Interproximal contact loss at implant sites: a retrospective clinical study with a 10‐year follow‐up

Aim To assess the frequency and quantity of interproximal contact loss (ICL) between implant restorations and adjacent teeth after at least 10 years of follow‐up (FU). Methods Thirty‐nine patients (median age 57.3 years) with 80 implants were re‐examined at least 10 years after insertion of final restorations (single crowns or fixed dental prostheses (FDPs)). Baseline (insertion of the restorations) and FU examinations encompassed the following: Stone casts were scanned and superimposed for metric assessment of tooth movements, radiographs, and clinical measurements. Outcome measures at implant sites were as follows: the extent of tooth movement and the frequency of interproximal contact loss [ICL], peri‐implant marginal bone levels [MBLs], and clinical measurements (plaque control record [PCR], Bleeding on Probing [BOP], and probing depth [PD]). Data were analyzed statistically with generalized regression modeling with robust standard errors to account for within‐patient clustering at 5%. Results Interproximal contact loss for at least one contact point after 10 years was observed in 50% of all implants (with open interproximal spaces up to 1.64 mm). Mesial contact points were significantly more prone to ICL than distal ones (relative risk [RR] = 1.79; 95% confidence interval [CI] = 1.07–2.99; p = .03). The type of restoration had a significant effect on ICL, with FDPs of 2 implants being significantly more prone to mesial ICL than single crowns (RR = 1.52; 95% CI = 1.02–2.25; p = .04). ICL was also associated with a significant increase in PD (+0.46 mm (95% CI = 0.04–0.88 mm; p = .03)) compared to implant sites without ICL. BOP, MBLs, and PCR were not significantly influenced by ICL. Conclusion Interproximal contact loss was a common finding in 50% of the implant sites and was significantly associated with an increase in PD.