Investigating the effect of casein phosphopeptide-amorphous calcium phosphate, fluoride varnish, and diode laser on enamel microhardness

ABSTRACT Background: Laser therapy with fluoride-containing material, such as casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), is a new technique for caries prevention. The purpose of this study is to investigate the effect of CPP-ACP, fluoride varnish (FV), and diode laser (DL) on the microhardness of enamel. Materials and Methods: This in vitro study involved 18 extracted human premolar teeth. The teeth were split into buccal and lingual halves. Baseline microhardness was measured using the Vickers hardness test before any intervention. The samples were randomly divided into seven groups ( n = 5): (1) the GC Tooth Mousse (GCTM) group, (2) the MI Paste Plus (MIPP) group, (3) the DL group, (4) the FV group, (5) the DL + GCTM group, (6) the DL + MIPP group, and (7) the DL + FV group. The samples were then stored in artificial saliva for 1 h, immersed in demineralizing solution for 3 h, and in remineralizing solution for 21 h, repeated over 12 days. Finally, the samples remained in the remineralizing solution for an additional 2 days. The final microhardness was measured on day 14. Mean and standard deviation values summarized the data, with paired t -tests and analysis of covariance used to compare the groups’ microhardness before and after treatment. Data were analyzed using SPSS version 22, with a significance level set at < 0.05. Results: The mean microhardness of all teeth was significantly changed after the intervention ( P < 0.05). The FV (11.09%) and FV + DL (9.89%) groups had a minimum reduction in microhardness, while the GCTM group (38.2%) showed a maximum reduction. DL irradiation before using remineralizing agents increased microhardness in the GCTM + DL and FV + DL groups. However, a decrease in the microhardness of the MIPP + DL group was observed after DL irradiation. No significant difference was observed in the mean microhardness of the DL + GCTM, DL + MIPP, and DL + FV groups compared to the GCTM, MIPP, and FV groups, respectively. Conclusion: Using DL along with FV or GCTM can have a synergic effect on the amount of microhardness. Although this effect was not observed in the DL + MIPP group, FV has a positive effect on tooth microhardness.