洞形与抗剪切能力的关系

Relationship between the shaqe of the cavity and bond strength of the dentin

目的研究盒型洞两侧的余留牙体组织与底面不同移行方式时抗剪切能力的关系。方法将新鲜离体牙的一部分制备成符合要求的两组试件。第一组试件的两侧壁轴向加载,第二组试件两侧壁侧向加载,分别记录两侧不同形状侧壁的抗剪切力值。结果轴向加载,不同形状的侧壁抗剪切力无显著性差异(P>0.5);侧向加载,不同形状的侧壁抗剪切力有高度显著性差异(P<0.00001)。结论两侧壁受到轴向负载时,其抗剪切能力与洞形无关,受侧向负载时,其抗剪切能力与洞形有密切关系。

AIM：To evaluate the relationship between the shape of cavity and bond strength of the dentin. METHODS： Forty freshly extracted molars were ground flat to expose the dentin and randomly divided into two groups. The specimens were subjected to the tensile and shear bond tests. RESULTS： There were no significant differences of tensile bond strength of the dentin for the first group （P 〉0.5）. On the other hand, there were significant differences of shear bond strengths of the dentin for the second group （P 〈 0. 00001 ）. CONCLUSION： The shape of the cavity had a greater influence on the shear bond strength of the dentin than the tensile bond strength of the dentin.