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]

參考譯文

更換牙體充填物占所有臨床操作的75%，充填物邊緣的齲壞(繼發(fā)齲)是牙科醫(yī)生更換充填物的常見原因。繼發(fā)齲根據(jù)組織學研究可分為兩類：鄰近充填物的牙齒表面外層損壞；推測可能由充填物與牙齒之間的滲漏造成的壁損。鄰近牙色充填物的外層損害可能相對容易診斷，但是璧損的臨床證據(jù)還不清楚。需手術治療的活動性繼發(fā)齲的區(qū)域可能會有嚴重的微生物感染。因此合理研究這些診斷難點的方法就是研究充填物的顏色變化和邊緣溝與充填物移除后牙本質的感染程度的關系，這樣才能明確這些標準的可靠性。含鄰近充填物的直接齲洞組可作為有效對照,因為這些病例的臨床診斷很少有爭議。

因此本次研究中，我們研究了牙色充填物邊緣的染色線、充填物邊緣可以完整透過釉質的變色牙本質、和(或)可能引起充填物下方牙釉質-本質交界處感染牙本質的溝槽。此外，我們從充填物邊緣采集菌斑，以確定在牙齒表面或充填物界面的牙菌斑中細菌的組成數(shù)目和比例是否與任何深層病變的活動相關。

                                                                                           (翻譯:賴光云，審校:孫恒贅)

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