(214) Dental Restoration and Associations with Leukoplakia and Head and Neck Cancer: a Propensity-Matched Cohort Study

Introduction: Dental restorations represent chronic oral exposures considered safe, yet population-level data on associations with oral precancerous lesions and malignancy remain limited. Understanding these associations is essential for patient counseling and materials selection.

Methods: Retrospective cohort analysis using TriNetX evaluated whether dental restorations modified incident oral cavity cancer, salivary gland cancer, and leukoplakia risk. Patients receiving fillings (direct: amalgam/resin; indirect: crowns/inlays) before 2021 with ≥5-year follow-up were compared to controls receiving dental care without restorations. Cohorts were propensity-matched 1:1 for demographics, tobacco/alcohol use, socioeconomic factors, comorbidities, and dental caries.

Results: Among 97,342 matched pairs, dental fillings were associated with increased leukoplakia (0.13% vs 0.08%, HR 1.50[1.12-2.00], p=0.006) and salivary gland cancer (HR 1.93[1.02-3.67], p=0.04). Direct restorations showed increased leukoplakia (HR 1.46, p=0.010) and oral cavity cancer (0.08% vs 0.05%, HR 1.48[1.02-2.15], p=0.037). Resin composites (HR 1.70, p=0.001) and amalgam (HR 1.62, p=0.070) showed elevated leukoplakia. Indirect restorations demonstrated strongest leukoplakia association (HR 2.21, p=0.011). Leukoplakia increases occurred in ages 18-60 (HR 1.79, p=0.015) but not ≥60 years.

Conclusions: Dental restorations are associated with increased leukoplakia and modest salivary gland cancer elevation, though absolute risks remain small. Direct restorations demonstrated oral cavity cancer risk not reproduced in material-specific analyses of amalgam or resin. Leukoplakia increases limited to younger patients despite expected cumulative exposure effects suggest non-causal mechanisms such as selection bias.