Radiation Therapy for Head and Neck Cancer Leads to Gingival Recession Associated With Dental Caries

OBJECTIVE: To examine effects of Radiation therapy (RT) for Head and Neck Cancer (HNC) on periodontal disease and relationships to caries. METHODS: Multicenter prospective observational cohort study conducted in patients undergoing RT for HNC. Assessments conducted by calibrated examiners at the pre-RT (baseline) visit (n=533), the 12-month visit (n=414), and the 24-month visit (n=365). RESULTS: Average whole mouth mean(SE) distance from the cemento-enamel junction to the gingival margin (CEJ-GM) decreased significantly from 0.43(0.04) mm at baseline to 0.24(0.04) mm at 12 months, and 0.11(0.04) mm at 24 months (p-values ≤0.001). Whole mouth mean(SE) percentage of sites with CEJ-GM distance of less than 0 mm increased significantly from 23.3%(1.0%) at baseline, to 28.5%(1.0%) at 12 months, and 30.5%(1.1%) at 24 months (p-values ≤0.02). Higher mean radiation dose to the mandible was associated with greater increase in percentage of mandibular sites with CEJ-GM distance of less than 0 mm (p=0.003). Both mean CEJ-GM distance and percentage of sites with CEJ-GM distance less than 0 mm were strongly associated with whole mouth mean proportion of decayed, missing, and filled surfaces, as well as proportion of decayed or filled facial/buccal surfaces specifically, (p-values