Evaluation of the efficacy of low concentration fluoride gel using custom trays to prevent radiation-related dental caries in patients with head and neck cancer: protocol for a randomised controlled phase III trial (FluCar study)

INTRODUCTION: The present study is a randomised, multicentre, open-label, phase III study, to evaluate the efficacy of low concentration of fluoride gel, applied using custom trays, in preventing radiation-related dental caries in patients with head and neck cancer who have undergone or are undergoing radiotherapy. METHODS AND ANALYSIS: Patients will be randomised into fluoride and control groups (1:1 ratio). In the fluoride group, patients will wear custom trays loaded with 0.145% fluoride gel after brushing every night while sleeping. In the control group, patients will receive oral hygiene instructions as usual. Patients in both the groups will be followed up every 3 months for 1 year. The primary endpoint is the incidence of newly developed dental caries. Target accrual is 80 patients with a two-sided type I error rate of 5% and 80% power to detect 80% risk reduction. ETHICS AND DISSEMINATION: This study was approved by the Clinical Research Review Board in Nagasaki University The protocol of this study was registered at Japan Registry of Clinical Trials (jRCT) and University hospital Medical Information Network Clinical Trials Registry (UMIN). The datasets generated during the current study will be available from the corresponding author on reasonable request. TRIAL REGISTRATION NUMBERS: jRCTs 072190039 and UMIN000041426