RESUMO
Objective To compare the applicatied effect of two kinds of post core porcelain fused to metal crown for restoration of residual crown of first molar .Methods 52 patients with residual crowns of first molars (98 teeth) were selected.According to the random numerical table method ,they were divided into group A[post core crown of metal casting in 27 cases ( 49 teeth ) ] and group B [ post core crown of screw thread amalgam in 25 cases (49 teeth)].After a year of follow -up,the success rate of the two groups was compared .Results Metal casting core crown pile was broken at 0 in group A and at 3 in group B,the success rate of group A was 93.88％,and the success rate of group B was 79.59％,the difference was statistically significant between the two groups (χ2 =4.346, P<0.05).Conclusion The retention,resistance and durability of post core crown of metal casting is far superior to post core crown of screw thread amalgam ,and it is a more ideal repair method .