Improving Enamel Acid Resistance by an Intraoral Fluoride-Release Device Incorporating Cationic Hydroxy Cellulose Gel Using 3D Printer Molding

An intraoral fluoride-releasing device (IFRD) is a cost-effective tool for introducing fluoride into the oral cavity. It allows prolonged uptake of low concentrations of fluoride into teeth. We developed a new IFRD using 3D additive manufacturing and a new low-release fluoride gel. Gels for IFRDs were synthesized from hydroxyethyl cellulose (SE600) and cationic hydroxyethyl cellulose (L200). We compared the effects of the new cationic fluoride slow-release gel and non-cationic gel on enamel acid resistance in vitro. Cationization significantly increased fluoride ion concentration, as evident from its concentrations of 0.68 ± 0.08 ppm for SE600 and 4.24 ± 0.83 ppm for L200 after 60 min of immersion in distilled water. In addition, the acid resistance of bovine tooth enamel post-application was analyzed by measuring tooth loss, mineral loss (ΔZ), and lesion depth (Ld) using polarized light microscopy, electron microscopy, and micro-radiography. Compared to the SE600 group, the cationic L200 group had significantly reduced ΔZ and Ld, enhancing enamel acid resistance. This device could be implemented in areas where adequate oral care is challenging, including preventive dentistry, ward management, nursing homes, and dental clinic visits.