The assessment of different high-dose topical fluoride gels on in vitro remineralization of radiated demineralized dentin

Objective: This study investigates the efficacy of an experimental 1.1% sodiumfluoride (NaF) toothpaste in gel form, with and without Sr/F bioactive glass nanoparticles(Sr/F-BGNPs), in remineralizing radiated demineralized dentin.Materials and method: Fourteen extracted third-molar, subjected to a standardradiotherapy protocol (2 Gy/day, 70 Gy cumulative) with Volumetric Modulated ArcTherapy (VMAT) technique. The crowns were cut to two millimeters of dentin disc anddivided into four pieces to produce four groups (n=14/group). The specimens weredemineralized with 17%EDTA for six hours. Treatments included Group1: Deionizedwater (DI), Group2: Experimental 1.1 NaF toothpaste (E5000), Group3: Experimental 1.1toothpaste with 1wt% Sr/F-BGNPs, and Group 4: Commercial toothpaste (Prevident, PV),applied twice daily during a 14-day pH-cycling protocol. Remineralization of dentin wasassessed using Fourier-transform infrared spectroscopy (FTIR-ATR) and scanningelectron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX). Moreover, thestability of the tested materials was examined using fluoride release and pH levelassessments.Results: PV showed a significantly higher mineral-to-matrix ratio after 14 dayscompared to other groups (p<0.05). E5000+BG also demonstrated increasedremineralization over its E5000 (p=0.04). SEM/EDX observations indicated silica-basedcompound precipitation in the dentinal tubules in the E5000+BG and PV groups.Furthermore, adding Sr/F-BGNPs increased the pH level but reduced the fluoride releasefrom the materials.Conclusion: The addition of Sr/F-BGNPs enhanced the remineralizing effect ofthe experimental materials. However, all the experimental materials significantly lowertheir remineralizing actions compared to the commercial material (PV). These findingshighlight the potential utility of high-concentration fluoride toothpaste in managingaggressive radiation caries in Thailand.