Development and Characterization of Fluoride-Enhanced Dental Composites for Improved Enamel Remineralization

Abstract

Aim: This study investigates how varying levels of MCPM, and NaF with fixed level of CaO affect dental composite properties, including polymerization kinetics, long-term density, water sorption, pH, mechanical performance, and fluoride release. Methods: Five experimental composite formulations were prepared with varying concentrations of monocalcium phosphate monohydrate (MCPM), sodium fluoride (NaF), and calcium oxide (CaO), with the remaining fraction consisting of inert glass filler. The formulations were: F1 (F888), F2 (F848), F3 (F488) F4 (F448) and F5 (F000) where the first second and third numbers indicate the weight percentages in the filler phase of MCPM, NaF and CaO respectively. Polymerization kinetics were assessed by ATR-FTIR (n = 4) at 1 mm depth. Disc specimens (10 mm × 1 mm) were used to measure mass and volume changes (n = 3). Solution pH (n = 3) and fluoride release (n = 3) were monitored over time. Biaxial flexural strength and modulus were measured (n = 8) for samples stored in water at 37 °C up to 2 months. Results: All formulations showed high final monomer conversion (80–90%) with no effect of CaO, MCPM, or NaF on curing kinetics. Densities ranged 1.87–1.97 g/cm³, decreasing with higher filler content. Mass and volume increased over time, levelling for F000 but continuing for other formulations. Storage pH was 6-8 initially, later rising for F3 and F4 and slightly declining for F5. Fluoride release was highest in F1 and F3 (50–57), moderate in F2 (34), and minimal in F4 (25). Flexural strength and modulus were highest in F5 (200 MPa, 4.8 GPa), while F1–F4 were lower (90–120 MPa, 3.0–4.0 GPa), with F1 and F2 declining most over 2 months. Conclusion: The composites exhibited high monomer conversion, stable mechanical properties, and neutral pH. MCPM increased mass and volume, and NaF provided sustained fluoride release, supporting their use for pulp capping and restoration.