This study aimed at investigating if CO2 laser irradiation (λ =10.6μm - 11.3 J/cm2) combined with fluoridated products,
enhances the CaF2 formation on enamel surface and inhibits lesion progression of demineralized primary enamel. Thus,
135 demineralized primary enamel specimens (DES) were allocated to 9 groups (n=15) as follows: 1- DES only, 2- DES
+ pH cycling (control), 3- 1.23% acidulated phosphate fluoride gel (APF), 4- 1.23% fluoride foam (FF), 5- 5% fluoride
varnish (FV), 6- CO2 Laser (L), 7 - Laser during APF application, 8-Laser during FF application and 9-Laser during FV
application. Except for the demineralized enamel group, all specimens were submitted to a 7 day pH cycling regime. The
knoop hardness number (KHN) was determined by cross-sectional microhardness analysis. After treatments application,
three specimens of each group had their surface examined for CaF2 formation by scanning electron microscopy (SEM).
The data was analyzed by ANOVA and Student's t-test (α= 0.05). Enamel mineral loss (ΔS) for groups 1 to 9 were
99b),(8,723.45±1,167.14b),(9,003.17±796.90b),(8.229,03±961.25b),(9,023.32±1,1069b). The results showed statistically
significant difference between control and all treatments groups (p<0.05). However there was no difference among them
(p>0.05). SEM observations showed evidences of melting, fusion and calcium fluoride formation on enamel surface. In
conclusion, laser irradiation alone or combined with fluoridated products inhibited lesion progression of demineralized
primary enamel surface. However, no synergistic effect was observed when CO2 laser irradiation and fluoridated
products application were combined.