The clinical study on single crown and combined crown applied to the restoration for residual roots of premolar

Objective To compare the clinical effect between single post-core-crown and combined crown applied tot he restoration for residual roots of premolar.Methods A total of 203 cases were randomly divided into two groups according to two different treatments.Among 238 teeth with residual roots of premolar,116 teeth were restored with singlep orcelain fused to metal crown and 122 teeth were restored with combined porcelain fused to metal crown.ResultsW ith 3 to 5 years of follow-up study,single crown applied to the restoration for residual roots of premolar group had8 9.38%to 71.43%success rate,combined crown 91.45%to 88.60%.The success rate had no difference in 3 years of follow-up study and no significant difference in 5 years of follow-up study withχ 2 test.Conclusion Combined crown hasb etter clinical effect than single crown used to restore residual roots of premolar.