Prevalence and risk factors of interproximal contact loss between implant-supported prostheses and adjacent teeth in posterior dentitions: a retrospective study

Dental implant therapy is widely used to restore dentition defects or loss, however, as a complication of it, interproximal contact loss (ICL) has not been adequately studied. To explore the prevalence of ICL between implant-supported prostheses and adjacent teeth, and to analyze the risk factors for ICL. Two hundred and four participants who received 445 implant-supported prostheses from January 2011 to December 2020 were enrolled in the study. Aluminum strips of different thicknesses were used to determine the interspace between the implant-support prostheses and the adjacent teeth. Medical records of implant prostheses and participants were reviewed. Periodontal condition, occlusion, and additional factors were examined. Statistical analyses were performed to estimate the prevalence rate of ICL and its influential factors. The prevalence of ICL was 59.8% at the patient level for 10-years function duration and increased over time. For the mesial site, the prevalence of ICL was 40.0% and food impaction (OR = 4.991, P < 0.001), adjacent teeth status (OR = 4.062, P = 0.042), function duration (OR = 1.299, P < 0.001) and bruxism (OR = 2.098, P = 0.034) were independent risk factors. For the distal site, the prevalence of ICL was 24.1% and food impaction (OR = 2.809, P = 0.002), mechanical complications (OR = 7.041, P < 0.001), bruxism (OR = 2.356, P = 0.019) and peri-implantitis (OR = 2.385, P = 0.021) were independent risk factors for ICL. ICL was found to increase over time and was more common at the mesial site than at the distal site. Food impaction, function duration, adjacent teeth status, implant mechanical complications, bruxism and peri-implantitis were risk factors for ICL.