In vitro remineralization of artificial enamel caries with resin composites containing calcium phosphate particles

The aim of the study was to evaluate the effect of experimental composites containing dicalcium phosphate dihydrate (DCPD) on remineralization of enamel lesions. Five resin-based composites containing equal parts (in mols) of bisphenol-A glycidyl dimethacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA), and 60 vol % of fillers were manipulated. Filler phase was constituted by silanized barium glass and 0, 10, or 20 vol % of DPCD particles, either functionalized (F) or nonfunctionalized (NF) with TEGDMA. Artificial subsurface lesions were produced in human enamel fragments and divided according to the resin composite applied on the lesion (no DCPD, 20% NF, 20% F, 10% NF, 10% F) plus a group without composite build-up (nontreated, NT). Fragments were exposed to 16 days of pH cycling. Specimens were evaluated using transverse microradiography (TMR). Calcium and phosphate concentrations in pH-cycling solutions were determined by spectrophotometry. TMR and ionic concentrations were analyzed using one-way ANOVA/Tukey and Kruskal-Wallis/Dunn test, respectively (alpha: 0.05). All composite groups showed enamel remineralization (3%-23%). Higher mineral recovery in the middle (7%-11%) and bottom (2%-7%) thirds of the lesion was observed in groups with DCPD-containing composites compared to the "no DCPD" group (middle: 1%, bottom: -3%). Lesion depth was significantly reduced in groups using DCPD-containing composites compared to NT group. No noticeable increase in calcium and phosphate ions was observed in the pH-cycling solutions due to the presence of DCPD in the composites. In conclusion, composites with DCPD fractions as low as 10%, regardless of functionalization, were able to promote mineral recovery and reduce lesion depth of enamel lesions. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1542-1550, 2019.