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 = 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.