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复合树脂的物理特性与汞合金不同,充填时需要改变传统的洞型设计。本文讨论了后牙Ⅱ类洞复合树脂充填的洞型设计原则。 (牙合)面洞形状和深度:(牙合)面洞型比汞合金修复洞型浅而窄。复合树脂有较高的抗张强度,挠曲强度,能密封边缘,但耐磨性低,聚合时发生收缩。其导热性能比汞合金低,需要减小洞底绝缘层厚度,不作预防性扩张。(牙合)面不断的磨损是复合树脂后牙充填的缺点,咬合接触点的磨损比非接触区大2.5倍,应该尽量减少(牙合)面尤其是边缘嵴部分的复合树脂修复。聚合时复合树脂体积收缩为1.5～2％,故洞型宜小,以减少边缘裂缝出现。
The physical properties of composite resin and amalgam different filling need to change the traditional hole design. This article discusses the design principle of cavity-type composite resin-filled cavities for posterior teeth. (Occlusal) surface hole shape and depth: (occlusal) surface hole than the amalgam repair shallow and narrow hole. Composite resin has high tensile strength, flexural strength, can seal the edge, but the wear resistance is low, shrinkage occurs during polymerization. Its thermal conductivity than the amalgam low need to reduce the thickness of the insulating layer at the bottom of the hole, without preventive expansion. (Occlusal) surface wear is the shortcomings of compound resin posterior teeth filling, occlusal contact wear than non-contact area 2.5 times larger, should minimize (occlusal) surface, especially the edge of the ridge part of the composite resin repair. The volume shrinkage of the composite resin during polymerization is 1.5-2%, so the hole type should be small so as to reduce the occurrence of edge cracks.