Influence of CO2 Laser and Fluoride in Deciduous Caries Enamel

Objectives: The CO₂ laser irradiation and the employment of fluoride compounds may contribute to the deciduous tooth enamel becoming more resistant to acid challenges. Thus, this study aims evaluating in vitro the effect of CO₂ laser irradiation and fluoride compounds in the control of the progression of carious lesions on deciduous enamel by subsurface microhardness analysis.

Methods: A total of 40 deciduous canines were used, of which fragments were obtained (3x3x2mm). These fragments were submitted to an initial cariogenic challenge that consisted of immersion on demineralizing solution for 3 hours and remineralizing solution for 21 hours, for 5 days. The fragments were randomly assigned into 4 groups (n = 10) according to the superficial treatment: CO₂ - CO₂ laser (10.6 µm), VF – 5 fluoride varnish, FFA – 1.23% acidulated phosphate fluoride and ST - no treatment (control). The CO©ü laser was applied in ultra-pulse mode with 0.5 W power and 0.04 J/cm²power density. In the groups treated with fluoride, application was performed from 0.1 g for one minute. Then, the cariogenic challenge after the superficial treatment was conducted for five days, following the protocol described previously. The subsurface microhardness Knoop (KHN) was measured at 30μm from the edge. The data obtained were subjected to analysis of variance (ANOVA) and Duncan test with significance of 5%.

Results: It was found that the subsurface microhardness on the enamel of deciduous teeth obtained after irradiation with CO₂ laser was similar to that obtained after the application of FFA but statistically different from the VF and ST groups (p ≤ 0.05) that received the lowest average.

Conclusions: It was concluded that the CO₂ laser can be an additional resource in the control of the progression of carious lesions on enamel of deciduous teeth.