The replacement of dental restorations accounts for some 75% of all operative work, and caries at the margins of restorations (secondary caries) is frequently a reason given by dentists for replacing restorations (Kidd et al. , 1992). Histological studies (Hals and Kvinnsland, 1974) describe the secondary caries lesion in two parts: an outer lesion formed on the surface of the tooth next to the filling and a wall lesion which is assumed to develop if there is leakage between the restoration and the tooth. While an outer lesion next to a tooth-colored restoration may be relatively casy to diagnose, the clinical manifestations of the wall lesion are not known. In particular. the relevance of a line of stain around a tooth-colored filling and discoloration of the dentin shining up through intact enamel adjacent to the restoration are difficult to interpret. Do these appearances indicate leakage, residual stain left when the restoration was originally inserted, or new,

active secondary caries in need of operative as well as preventive treatment? In addition, the clinical relevance of a macroscopic ditch in between a tooth-colored filling and the tooth is unknown, although both marginal staining and ditching have been shown to cause dentists to replace toothcolored restorations (Qvist et al. , 1990). It seems reasonable to suggest that areas of active secondary caries in need of operative intervention will be heavily infected with micro-organisms. A logical way to investigate these diagnostic difficulties may therefore be to investigate associations between color changes and marginal ditches noted with a restoration in place and the degree of infection of the dentin once the same restoration is removed, so that the reliability of these criteria can be determined. The inclusion of a group consisting of frank carious cavities next to the filling margin can serve as a useful control, since in these cases the clinical diagnosis is rarely in dispute.

In the present study, we have therefore investigated whether a line of stain at the margin of a tooth-colored restoration, discoloration of dentin shining up through intact enamel at the margin of the filling, and/or ditching predicted the presence of infected dentin below the restoration at the enamel-dentin junction. In addition, we sampled plaque from the margins of restorations to determine whether the number and percentage bacterial composition of the plaque at the

tooth surface/restoration interface were associated with the activity of any lesion beneath.

                                                                  [J Dent Res,1996;75(12):1942-1946]

参考译文

更换牙体充填物占所有临床操作的75%，充填物边缘的龋坏(继发龋)是牙科医生更换充填物的常见原因。继发龋根据组织学研究可分为两类：邻近充填物的牙齿表面外层损坏；推测可能由充填物与牙齿之间的渗漏造成的壁损。邻近牙色充填物的外层损害可能相对容易诊断，但是璧损的临床证据还不清楚。需手术治疗的活动性继发龋的区域可能会有严重的微生物感染。因此合理研究这些诊断难点的方法就是研究充填物的颜色变化和边缘沟与充填物移除后牙本质的感染程度的关系，这样才能明确这些标准的可靠性。含邻近充填物的直接龋洞组可作为有效对照,因为这些病例的临床诊断很少有争议。

因此本次研究中，我们研究了牙色充填物边缘的染色线、充填物边缘可以完整透过釉质的变色牙本质、和(或)可能引起充填物下方牙釉质-本质交界处感染牙本质的沟槽。此外，我们从充填物边缘采集菌斑，以确定在牙齿表面或充填物界面的牙菌斑中细菌的组成数目和比例是否与任何深层病变的活动相关。

                                                                                           (翻译:赖光云，审校:孙恒赘)

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