Risk Indicators for Peri-Implant Diseases and Peri- Implantitis Severity: A Cross-Sectional Study on Implants with 5 to 10 Years of Loading

Background: Peri-implant-implant diseases, such as peri-implant mucositis and peri-implantitis, present significant challenges in implant dentistry. A peri-implant mucositis prevalence of 43% and peri-implantitis prevalence of 22% have been reported. While treatment for peri-implant mucositis is generally predictable, peri-implantitis exhibits high recurrence rates and less predictable outcomes, particularly in severe bone loss cases. Identifying critical risk factors is essential for early diagnosis, prevention, and management. Aim: This study aimed to identify the most critical risk indicators for peri-implantitis and peri- implant mucositis within a unified model and assess how these factors are associated with the severity of peri-implantitis. Methods: A cross-sectional study was conducted at the University of Michigan School of Dentistry, involving 202 patients with 405 implants. Data on patient characteristics, systemic conditions, homecare, history of periodontitis, and implant-related variables were collected. Clinical and radiographic examinations determined peri-implant health status. Mixed-effects logistic regression models identified significant risk indicators, while ordinal logistic regression explored associations with disease severity. Results: For peri-implant mucositis, key factors included lack of access for interproximal brushes (OR = 1.44, 95% CI: 1.30-1.98), poor oral hygiene (OR = 3.11, 95% CI: 2.47-3.41), low compliance with professional dental cleanings (OR = 3.12 95% CI: 2.88-3.41), and history of Periodontitis (OR = 2.101, 95% CI: 1.881 - 2.988). Similarly, in peri-implantitis, significant factors were lack of access for interproximal brushes (OR = 2.88, 95% CI: 2.14 – 3.11), poor oral hygiene (OR = 1.98, 95% CI: 1.61- 3.12), low compliance with professional dental cleanings (OR = 2.41 95% CI: 1.93 – 2.88), and history of Periodontitis (OR = 1.87 95% CI: 1.12 – 2.56). 12 For bone-level implants, short abutment height (OR = 2.16, 95% CI: 1.15 – 4.03), high abutment angles >30° (OR = 2.243, 95% CI: 1.249 - 4.028), and shallow implant placement (OR = 4.48, 95% CI: 2.37 – 8.46) were found with significant associations to peri-implantitis. For peri- implantitis severity, factors such as thin peri-implant mucosa (OR = 3.33 95% CI: 2.11 – 3.981), implants in smokers, (OR = 4.14, 95% CI: 2.04 – 7.14), posterior implant position (OR = 10.140, 95% CI: 3.340 - 15.870), and shallow implant placement (OR = 2.81, 95% CI: 2.19 – 4.19) were significantly associated with severe peri-implant bone loss >50%. Conclusion: This study identified the most critical risk indicators for peri-implant mucositis and peri-implantitis, including inadequate oral hygiene, history of periodontitis. In bone level implants implant implant restoration factors, such as short abutments <2 mm, high abutment emergence agles >30°, and shallow implant placement were identified as risk indicators for peri- implantitis. For peri-implantitis severity, the key factors were thin peri-implant mucosa, smoking, posterior implantplacement, and shallow implant placement.