An Evaluation of the Peri-Implant Tissue in Patients Starting Antiresorptive Agent Treatment After Implant Placement: A Nested Case–Control Study

Background and Objectives: We wished to evaluate the effect of antiresorptive agents (ARAs) on peri-implant tissues and to examine the risk factors for peri-implant medication-related osteonecrosis of the jaw (MRONJ). Materials and Methods: The study cohort consisted of patients who underwent implant surgery or maintenance treatment between March 2012 and December 2024. The patients were divided into two groups: those in whom bisphosphonates (BPs) or denosumab (Dmab) was used to treat osteoporosis after implant treatment (the ARA group) and a control group. Peri-implant clinical parameters (implant probing depth (iPPD), implant bleeding on probing (iBoP), marginal bone loss (MBL), and mandibular cortical index (MCI)) measured at the baseline and at the final visit were statistically evaluated and compared in both groups. Risk factors were examined using a multivariate analysis of adjusted odds ratios (aORs). Results: A total of 192 implants in 61 patients (52 female, 9 male) were included in this study. The ARA group consisted of 89 implants (22 patients). A comparison of the clinical parameters showed that the ARA group had significantly higher variations in their maximum iPPD and iBoP values over time than those in the control group. Risk factors for peri-implantitis as objective variables were the use of ARAs (aOR: 3.91; 95% confidence interval [CI]: 1.29–11.9) and the change in the maximum iPPD over time (aOR: 1.86; 95% CI: 0.754–4.58). Conclusions: During long-term implant maintenance treatment, patients’ health and medication status change. Monitoring peri-implantitis, the presumed cause of peri-implant MRONJ, is essential, especially in patients who started ARA treatment after implant placement, and special attention should be paid to changes in implant pocket depth.