To investigate and compare the effect of self-assembling peptide SAP (P_11-4), casein phosphopeptide-amorphous calcium phosphate fluoride paste (CPP-ACPF), and fluoride varnish (FV) on preventing enamel demineralization around orthodontic brackets.

Orthodontic brackets were bonded to the buccal surfaces of 80 freshly extracted human maxillary premolars. Teeth were randomly assigned to four groups (n=20) according to the remineralizing agent used as follows: SAP (P_11-4) group (Curodont™ Protect/Credentis), CPP-ACPF group (MI Paste Plus®/Recaldent™), fluoride varnish group (Profluoride varnish®/VOCO), and control group. All products were applied according to the manufacturer's instructions. Specimens were cycled in daily refreshed demineralizing and remineralizing solutions for 8h and 16h, respectively, for 28 days. The calcium/phosphorus ratio (Ca/P) and surface microhardness (SMH) were evaluated at baseline and at two and four weeks. Two-way ANOVA (analysis of variance), one-way ANOVA and repeated measures ANOVA were used for statistical analysis.

Two-way ANOVA demonstrated significant differences between remineralizing agents and time points. After 4 weeks, the SAP (P_11-4) group had had significantly higher Ca/P ratio and SMH (1.68±0.11 and 346.47±55.38) compared to other groups, followed by CPP-ACPF (1.52±0.19 and 283.53±64.75), FV (1.37±0.14 and 262.80±82.98), and the control group (1.31±0.10 and 213.00±41.95). Significantly higher Ca/P ratio and SMH were observed at 2 weeks in the control group (1.44±0.10 and 269.63±57.37) and FV group (1.52±0.09 and 321.17±55.24) compared to 4 weeks. No significant differences were found regarding Ca/P ratio and SMH at 2 weeks in the CPP-ACPF (1.55±0.15 and 295.14±53.88) and SAP P_11-4 groups (1.64±0.10 and 320.18±58.04) compared to 4 weeks.

SAP (P_11-4) had the greatest remineralizing efficacy compared to FV and CPP-ACPF. Moreover, extended period of time improved the preventive efficacy of SAP (P_11-4) compared to the other regimens.