Effects of PFM Margin Designs on Gingival

Objective To study the effects of differently location of crown margin on the health of periodontium. Methods Under circumstances of strictly limiting crown contour,margin discrepancy and periodontal conditions of porcelain-fused-to-metal crown,a total of 22 mandibular PMF of 22 volunteers were randomly divided into two groups:subgingival and gingival crest. At the point of 4 weeks and 8 weeks after operation,gingival cervical fluid (GCF)were collected and weighed,and the levels of aspartate aminotransferase(AST)and alkaline phosphatase(ALP) of GCF were tested. Results After cementation of PMF,both amount of GCF and level of AST and ALP increased significantly,while the effects of two groups(subgingival and gingival crest ) on periodontium show no statistically significant change. Conclusions Crown margin is unfavourable to periodontium health,while the effects of differently location of crown margin on the health of periodontium are no statistically significant.