Tuntiprawon M, Wilson P R
School of Dental Science, University of Melbourne.
Aust Dent J. 1995 Feb;40(1):17-21. doi: 10.1111/j.1834-7819.1995.tb05607.x.
The effect of increasing cement thickness on the fracture strength of aluminous porcelain jacket crowns was investigated in this study. Thirty-three aluminous porcelain jacket crowns were divided into three groups. In Group 1, only platinum foil was used to provide cement space. In Group 2 two layers and Group 3 four layers of die spacer were painted onto the metal die before impression taking. Each crown was cemented onto a metal die with zinc phosphate cement and loaded until fracture. The maximum force to break each crown was recorded. The average fracture load was 408 N for Group 1,365 N for Group 2 and 324 N for Group 3. ANOVA (SPSS) found a significant difference (p < 0.05) between groups. A Scheffe Test revealed a significant difference between Groups 1 and 3. It was concluded that increasing the cement thickness above 70 microns reduced the fracture strength of porcelain jacket crowns.
本研究调查了增加粘结剂厚度对铝瓷全冠断裂强度的影响。33个铝瓷全冠被分为三组。第1组仅使用铂箔来提供粘结剂空间。第2组在取印模前在金属代型上涂两层代型间隙涂料，第3组涂四层。每个全冠用磷酸锌粘固剂粘固到金属代型上并加载直至断裂。记录每个全冠断裂时的最大力。第1组的平均断裂载荷为408 N，第2组为365 N，第3组为324 N。方差分析（SPSS）发现组间存在显著差异（p<0.05）。Scheffe检验显示第1组和第3组之间存在显著差异。得出的结论是，将粘结剂厚度增加到70微米以上会降低瓷全冠的断裂强度。
