Effect of preventive dental treatment on caries incidence in patients receiving head and neck radiation therapy: a systematic review

Head and neck cancer patients receiving radiotherapy (RT) are at high risk of radiation-induced dental caries (RIC). Preventive dental interventions are employed to mitigate this complication, though their relative effectiveness varies across the literature. To systematically review the impact of preventive dental treatments on dental caries incidence among patients undergoing head and neck RT. Following PRISMA 2020 guidelines, PubMed, Embase, and Cochrane Library were searched (2000–June 2025) for studies reporting post-RT caries outcomes. Eligible designs included randomized controlled trials (RCTs), cohort, and observational studies. Due to significant heterogeneity in study designs and interventions, a qualitative synthesis was conducted. Eight studies involving over 1,100 patients were included. Evidence suggests that pre-RT dental optimization combined with daily topical fluoride is associated with reduced caries incidence compared to minimal prevention. Observational data indicated caries rates generally remained lower in adherent preventive cohorts (often < 15%) compared to non-compliant or historical controls (ranging up to 80–100%), though direct comparative evidence is limited. One RCT suggested potential benefits of casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) over fluoride mouth rinse. Additionally, modern intensity-modulated radiation therapy (IMRT) was associated with reduced xerostomia and lower caries risk compared with conventional RT. Patient adherence and radiation dose to dental structures were identified as key factors influencing outcomes. Preventive dental care—encompassing pre-RT optimization, daily topical fluoride, and modern RT techniques—appears to substantially reduce the burden of radiation-related caries. However, given the heterogeneity of the evidence, results highlight the importance of multidisciplinary collaboration and lifelong patient adherence within structured oral oncology protocols rather than reliance on a single intervention.