Intraoral fluoride retention after using experimental toothpaste containing titanium tetrafluoride and chitosan

OBJECTIVES: This clinical study evaluated the intraoral fluoride retention using Titanium tetrafluoride (TiF4)/Chitosan (Ch) toothpaste. MATERIALS AND METHODS: Participants (n = 20) were randomly divided into double-blind and crossover phases according to the toothpastes: (1) TiF₄/Ch (1400 ppm F-, pH 4.5, 0.5% chitosan); (2) TiF₄ (1400 ppm F-, pH 4.5); (3) Elmex® Caries Protection (positive control, 1450 ppm F-, AmF, pH 4.5); and (4) Placebo (negative control, pH 7.0). Each participant received all treatments, with a 7-day washout period between phases. After seven days, stimulated saliva and biofilm samples were collected 1 h and 12 h after brushing. Fluoride concentrations (ppm F-) were determined with specific electrodes and statistically analyzed (ANOVA/Tukey, p < 0.05). RESULTS: After 1 h, TiF₄/Ch toothpaste increased the mean fluoride levels in saliva (4.33 vs. 0.81 ppm for the placebo), biofilm fluid (0.25 vs. 0.18 ppm), solid biofilm (12.66 vs. 3.73 ppm), and total biofilm (22.14 vs. 3.19 ppm), similarly to TiF₄ and Elmex®. After 12 h, mean fluoride levels in saliva and biofilm fluid returned to baseline, while elevated levels persisted in the solid biofilm (8.29 vs. 3.15 ppm) and total biofilm (6.57 vs. 2.03 ppm). CONCLUSIONS: TiF₄/Ch toothpaste maintained fluoride retention in stimulated saliva and biofilm, similarly to the TiF4 and Elmex®. Fluoride retention in saliva and biofilm fluid was observed at 1 h after use, whereas in biofilm it persisted for 12 h. CLINICAL RELEVANCE: TiF₄/Ch toothpaste showed prolonged fluoride retention in biofilm, comparable to the commercial toothpaste, supporting its potential as an alternative for maintaining intraoral fluoride reservoirs. TRIAL REGISTRATION: This study was registered at the Brazilian Registry of Clinical Trials (ReBEC) under number RBR-3f5c5hx.