Hypervitaminosis D is correlated with adverse dental implant outcomes: A retrospective case-control study.

Objectives: To investigate vitamin-D levels effect on the survival/success and on marginal bone levels of dental implants.

Methods: Patients with peri-implant disease and healthy control patients with functionally loaded dental implants were included in this retrospective case-control study. Forty patients with 201 implants were in the diseased-cohort, while thirty-three patients with 90 implants were in the control-cohort. Patient blood 25(OH)D levels were assessed through quantitative blood test. The correlation between abnormal 25(OH)D levels and disease status of each patient was assessed using Fisher's exact tests. The correlation of each implant's outcomes with vitamin-D status was assessed using Kaplan-Meier survival analysis and Mann-Whitney U tests.

Results: Patients with blood 25(OH)D levels >70 ng/mL (hypervitaminosis-D) had a 21.1-fold increase in the risk of implant failure or severe peri-implant bone loss regarding patients with intermediate (>30, ≤70 ng/mL) levels. Kaplan-Meier survival analysis revealed that implants in the hypervitaminosis-D cohort had a survival probability of 73.7 % (95 % CI:56.5-84.5 %) at 19-years after surgery, compared to 95 % for implants in patients with intermediate 25(OH)D levels (95 % CI:88.3-97.9 %). Additionally, implants in the hypervitaminosis-D cohort lost bone faster than implants in the intermediate cohort. These results were specific to the patient cohort with elevated blood 25(OH)D levels and not observed in patients taking vitamin-D supplementation. The impact of hypervitaminosis-D was enriched for implants in the maxilla, and not as apparent for implants in the mandible.

Conclusions: Blood 25(OH)D levels >70 ng/mL were correlated with adverse implant outcomes, including implant failure and peri-implant bone loss, especially in the maxilla.

Clinical Relevance: These results suggest that hypervitaminosis D may be a previously unidentified risk factor for dental implant complications and should be further investigated to elucidate the underlying mechanism.