Abstract
BACKGROUND: This study aimed to compare the effects of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) in combination with gallic acid (GA) compared to their individual effects on improving the microhardness of artificial enamel lesions at different depths from the surface. MATERIALS AND METHODS: Forty enamel blocks were fabricated, with one-third of each block coated in varnish to establish a protected sound zone. The blocks were submerged in a demineralizing solution for 96 h to create artificial enamel lesions. Subsequently, half of the demineralized region was coated with varnish to create a reference demineralized area. The samples were allocated to four groups, with the remaining exposed portions treated with three experimental pastes (CPP-ACP paste, GA paste, and CPP-ACP + GA paste) and one control paste, representing the remineralized area. Vickers microhardness was assessed at depths of 20, 50, 100, 150, and 200 μm from the enamel surface in each region. Data were analyzed utilizing one-way ANOVA, followed by post hoc LSD tests. Cohen's d effect sizes and 95% confidence intervals (CIs) were also calculated to assess the strength of pairwise comparisons. RESULTS: The CPP-ACP + GA paste exhibited the most significant enhancement in enamel microhardness at depths of 20, 50, and 100 μm with large effect sizes. While both CPP-ACP paste and GA paste significantly enhanced microhardness at 20 and 50 μm depths, they did not considerably impact microhardness at 100 μm depth. CONCLUSION: The combined use of CPP-ACP and GA showed a superior enhancement in the microhardness of artificial enamel lesions compared to the individual application of each agent.