Objective To investigate the effect of treatment on peri-implant disease progression, with particular emphasis on the differential outcomes based on baseline disease severity.

Materials and Methods This retrospective analysis examined 323 patients with 1003 implants treated between 2010-2024. Clinical data included probing depths, radiographic bone loss measurements, and treatment interventions. Implants were categorized as healthy, peri-implant mucositis, or peri-implantitis. Treatment modalities were classified as no treatment, non-surgical therapy, prophylaxis/maintenance, or surgical therapy. Statistical analysis employed chi-square testing and multivariate regression modeling using JMP Pro 17.1 software, with significance set at p<0.05. Mean follow-up was 7.8 years (range 0-20 years).

Results The cohort comprised 47.6% females and 52.3% males with mean age 76.6±10.9 years. Progressive increases in probing depths (3.0mm to 3.6mm) and bone loss (7-10% to >25%) occurred over time regardless of maintenance status. Maintenance therapy showed no statistically significant protective effect against bone loss, with overlapping confidence intervals between maintenance and no-maintenance groups. Treatment effectiveness varied dramatically by baseline disease severity: all modalities remained stable in healthy tissues or early mucositis (≤4mm probing depths) but showed severely diminished long-term effectiveness once peri-implantitis was established (>5mm probing depths). Surgical therapy initially improved moderate cases but demonstrated progressive deterioration after 8.3 years. Advanced peri-implantitis cases (>7mm probing depths) showed limited response to all treatment approaches.

Conclusion Treatment effectiveness becomes severely compromised once peri-implantitis is established, regardless of therapeutic modality. Early intervention during the mucositis phase remains crucial, as conventional treatments fail to provide sustained benefits in established peri-implantitis. These findings challenge current treatment paradigms and suggest that clinical practice should prioritize prevention and aggressive early intervention over treatment of advanced disease. The data supports a fundamental shift toward risk-based maintenance strategies focused on preventing disease progression rather than treating established peri-implantitis.