Evaluation of factors affecting the success rate of orthodontic mini-implants by survival analysis

摘要

AIM: To investigate the success rate of mini-implants and its characteristics and risk factors by survival analyses. METHODS: Three hundred and ninety-four miniimplants of the same type were placed by a single clinician. Age, gender, treatment duration, time of failure, side and jaw of implantation and the soft tissue at placement site were recorded. Odds ratio, survival curves, and Cox proportional hazard model were applied to evaluate the factors influencing the miniimplants' success rate. RESULTS: The cumulative success rate was 88.1%.The maxilla had a significantly higher success rate than that of the mandible(91.7% vs 83.7%, respectively, P = 0.019). Placement of mini-implants in the attached gingiva(AG) showed a higher success rate than that of the mucogingival junction(MGJ) and mucous membrane(MM)(AG, 94.3%; MGJ, 85.8%; MM, 79.4%; P < 0.001). Significant association was found between the jaw and the gingival tissue type(P < 0.001). There were no significant differences between maxilla and mandible when compared within each placement site.CONCLUSION: The gingival tissue type had the most significant effect on the success rate of the mini-implant with higher success rate in the attached gingiva.