Analysis of the risk of interproximal contact loss between adjacent teeth and implant-supported fixed prostheses: A retrospective cross-sectional study

Food impaction following the placement of an implant-supported restoration is most frequently associated with a high incidence of interproximal contact loss (ICL). Food packing is unpleasant and can cause gingival inflammation and even peri-implant bone resorption. Studies on the various factors that may contribute to the occurrence of ICL are lacking. This retrospective cross-sectional study aimed to collect and analyze data from participants to investigate the incidence of ICL between implant-supported prostheses and adjacent teeth. The study further sought to identify factors influencing ICL, evaluate participants' subjective perceptions of ICL, and explore the relationship between ICL and peri-implant tissue health. A total of 107 participants with 133 implant-supported fixed prostheses (ISFPs) and 172 interproximal contact relationships, all verified at the time of insertion, were included in this study. A total of 27 factors were assessed in 4 dimensions: participant, ISFP, adjacent tooth, and antagonist. The Spearman correlation analysis, linear-by-linear association chi-squared test, Pearson chi-squared test, and Fisher exact test were used to analyze the factors influencing the ICL (α=.05). ICL was found to occur as early as 3 months after delivery of an ISFP, with a mean onset of 24 months after delivery. The prevalence of ICL at the participant level was 66.4% and 53.4% at the ISFP level, and the incidence of ICL was higher on the mesial side than on the distal, at 50.5% and 36.9%. Statistically significant differences were found in relation to the contralateral side, root configuration of the distal adjacent tooth, a plunger cusp, and participants' awareness of food impaction (P<.05). Additionally, a significant correlation was found with the delivery time (P<.05). Delivery time, the contralateral side, root configuration, and an opposing plunger cusp can influence the development of mesial ICL. However, no significant relationship was found between ICL and peri-implant tissue health. Additionally, participants' awareness of food impaction was found to be associated with the occurrence of mesial ICL.