2016 Volume 59 Issue 6 Pages 479-488
Purpose: The purpose of this study was to investigate in detail the morphological changes of enamel irradiated with CO2 laser with different wavelengths (λ: 10.6 and 9.3 μm).
Materials and Methods: One of the specimens prepared from freshly extracted bovine teeth was irradiated by CO2 laser with 9.3 μm wavelength (9.3-laser, experimental apparatus by Takara Belmont Corp., Japan) using three energy densities (119.0 J/cm2, 158.7 J/cm2, 238.1 J/cm2) for 0.1 sec. The other specimen was irradiated by CO2 laser with 10.6 μm wavelength (10.6-laser, Bel-Laser, Takara Belmont Corp., Japan) in the same way. The morphological changes of the 9.3- and 10.6-lased enamels were examined using a scanning electron microscope (SEM). Then, the three-dimensional shapes of the 9.3- and 10.6-lased enamels were observed and analyzed using a laser scanning microscope.
Results: Under the SEM observation, the morphological changes produced in the 9.3-lased enamel consisted of stratified morphologies like fish scales, hyaline morphologies, craters and cracks. The morphological changes were the same as those in the 10.6-lased enamel. However, the degree of morphological changes was different between the 9.3 μm-lased and 10.6 μm-lased enamels: the 9.3-lased enamel showed greater changes compared to the 10.6-lased enamel. Furthermore, cracks appeared within the irradiated area of the 9.3-lased enamel, but outside of the irradiated area of the 10.6-lased enamel.
Conclusion: Under these experiment conditions, it was suggested that the 9.3 μm-laser irradiation demonstrated the same characteristic changes as those of 10.6-laser irradiation at the same energy density. However, the degree of morphological changes was more remarkable with the 9.3 μm-laser irradiation.
