Interproximal contact loss in a retrospective cross-sectional study of 4325 implants: Distribution and incidence and the effect on bone loss and peri-implant soft tissue

Abstract

Statement of problemInterproximal contact loss (ICL) is a common finding between implant restorations and teeth, yet few reports have been published on incidence or related complications. PurposeThe purpose of this cross-sectional retrospective study was to measure the ICL of 4325 implants, including single and multiple splinted restorations. Material and methodsData on 4325 implants were extracted from patient records on ICL, time of follow-up, implant location, and sex of the participant for whom implants were placed in a private practice between 1999 and 2016. Periapical radiographs were used to evaluate the crestal bone level (CBL), whereas peri-implant soft tissues were evaluated with the implant mucosal index (IMI). Measurements (ICL, IMI, and CBL) were evaluated with an average follow-up of 4.5 years (range: 0.25 to 21 years). ICL was assessed in relation to the implant location and sex and grouped by the last clinical recall (1, 2-3, 4-5, 6-7, or 8+ years) to evaluate the effect of time. Data were analyzed by the chi-square test (α=.05). ResultsOverall, 17% of implants had ICL, and this significantly increased over time from 11% at 1 year to 29% at ≥8 years (chi-square: 123.8, P<.001). Mandibular implants had more ICL (20%) than maxillary implants (15%) (chi-square: 17.5, P<.001), whereas no difference was found between molar and premolar sites or male and female participants. There was no significant effect of ICL on CBL over time, but there was an increase in inflammation with higher IMI scores at ICL sites. ConclusionsThe incidence of implant ICL was found to be 17%, and ICL was found to increase over time up to 27% at ≥8 years of follow-up. ICL was more common in posterior and mandibular sites. ICL was shown to increase soft tissue inflammation but was not found to affect implant CBLs.