Abstract: PURPOSE: To evaluate the clinical effects of restoring the subgingival residual crowns of anterior teeth with periodontal and prosthodontics treatment. METHODS: Twenty-five patients with 28 subgingival residual crowns were treated by root canal therapy, crown lengthening surgery, and restored with post- core crown after 8 weeks. Changes in tooth mobility, gingival health were examined and clinical effect of crown restoration were evaluated at regular intervals of 1 month, 6 months and 12 months after restoration respectively. RESULTS: One year after restoration,the gingival health was improved and the overall effective rate was 89.28%. Three teeth were failed, one was due to mild tooth loose,and the other two were due to exposure of crown margin. CONCLUSIONS: For subgingival residual crowns of anterior teeth, crown lengthening surgery can conserve the biological width, and produce enough height of ferrule. Restoration can obtain satisfactory effects, but the indication must be selected properly.

Key words: Crown lengthening surgery, Ferrule, Post-core crown, Subgingival residual crowns of anterior teeth