %4 %

37%

Anamneses informationBefore

4%0%4%8%

After4%0%4%8%

was the most common answer to the seeond ques-tion, both before and after the finishing and polishingprocedure.

Table 4 shows the frequency of requests for addi-tional information, ie, the anamneses chart and/orradiographs. Fewer than 40% of the examiners askedfor the radiographs, and 8% asked for the anamnesescharts.

DISCUSSION

It is well known that the restorative dentist spendsmost of his or her clinical time replacing old, "failed"restorations.'^-" However, it has also been shown thatthe decision-making process regarding restorationreplacement is subjective and not based on clearcriteria.'"

There is no clear protocol that defines preciselywhen a restoration should he replaced. However, thisdecision is made several times every day by cliniciansall over the world, in many cases with no scientificevidence.''-^^ This investigation showed that the crite-ria used to decide the appropriateness of replacingamalgam restorations are poorly defined among thegroups of examiners participating in tiiis study. Thistendency is probably not confined to the loeationexamined (Florianópolis, Santa Catarina, Brazil),because many other authors have presented similarresults at other sites using different methods.'̂ •'̂ •̂ •̂'•'

In this study, the influence of the finishing and pol-ishing procedure on the decision to replace amalgamrestorations is clearly demonstrated, because this pro-cedure significantly reduced the numher of decisions

for replacement in all groups (P = 0.0504), These re-sults are in accordance with the in vitro resuits re-ported by Oleinisky et al."

The main reason for amalgam replacement wassecondary caries, which is in accordance with thefindings reported by Mjör,' All 3 groups of examinersdecided to replace fewer restorations because of sec-ondary caries after the finishing and polishing proce-dure. In group 1, this reduction was 44̂ /0, in group 2it was 47%, and in group 3 it was 34%. One factorthat may have contributed to the change in the treat-ment decision is the difficulty in diagnosing sec-ondary caries.'-'"-'-^' This factor is responsible formany false-positive diagnoses, and preventive actionsshould be implemented to minimize the subjectivenature of situations in which secondary caries is anissue.

Secondary caries should be approached the sameway as primary caries; ie, it is not the restoration otthe defect that will cure the disease. Basic preventivemethods, such as diet control, fluoride use, and oralhygiene by the patient, should be considered in thetreatment plan to achieve low levels of primary andsecondary caries.^"^

Regarding ditched margins, all 3 groups changedtheir decisions after the finishing and polishing proce-dure. The larger variation was observed in group 3,with a reduction of 82%. However, this result does notindicate that the other groups did not notice theditched margins but rather that they did not considerthem a reason to replace the restorations.

Poor marginal integrity seems to be a frequentreason to replace restorations, although Barbakow elaP' have shown that 100% of amalgam restoration

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Cardoso et al •

margins are defective 6 months after they are placed.Poor marginal integrity, therefore, should not justifythe replaeement of a restoration. Either periodic recallto monitor the restoration and the patient's caries riskor the repair of the margin is preferable to totalreplaeement.-*

The marginal defects that appear in the tooth-restoration interface are simiiar to pit and fissuredefects hecause they act as plaque accumulationsites,'-^ Therefore, if it is possible to maintain occiusaipits and fissures free of caries, it should also bepossible to do the same with the marginai defects inold restorations. Plaque control is as caries preventivein occlusal pits as it is in ditched margins, providedthat these margins are accessible for cieaning.

Many of the marginal defects diagnosed as sec-ondary caries could be treated conservatively with asimple finishing and polishing procedure because realsecondary caries is rare on occlusal areas.̂ ^ improve-ments in plaque control, diet, and the correct use offluoride are additional preventive actions that shouldbe implemented to avoid the unnecessary replacementof restorations.̂ ^

In this study, the examiners mentioned that the factthat they could not use an explorer for the reviewswas a problem because the observations were onlyvisual. However, the use of an explorer to diagnosecaries is a controversial issue.'•'•'='̂ ' Probing has shownto be unreliable for diagnosis of caries in fissures andditched margins.'^""

Another frequently cited reason for replacing therestorations in this study was poor anatomic contour.Poorly contotired restorations can lead to periodontal.occlusal, and restorative probletns.-' However, to solvethese problems, restorations do not aiways need to bereplaced," unless they are badly compromised by theircontour, which was not the case in this study.

The use of bitewing radiographs is important in thediagnosis of primary and secondary caries," especiallyin Class II restorations because the cervical area is fre-quently affected by recurrent caries.'' Espelid artdTveit'-» have shown that clinical examinations, supple-tnented by radiographie images, lead to increased sen-sitivity in the diagnosis of secondary caries, Jokstad etal" showed that the patient's age and caries risk areimportant factors among the restoration replaeementcriteria, Kidd '̂ also reported that information on diet,hygiene, and fluoride use are important to plan thepreventive and restorative treatment. However, veryfew examiners requested such information in the pre-sent study-

When an old restoration is removed, additionaltooth structure is removed as well because of theaction of the bur.̂ This weakens the tooth structure,and, therefore, it is likely that a more eomplex restora-

tion will be needed in the future." This approachtends to diminish the prognosis of the tooth, as a con-sequence of the repetitive restorative cycle," It hasbeen shown repeatedly that restorations do not curedental caries.''^^^ Also, a large number of the prob-lems in old amalgams are not solved by restoration re-placement, Ciinieians tend to believe that, "when indoubt, restore," which shows good faith in their owntreatments. The fact that they spend more than SO"™ oftheir clinieal time replacing their own restorations andthose of their colleagues demonstrates clearly that thisis not a good practice.'^-'« The appropriate ciinicaiconduct should be "when in doubt, wait, obser\'e, con-troi, and, if necessary, repair or repiace." The dentistshould always take into consideration and respect thepatient's needs and move toward a more health-oriented approach.

There is an additional point that should beaddressed regarding the results presented in this inves-tigation. The fact that finishing and polishing proce-dures were able to reduce the number of decisions torepiace some restorations, ie, some restorations con-sidered compromised at the first examination wereconsidered not compromised in the second review,can be interpreted in 2 different ways. First, it canbe theorized that the first decision was wrong (false-positive), and the finishing and polishing procedureprevented an unnecessary replacement. However, itcan also be inferred that the first decision was correct,a situation in which the finishing and polishing proce-dure couid have masked an existing problem, leadingto a false-negative decision; this would mcrciy havepostponed necessary repair or replacement of theexisting restoration.

The finishing and polishing approach proposed inthis study is best suited when the clinician has controlof the patient records, mainiy radiographs and assess-ment of caries risk. Also, appropriate recalls should bescheduled to control for any false-negative decisions.All the restorations examined in the present study arein a recali program; the long-term effects of the pro-posed approach will he presented in the future.

CONCLUSION

1. The finishing and polishing procedure strongly in-fluenced the decision to replace or maintain existingamalgam restorations {significance level: y^ — 7.51;P= 0.0504).

2. Radiographs are not used routinely to make thedecision whether or not to replace an old amalgamrestoration. Also, information about diet, oraL,hygiene, and fluoride use is seldom used as a diag-nostic adjunct.

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ACKNOWLEDGMENTS

The authors would like lo express their gratitude to Sergio Freitas,DDS, Assistant Professor, Fédérai University of Santa Caiarina,Brazii, for his help with lhe slatisticai analysis and to Sandra L,Myers, DDS, Assistant Professor, University of Minnesota, for herhelp in editing this manuscript.

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