Comparison of the two methods of prosthodontics in subgingival residual root of premolar

Objective To compare the efficacy of simple porcelain fused to metal crown with combined crown in restoration of subgingival residual root of premolar.Methods 128 cases of subgingival residual root of premolar due to fracture or secondary caries were randomly divided into two groups(A and B).After having been conducted with endodontic therapy and restored with prepared metal screw post and resin core ,the group of A was restored with simple porcelain fused to metal crown,the group of B was restored with combined crown.Results There is significant difference between tow groups after the observation of two years.The success rate of B is higher than A group. Conclusion Combined porcelain fused to metal crown to the subgingival root of the premolar is more effective than simple crown.