Comparison of enamel remineralization potential after application of titanium tetra fluoride and carbon dioxide laser

抄録

Background and Aims: The aim was comparison of enamel remineralization after application of APF, TiF4 and CO2 laser alone or in combination.
Materials and Methods: Enamel blocks were prepared from human third molars. The initial surface hardness was determined by Vicker's hardness tester. The samples underwent a demineralization regimen for 7 days to produce artificial initial caries. The hardness of enamel blocks with white spot lesions was measured, and the samples which had the mean hardness change of 65-90%, were selected, and randomly divided into 5 groups (N=15): G1: control; G2: APF 1.23%; G3: TiF4 4%; G4: TiF4 4% followed by CO2 laser (10.6 μm wavelength, 1 W peak power, 10 ms pulse duration, 500 ms repeat time, 0.2 mm beam spot size, 2 cm distance); G5: CO2 laser (same parameters) followed by TiF4 4%. Surface hardness recovery was measured after the treatments. Three samples in each group were observed under scanning electron microscope at x1,000 magnification. Data were analyzed by repeated measure ANOVA and Bonferrouni tests. Significance level was set at 0.05..
Results: G2, G3, G4 indicated significant differences with control and G5 (p<0.05). Surface hardness in G5 was not significantly different from control (p=0.7) in enamel hardness test. There was not a significant difference between G2 & G3, G2 & G4, and G3 & G4 (p=1). The SEM results indicated globules of calcium fluoride on the surface in G2, and a smooth glaze-like surface layer in G3 and G4. In G5, some micro-cracks without any glaze-like layer were observed.
Conclusions: APF, TiF4 and TiF4 before CO2 laser irradiation significantly increased the microhardness of initially demineralized enamel surfaces. CO2 laser irradiation before TiF4 application could not remineralize the white-spot lesions.