Outcome indicators of non-surgical therapy of peri-implantitis: a prospective case series analysis

Objectives This study aims to identify patient and implant indicators influencing the non-surgical therapeutic outcomes of peri-implantitis at 6 months of follow-up. Methods This case series involved patients with at least one implant diagnosed with peri-implantitis according to the 2017 World Workshop criteria. Non-surgical therapy consisted of mechanical debridement of the peri-implant pockets combined with metronidazole 500 mg 3 times a day for 7 days. At baseline and at 6 months, clinical and radiographic variables were collected to calculate treatment success (probing pocket depth reduction to 5 mm without bleeding on probing or < 5 mm irrespective of bleeding on probing at all implant sites, and lack of bone loss progression). The primary outcome was treatment success (%) at 6 months. The influence of the patient and implant/prosthetic variables upon disease resolution was assessed through simple and multiple logistic regression analyses at patient and implant level, using generalized estimation equations models. Results A total of 74 patients and 107 implants were analyzed at 6 months. Disease resolution was established in 25.7% of the patients and 24.1% of the implants. Patients with stage IV and grade C periodontitis, inadequate oral hygiene at baseline, and wide diameter (≥ 4.5 mm) presented significantly greater treatment failure, whereas smokers and former smokers demonstrated a tendency toward failure. At 6 months, there was a significant decrease in probing pocket depth and bleeding on probing of 1.08 ± 1.06 mm and 14%, respectively. Radiographically, a significant gain in marginal bone level of 0.43 ± 0.56 mm was observed. Conclusion Disease resolution after non-surgical treatment of peri-implantitis is negatively influenced by the loss of support of the adjacent periodontium, poor baseline oral hygiene, and wide diameter implants (≥ 4.5 mm). Clinical relevance This study helps to discriminate the clinical situations in which non-surgical treatment is less likely to achieve treatment success at short term.