Effects of Change of Crown Contour on Health of Gingival

Objective To study the effects of differently increasing crown contours on the health of periodontium.Methods A total of 72 mandibular teeth of 12 volunteers were randomly divided into three groups,each group consisting of 21 teeth.The buccal surfaces of the teeth were excessively contoured 0.2mm,0.4mm and 0.8mm respectively.At the point of preoperation and the point of 1 week,4 weeks and 8 weeks after operation,gingival cervical fluid (GCF)were collected and weighed.Also the levels of alkaline phosphatase(ALP) and aspartate aminotransferase(AST) of GCF were tested.Results The most amount of GCF and highest level of ALP and AST, were presented in the 0.8mm than both in the 0.4mm and in the 0.2mm.The 0.4mm group was the second.However in the 0.2mm group,all indexes showed no statistically significant change.Conclusions Excessive crown contour is unfavourable to periodontium health.The more excessively contoured,the more damaged to the periodontium.