Factors associated with the survival and marginal bone loss of dental implants: a 5-year retrospective study

ABSTRACT

PURPOSE: The purpose of this study was to compare the long-term survival rate and peri-implant marginal bone loss related to multiple risk factors including the clinician's experience. MATERIALS AND METHODS: Four hundred twenty implants in 146 patients, who had involved a supportive periodontal therapy program every 3 to 6 months and had follow up data for at least 5 years, were selected as the study group. Peri-implant marginal bone loss, data of demographic, implant and surgical characteristics were collected from peri-apical radiographs and chart review. Implant survival was regarded as the remaining with radiographic marginal bone level in excess of 50% of the fixture length for any reason. RESULTS: The cumulative survival rate after 5 years of loading was 94.9%. In binary logistic regression analysis, smoking status (P = 0.033) and presence of spontaneous cover screw exposure (P < 0.001) were significantly related to 5-year survival of implants. In stepwise multiple regression analysis, smoking status (P < 0.001), type of abutment connection (P < 0.001) and implant surface (P = 0.033) were significantly related to peri-implant marginal bone level. And the year of resident was not statistically related to 5-year implant survival in simple logistic regression analysis (P = 0.171). CONCLUSION: Smoking status, spontaneous cover screw exposure, type of abutment connection and implant surface might influence the implant success. There was no significant correlation between the year of resident and implant failure.