Surface wear and roughness of experimental composites containing calcium orthophosphate particles following toothbrush abrasion

This study evaluated experimental composites containing dicalcium phosphate dihydrate (DCPD) particles for toothbrush wear and roughness. Composites containing bisphenol-A glycidyl dimethacrylate/triethylene glycol dimethacrylate with 50 vol% inorganic fraction consisting of barium glass and DCPD (35:15 and 15:35 vol%) or barium glass only were tested alongside a commercial composite (Beautifil II, Shofu) and a glass-ionomer cement (GIC, Fuji Gold Label 9, GC). Surface loss and roughness were quantified after 50,000 and 100,000 cycles using optical profilometry. The specimens were observed under scanning electron microscopy. Data were analyzed by two-way analysis of variance/Tukey test. After 50,000 cycles, surface loss was higher for the 35% DCPD composite compared to the experimental control and the GIC. After 100,000 cycles, composites with DCPD presented surface loss not different than the commercial composite but higher than seen for the experimental control and the GIC. Roughness for the composite with 35% DCPD was not different than that of the GIC at baseline, which was higher than seen for the other materials. After 100,000 cycles, roughness for the materials containing DCPD and the GIC were not statistically different. In conclusion, the results suggest that DCPD-containing composites would be better suited for restoration of deciduous teeth and low load-bearing restorations in permanent teeth.