Combined effect of Er,Cr:YSGG laser and casein phosphopeptide amorphous calcium phosphate on the prevention of enamel demineralization

To compare the effect of use of laser, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), and their combination on prevention of enamel demineralization using polarized light microscopy to assess lesion depth. Eighty premolars were randomly allocated to four equal groups (n = 20): Group I: Control group, no preventive measures. Group II: CPP-ACP. Group III: Er,Cr:YSGG laser. Group IV: Er,Cr:YSGG laser followed by CPP-ACP. Specimens were subjected to thermocycling and brushing protocols equivalent to 1 year intraorally. Then, all teeth were subjected to acid challenge. Teeth were then sectioned longitudinally and examined under a polarized light microscope and lesion depth was measured. Group IV resulted in the least lesion depth with a significant difference between it and all other groups. CPP-ACP alone and laser alone also showed a significant difference in white spot lesion (WSL) depth compared to the control group; however, no significant difference was found between them. The combined use of laser and CPP-ACP showed the best prevention against WSL development. The use of CPP-ACP or laser alone also resulted in a significant reduction in lesion depth but was significantly less than their combined use, with no significant difference between them.