Effects of Fractional Carbon Dioxide Laser and CPP-ACP Paste on Remineralization and Discoloration of Enamel White Spot Lesions

Background and Aim:The prevalence of enamel demineralization around orthodontic brackets is high.This study investigated the effects of CO 2 laser and casein phosphopeptide amorphous calcium phosphate (CPP-ACP) on enamel white spot lesions (WSLs). Materials and Methods:In this in vitro study, 60 human premolars were stored in a demineralizing solution for 12 weeks to induce WSLs, and divided into four groups (n=15) of no surface treatment (control), CPP-ACP paste application for 4 minutes/day for one week, and CO 2 laser (10 mJ, 200 Hz, 10 s) with/without CPP-ACP paste.The teeth were then immersed in artificial saliva for 90 days while being subjected to daily fluoride mouthwash and weekly brushing.Tooth color was measured at baseline, after demineralization, after the interventions, and after 90 days of storage.The Vickers microhardness of the teeth was measured at the enamel surface and 30-, 60-, and 90-µm depths.Data were analyzed by one-way and repeated measures ANOVA and Friedman test.Results: No significant difference was found among the four groups concerning color change, and all groups had clinically detectable discoloration after remineralization.Laser irradiation through CPP-ACP paste caused a significant increase in microhardness compared to CPP-ACP alone and the control group (P<0.05).Microhardness at 30-, 60and 90-µm depths was also significantly greater in laser/CPP-ACP compared to other groups (P=0.0001).Conclusion: Application of fractional CO 2 laser with/without CPP-ACP paste was not effective in improving the color of WSLs.However, application of CO 2 laser through CPP-ACP may be suggested for rehardening of demineralized enamel.