Holtan J R, Nystrom G P, Douglas W H, Phelps R A
Quintessence Int. 1990 Feb;21(2):117-22.
Glass-ionomer cements, with their ability to bond to dentin, have been reported to produce less microleakage than several other restorative resin materials. This matched-pair study reports the effect on microleakage of placement of a light-curing glass-ionomer cement used as a liner when extended out to the dentinal cervical cavosurface margin or held short of that margin. Pairs of circular Class V cavities involving 50% enamel, with bevel, and 50% cementum were cut in 31 extracted third molars. After placement of the glass-ionomer cement, etching of the bevel, and placement of a resin bonding system, microfilled resin was placed over the bonding agent in one increment, light-cured, finished, and given 500 thermocycled 500 times between 5 and 55 degrees C. A silver nitrate staining technique was used to evaluate microleakage measured in graticular units (gu) along the dentinal interface under stereomicroscopy. The extension of the glass-ionomer liner out to the dentinal cavosurface margin did not significantly improve microleakage performance compared to performance of the liner when it was placed short of that margin and covered by a resin veneer. From other considerations, such as the potential for mechanical breakdown of the glass-ionomer cement when exposed to the oral environment and abrasion, and the possibility for improved esthetics, the clinician should consider holding the glass-ionomer liner short of the dentinal cavosurface margin and covering it with a composite resin veneer of a thickness consistent with structural integrity.
玻璃离子水门汀因其与牙本质的粘结能力，据报道与其他几种修复性树脂材料相比，产生的微渗漏较少。这项配对研究报告了用作衬层的光固化玻璃离子水门汀延伸至牙本质颈洞缘或短于该边缘时对微渗漏的影响。在31颗拔除的第三磨牙上制备了成对的圆形V类洞，其中50%为有斜面的釉质，50%为牙骨质。放置玻璃离子水门汀、蚀刻斜面并放置树脂粘结系统后，将微填料树脂一次性覆盖在粘结剂上，光固化、修整，并在5至55摄氏度之间进行500次热循环。采用硝酸银染色技术在立体显微镜下评估沿牙本质界面以网格单位（gu）测量的微渗漏情况。与玻璃离子衬层短于牙本质洞缘并被树脂贴面覆盖时相比，将玻璃离子衬层延伸至牙本质洞缘并不能显著改善微渗漏性能。从其他方面考虑，如玻璃离子水门汀暴露于口腔环境时机械破坏的可能性和磨损，以及美学改善的可能性，临床医生应考虑将玻璃离子衬层短于牙本质洞缘，并使用厚度与结构完整性一致的复合树脂贴面覆盖它。
