Grey discolouration and marginal fracture for the diagnosis of secondary caries in molars with occlusal amalgam restorations: an in vitro study.
Grey discolouration of the enamel around a filling and marginal fracture are often reasons to replace restorations due to suspicion of secondary caries. The aim of this study was to establish the validity of grey discolouration and marginal fracture for the diagnosis of caries at the enamel-dentine junction (EDJ) next to an amalgam filling. The occlusal surfaces of 161 extracted molars with occlusal amalgam fillings were photographed on colour slides, from which grey discolourations and marginal fracture were recorded. The size of the fracture was scored using a modified Mahler scale with six categories: score 1 = no marginal fracture (< 30 microns), score 6 = fracture width > 200 microns. Secondary caries at the EDJ was scored on radiographs of 700 micron sections of the molars. Both radiolucencies and radiopacities in dentine were scored as caries. The sensitivity of grey discolouration for detection of secondary caries was 50% and the specificity 91%. The positive and negative predictive values were 71 and 80%, respectively. Marginal fracture was evaluated at five different levels of severity. Although there was caries present more frequently at the EDJ under severely fractured margins, marginal fracture was found of little diagnostic value at all levels. Only marginal fracture at threshold level V provided a positive predictive value (50%), which was significantly higher than the caries prevalence (31%). It is concluded that width of marginal fracture, as defined by the Mahler scale, has hardly any value for the diagnosis of secondary caries. However, grey discolouration may be a useful diagnostic aid.
Department of Cariology and Endodontology, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands.
M P
MP
Rudolphy
J P
JP
van Amerongen
C
C
Penning
J M
JM
ten Cate
D003116:Color; D003723:Dental Amalgam / Q000009:adverse effects*; D003731:Dental Caries / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D003743:Dental Enamel / Q000000981:diagnostic imaging / Q000473:pathology; D003793:Dental Restoration, Permanent / Q000009:adverse effects*; D003804:Dentin / Q000000981:diagnostic imaging / Q000473:pathology; D004868:Equipment Failure; D006801:Humans; D008963:Molar / Q000000981:diagnostic imaging / Q000473:pathology; D010781:Photography; D011237:Predictive Value of Tests; D015995:Prevalence; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013499:Surface Properties; D014075:Tooth Discoloration / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology
D003723:Dental Amalgam