Comparative Efficacy of CO2 Laser-Activated CPP-ACP, Nano-Hydroxyapatite, and Self-Assembling Peptide P11-4 on Enamel Remineralization and Pit and Fissure Sealant Adhesion in Demineralized Primary Dentition.

AIMS: To compare the effects of different remineralizing agents, namely nano-hydroxyapatite (Nano-HA), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), carbon dioxide (CO2) laser-activated CPP-ACP, and Curodont™ Repair, on the resin tag length (RTL), shear bond strength (SBS), and calcium/phosphate (Ca/P) ratio of artificially demineralized primary molar enamel. MATERIAL AND METHODS: A total of 130 caries-free primary molars were subjected to standardized chemical demineralization, following occlusal surface flattening with a flat-end diamond bur. The specimens were randomly distributed into five groups according to the type of remineralization technique (n = 26): Group 1 (Control), Group 2 (CPP-ACP), Group 3 (CPP-ACP + CO2 laser), Group 4 (0.15% Nano-HA), and Group 5 (Curodont Repair). After pretreatment, eight samples per group were assessed for Ca/P ratio using energy dispersive spectroscopy. Pit and fissure sealants (PFSs) were applied to all the remaining specimens (n = 18). RTL was assessed in eight specimens per group using scanning electron microscopy (SEM), whereas SBS was measured in the remaining 10 specimens using a universal testing machine. Failure mode analysis was conducted using stereomicroscopic evaluation. Statistical comparisons were performed using analysis of variance and Tukey's post hoc test (p < 0.05). RESULTS: Group 4 (0.15% Nano-HA) achieved the highest mean Ca/P ratio (2.27 ± 0.18), significantly superior to all other groups. The longest RTL (54.22 ± 2.45 μm) and highest SBS (10.12 ± 0.21 MPa) were recorded in the Nano-HA group. Conversely, Curodont Repair produced the shortest RTL (23.21 ± 1.43 μm) and weakest SBS (7.89 ± 0.14 MPa) among all tested groups. CONCLUSIONS: Nano-HA demonstrated the most favorable influence on RTL, SBS, and Ca/P ratio before PFS placement on demineralized primary molar enamel, followed by CPP-ACP with or without CO2 laser adjunction. Curodont Repair improved the Ca/P ratio but failed to enhance sealant bonding.