Rudolphy M P, van Amerongen J P, Penning C, ten Cate J M
Department of Cariology and Endodontology, Academic Centre for Dentistry Amsterdam (ACTA), The Netherlands.
Caries Res. 1995;29(5):371-6. doi: 10.1159/000262095.
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.
补牙周围牙釉质的灰色变色以及边缘折裂常常是因怀疑继发龋而更换修复体的原因。本研究的目的是确定在银汞合金补牙旁牙釉质 - 牙本质界（EDJ）处，灰色变色和边缘折裂用于诊断龋病的有效性。对161颗有咬合面银汞合金补牙的拔除磨牙的咬合面拍摄彩色幻灯片，记录其中的灰色变色和边缘折裂情况。使用改良的马勒量表对折裂大小进行评分，分为六个类别：评分1 = 无边缘折裂（<30微米），评分6 = 折裂宽度>200微米。在磨牙700微米切片的X光片上对EDJ处的继发龋进行评分。牙本质中的透射区和阻射区均计为龋。灰色变色检测继发龋的敏感性为50%，特异性为91%。阳性预测值和阴性预测值分别为71%和80%。对边缘折裂在五个不同严重程度水平进行评估。尽管在严重折裂边缘下方的EDJ处龋病更常见，但发现边缘折裂在所有水平的诊断价值都不大。只有阈值水平V的边缘折裂提供了阳性预测值（50%），显著高于龋病患病率（31%）。结论是，按照马勒量表定义的边缘折裂宽度对继发龋的诊断几乎没有价值。然而，灰色变色可能是一种有用的诊断辅助手段。
