Periodontal Disease and Risk of Osteoradionecrosis in Patients with Head and Neck Cancer Undergoing Radiotherapy: A Systematic Review and Meta-Analysis.

Background: Osteoradionecrosis (ORN) is a severe late complication of radiotherapy for head and neck cancer, associated with impaired bone healing, infection, pain, and exposed bone. Periodontal disease may contribute to ORN by maintaining inflammatory and infectious foci within irradiated tissues with reduced vascularity and repair capacity. Objective: To evaluate whether periodontal disease or poor periodontal status is associated with increased ORN risk in patients with head and neck cancer undergoing radiotherapy. Methods: This systematic review and meta-analysis followed PRISMA 2020 recommendations and was structured according to the PECO framework. Searches were conducted in PubMed/MEDLINE, Embase, Scopus, Web of Science, Cochrane Library, ClinicalTrials.gov, WHO databases, and gray literature. Observational studies involving head and neck cancer patients treated with radiotherapy and reporting periodontal status in relation to ORN were included. Risk of bias was assessed using a domain-based approach. Random-effects models estimated pooled relative effect estimates and ORN prevalence. Results: Six studies were included in the primary association meta-analysis. Periodontal disease was significantly associated with increased ORN risk, with a pooled relative effect estimate of 4.83 (95% CI: 1.96-11.93; p = 0.0006; I2 = 50.4%). Seven studies including 1785 patients and 118 ORN events were included in the prevalence meta-analysis, showing a pooled ORN prevalence of 9% (95% CI: 6-13%; I2 = 78.0%). Conclusions: The findings suggest that periodontal disease or poor periodontal status may be associated with an increased likelihood of ORN in patients with head and neck cancer undergoing radiotherapy. Given the observational nature of the evidence and the moderate between-study heterogeneity, this association should be interpreted cautiously. Comprehensive periodontal assessment and long-term oral surveillance may be considered as components of multidisciplinary care before and after radiotherapy.