Effect of Er,Cr:YSGG laser and CPP-ACP on the prevention of enamel demineralization: In vitro study

Objectives: This study was conducted to compare the effect of Er,Cr:YSGG laser, Casein Phosphopeptide Amorphous Calcium Phosphate (CPP-ACP), and the combined effect of their use on the prevention of enamel demineralization in a sample of extracted premolars.Firstly, using stereomicroscope to assess the severity of the White Spot Lesions (WSLs) visually and secondly, using polarized light microscope to assess the lesions depth. Materials and Methods: Eighty sound extracted premolar teeth were randomly allocated to four equal groups (n=20). Group I: Control group received none of the preventive treatments. Group II: CPP-ACP topical application. Group III: Er,Cr:YSGG laser irradiation. Group IV: Er,Cr:YSGG laser irradiation followed by CPP-ACP application. Specimens were subjected to thermocycling and brushing challenge protocols equivalent to 1 year in oral environment. Then, all teeth were subjected to acid challenge. Each tooth was examined visually and photographed using stereomicroscope to assess the severity of the WSL. The teeth were then sectioned longitudinally and examined under polarized light microscope and the depth of the lesions were measured and compared between the four groups. Results: The combined use of laser and CPP-ACP (Group IV) resulted in the formation of the least severe WSLs and the least lesions depth with a statistically significant difference between group IV and the other three groups.Group IV resulted in 92.5% less lesion depth when compared to the control group. CPP-ACP alone and laser alone also showed a significant difference in the severity of WSLs and lesion depth when compared to the control group, however; no significant difference was found between them. Conclusions: The combined use of Er,Cr:YSGG laser and CPP-ACP showed the best prevention against the development of WSLs regarding the severity and depth. The use of CPP-ACP alone or laser alone also resulted in a significant reduction in lesion depth and severity but was significantly less than their combined use. No significant difference was found between the CPP-ACP alone and laser alone groups.