Clinical evaluation of restoring residual root and crown with crown lengthening surgery

Objective To evaluate the clinical effect of the crown lengthening surgery on the restoration of residual root and crown with subgingivally involved defect. Methods From May 2004 to June 2005, according to the subgingival depth of the defect. 36 teeth from 32 patients with subgingivally involved defect were diveded into two groups: group A(20 teeth, depth3.0mm), group B (16 teeth, 3.0mm ≤depth≤4.0mm). All teeth were treated by the crown lengthening first and then underwent post-crown prosthesis at 6 weeks postoperatively. After fowllowing up for 6 months the preoperative and postoperative date were reviewed and analyzed. Results The teeth sections of two groups were exposed well and the color of the gingival margin of two group looked normal. The overall effective rate was 100% and satiafying rate was 77.78%. The restoration of group A without any teeth loose was better than that of group B with 50.00% teeth loose at degree Ⅰ. Postoperative PD, PLI and SBI were better than those preoperatively (P0.05). There were no differences on the periodontal index among the two groups (P0.05). Conclusion Crown lenthening surgery is a good method for the protection and restoration of residual root and crown, but should be limited to the right patients.