Physical Effects On The Interactions Of Co2 Laser On The Teeth
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Date
2010
Authors
Ahmad, Alwani Liyana
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Recent studies have shown that CO2 lasers can successfully be used at low-power densities to fuse enamel, dentin, and apatite. In this study, forty nine samples of different types of extracted human teeth were irradiated under low power continuous wave CO2 laser. The mass, density, and thickness of each type of teeth were recorded before and after irradiation. Density and thickness of the sample was measured using gas pycnometer and gamma spectroscopy with Americium-241 source, respectively. Chemical compounds of teeth were determined using Fourier Transform Infrared Spectroscopy (FTIR), diameter of penetration with biological microscope, and the penetration depth was calculated by differentiation of thickness before and after irradiation. Results show that the diameter of penetration increased with laser power because fusing and melting of enamel crystals after the irradiation, affected the enamel surface. As the laser power is increased, the depth of laser penetration gradually increased but nonuniform. When laser power above 9 W is used, ash was formed on the surface of the teeth and this further reduced the laser penetration. Laser power above 18 W, however, will damage the teeth. The mass of teeth after irradiation is less than before irradiation due to the fact that combustion occurred when the teeth were irradiated with CO2 laser and caused the crystalline compounds melting at high temperature. The results obtained, however, indicate that the densities of some teeth increased after irradiation. This situation occurs due to other factors such as temperature since density
depends on temperature and the volume of a substance can change with temperature and also because the present of water. The main chemical compounds of teeth identified after irradiation showed that higher laser power has a higher percentage of reflectance because the temperature dependence of the rate constant, and therefore, rate of chemical reaction, which can be explained using Arrhenius equation.
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Keywords
CO2 lasers can successfully be used at low-power densities , to fuse enamel, dentin, and apatite