Objective: To study the prognostic factors in Full crown restoration of Premolars with cervical defect by analyzing long-term survival. Methods: A total of 432 Premolars with cervical defect, selected from 2012 Jan to 2014 Dec, were restored by Full crown. According to different repair methods, they were divided into resin repair group and post core repair group. The effect was analyzed by Cox regression analysis in 5-year follow-up. Results: Different repair methods (RR=0.567, 95% CI: 0.355~0.907), Teeth contact (RR=0.033, 95% CI: 0.016~0.840), Abutment teeth (RR=0.494, 95% CI: 0.308~0.793), Dentin shoulder collar (RR=11.465, 95% CI: 6.653~19.759), Defect size RR=0.386, 95% CI: 0.187~0.798) were the isolated factor influencing the prognosis. Further subgroup analysis shows that, the survival rate of the affected teeth as abutments restored with single crown fixed dentures is higher than that restored with fixed bridge dentures (χ<sup>2</sup>=4.141, P =0.0419). The survival rate of reinforced abutments restored with fiber posts is higher than that of reinforced abutments restored with metal posts (χ<sup>2</sup>=18.12, P =0.0001)。The C-index of the nomogram for prognosis was 0.838. Conclusion: In order to improve the long-term preservation rate, different restoration methods for Premolars with cervical defect should be selected according to different situations.
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