Association Between Serum 25-Hydroxyvitamin D Status and Long-Term Marginal Bone Loss Around Dental Implants

Background and Objectives: The objective was to evaluate the association between serum 25-hydroxyvitamin D [25(OH)D] measured before functional loading and long-term peri-implant marginal bone loss (MBL). Materials and Methods: This retrospective study included 60 systemically healthy patients with 136 implants. Patients were classified as vitamin D-deficient (<20 ng/mL; n = 30) or -sufficient (≥20 ng/mL; n = 30). MBL was calculated from periapical radiographs obtained at prosthetic delivery and final follow-up (mean, 39.46 months; range, 34–48 months). Clinical parameters and implant loss were secondary outcomes. Between-group comparisons used the Mann–Whitney U and Fisher’s exact tests; associations were examined using Spearman’s rank correlation. Results: MBL was greater in the deficient group than in the sufficient group (0.98 ± 0.25 mm vs. 0.42 ± 0.32 mm; p < 0.001). Serum 25(OH)D was inversely correlated with MBL in the deficient group (rs = −0.720), sufficient group (rs = −0.604), and overall sample (rs = −0.862; all p < 0.001). No statistically significant between-group differences were detected in the clinical parameters (all p > 0.05). Conclusions: Lower baseline serum 25(OH)D was associated with greater long-term MBL, while clinical parameters and patient-level implant loss did not differ between groups.