Changes in peri-implant soft tissue levels following surgical treatment of peri-implantitis: A systematic review and meta-analysis

Aim: To assess the changes in peri-implant soft tissue levels after the surgical treatment of peri-implantitis. Methods: Randomized controlled trials, controlled clinical trials, cohort studies and case series, evaluating the changes in the position of the mucosal margin before and after surgical treatment of peri-implantitis, were searched. Secondary outcomes were changes in keratinized mucosa (KM), radiographic bone levels, probing depths (PD), plaque indices, bleeding on probing and patient perception. Meta-analyses were performed to determine weighted mean differences (WMD) or effects (WME). Results: Twenty-six articles, reporting 20 investigations, were included. Reconstructive approaches yielded significantly less increase in mucosal recession, when compared to access flaps (n = 3, WMD = −1.35 mm, 95% confidence interval [CI] [−2.62; −0.07], p =.038). When comparing among reconstructive surgical interventions similar outcomes were observed irrespective of the use of a barrier membrane (n = 3, WMD = −0.01 mm, 95% CI [−0.15; 0.13], p =.917). When considering the effects over time, limited mucosal recession was observed after reconstructive procedures (n = 23, WME = 0.389 mm, 95% CI [0.204; 0.574]), p =.001), while increased recession was reported with either resective or access flap surgery (n = 6, WME = 1.21 mm, 95% CI [0.70; 1.72], p = <.001; and n = 3, WME = 0.95 mm, 95% CI [0.20; 2.10], p =.106; respectively). When resective and reconstructive approaches were combined the highest values on peri-implant recession were reported (n = 2, WME = 1.97 mm, 95% CI [0.81; 3.14], p <.001). Reconstructive surgical interventions were associated with greater radiographic bone level gains, while similar values were reported for PD reduction when comparing reconstructive, access and resective procedures. Conclusions: Resective surgical procedures were associated with significant post-surgical recession while minimal recession was observed in regenerative interventions.