Comparative evaluation of remineralization agents in severe enamel hypomineralization using a porcine enamel model

To comparatively evaluate the effects of fluoride varnish, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) varnish, and self-assembling peptide P₁₁-4 on the microhardness and surface morphology of hypomineralized enamel using a porcine model simulating molar incisor hypomineralization (MIH).

Eighteen hypomineralized primary canines and needle teeth (the erupted third incisors of newborn piglets) obtained from three stillborn Yorkshire piglets were included in this in vitro study. Following stereomicroscopic examination, samples were randomly allocated into three groups (n = 6): Group 1: sodium fluoride (NaF) varnish, Group 2: NaF + CPP-ACP varnish, and Group 3: P₁₁-4. Baseline microhardness (T0) was measured using a microhardness tester under a 300 g load for 15 s. Remineralization agents were applied according to manufacturers' instructions. P₁₁-4 application included prior sodium hypochlorite cleaning and phosphoric acid etching. Samples were stored in artificial saliva at 37 °C. Microhardness measurements were repeated at 1 week (T1) and 1 month (T2). One representative sample from each group was analyzed using scanning electron microscopy (SEM). Statistical analysis was performed using two-way repeated measures ANOVA and Bonferroni post hoc tests (p < 0.05).

Microhardness values significantly increased over time in all groups (p < 0.001). Significant differences were observed between all-time points (T0-T1, T0-T2, T1-T2) within each group. At T2, the P₁₁-4 group demonstrated the highest microhardness values, followed by NaF + CPP-ACP and NaF groups (p < 0.05). Intergroup comparisons revealed statistically significant differences, particularly between P₁₁-4 and the other groups at T2. SEM images demonstrated an irregular surface morphology related to mineral deposit accumulation after the application of remineralization agents. Nevertheless, in the P₁₁-4 group, the covering deposits and crack-like lines appeared less scattered and more integrated than in the other treatment groups.

All remineralization agents improved enamel microhardness; however, P₁₁-4 demonstrated superior efficacy compared to NaF + CPP-ACP and NaF varnish. Porcine enamel appears to be a reliable and biologically relevant model for simulating MIH-affected enamel in vitro.