CO2 laser irradiation enhances CaF2 formation and inhibits lesion progression on demineralized dental enamel—in vitro study

This study evaluated if Carbon dioxide (CO 2 ) ( λ 10.6 μm) laser irradiation combined with acidulated phosphate fluoride gel application (APF gel) enhances “CaF 2 ” uptake by demineralized enamel specimens (DES) and inhibits enamel lesion progression. Thus, two studies were conducted and DES were subjected to APF gel combined or not with CO 2 laser irradiation (11.3 or 20.0 J/cm 2 , 0.4 or 0.7 W) performed before, during, or after APF gel application. In study 1, 165 DES were allocated to 11 groups. Fluoride as “CaF 2 like material” formed on enamel was determined in 100 DES ( n = 10/group), and the surface morphologies of 50 specimens were evaluated by scanning electron microscopy (SEM) before and after “CaF 2 ” extraction. In study 2, 165 DES (11 groups, n = 15), subjected to the same treatments as in study 1, were further subjected to a pH-cycling model to simulate a high cariogenic challenge. The progression of demineralization in DES was evaluated by cross-sectional microhardness and polarized light microscopy analyses. Laser at 11.3 J/cm 2 applied during APF gel application increased “CaF 2 ” uptake on enamel surface. Laser irradiation and APF gel alone arrested the lesion progression compared with the control ( p