Proximal Contact Loss in Implant-Supported Restorations: A Systematic Review and Meta-Analysis of Prevalence

Purpose: This is a systematic review and meta-analysis to estimate the overall prevalence of Proximal Contact Loss (PCL) and determine the distribution and clinical features of proximal contact loss. Methods: This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. As this was a systematic review of prevalence, the condition, context, and population framework was followed. The focus question was: What is the prevalence and distribution of PCL in implant-supported restorations? Two investigators independently examined the literature in four databases (Medline, Scopus, Web of Science, and Cochrane) for suitable articles published before November 11, 2020, with no start-date restriction; an additional search was conducted by hand. A standardized data extraction chart was utilized to extract the relevant information from the selected studies. Results: Fifteen studies met the inclusion criteria. A total of 11,699 restorations were evaluated in the final sample. The overall prevalence was 20% at the implant-restoration level (among 4984 implants) and 26.6% at the contact point level (among 2603 contact points). The frequency of proximal contact loss was higher on the mesial side, both at the implant-restoration level (13.8%) and at the contact point level (21.9%), than on the distal side, where the prevalence was 3.3% and 11.0%, respectively. The event rate in the maxilla and in the mandible at the contact level was 21.4% and 21.9%, respectively. Conclusions: Proximal contact loss is a frequent complication. Approximately, 29% of contact points develop this condition, which may cause food impaction and damage to the interproximal tissues.