Influence of CO2 Laser Irradiation and CPP-ACP Paste Application on Demineralized Enamel Microhardness

Introduction: It has been suggested that the application of casein phosphopeptide-amorphous calcium phosphate paste (CPP-ACP) and CO2 laser irradiation on enamel could increase the resistance of enamel to caries and acid attacks. The aim of the current study was to compare the influence of CPP-ACP paste application and irradiation of CO2 laser on microhardness of demineralized enamel. Methods: Thirty sound maxillary extracted premolars were selected. The crowns were cut at the cervical line and were split into facial and palatal halves. Specimens were mounted in self-cure acrylic blocks in such way that the enamel surface was exposed to 4×4 mm. After a pH cycling of the specimens, they were randomly divided into 4 groups (n = 15), as follows: CG: Control group, LAS: CO2 laser, CP: CPP-ACP and LASCP: laser combined CPP-ACP treatment. The Vickers microhardness of the specimens was measured (500 g load, 5 seconds, 3 points). Data were analyzed using one-way ANOVA and post hoc Tukey tests (α = 0.05). Results: The lowest mean Vickers microhardness value was observed in CG group (192.57±50.87 kg/mm2) and the highest in LASCP group (361.86±22.22 kg/mm2). There were significant differences between groups (P < 0.001). The pairwise comparison of the groups revealed that there were significant differences between these groups: CG versus LAS, CP, LASCP (P < 0.05) and LASCP versus LAS and CP (P < 0.05). No significant difference between LAS group versus CP group (P > 0.05) was observed. Conclusion: The results of the current study revealed that CO2 laser and CCP-ACP were effective for improvement of enamel hardness value after demineralization. Incorporation of CO2 laser irradiation and CCP-ACP paste application provides additional remineralizing potential for demineralized enamel.