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Three‐dimensional topographic scanning electron microscope and Raman spectroscopic analyses of the irradiation effect on teeth by Nd:YAG, Er: YAG, and CO 2 lasers
Author(s) -
Yamada Magda K.,
Uo Motohiro,
Ohkawa Shoji,
Akasaka Tsukasa,
Watari Fumio
Publication year - 2004
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.30063
Subject(s) - dentin , laser , irradiation , materials science , raman spectroscopy , scanning electron microscope , enamel paint , er:yag laser , nd:yag laser , fluence , surface roughness , optics , composite material , physics , nuclear physics
A three‐dimensional analyzer installed in a scanning electron microscope was used to evaluate the morphology and surface roughness using noncontact profilometry. Observations were carried out on the enamel and dentin surface irradiated by three different lasers: Nd:YAG (wavelength 1.06 μm), Er:YAG (2.94 μm), and CO 2 (10.6 μm). Spectroscopic analysis was done by Raman spectroscopy for nonirradiated and laser‐irradiated surfaces. The lasers were applied perpendicularly to vertically sectioned and polished human extracted caries‐free molars. The tooth was sectioned at each cavity for cross‐section analysis after laser irradiation. Irradiation by Nd:YAG and CO 2 lasers of the enamel surface showed an opaque white color, different from dentin where the surface turned black. The Er:YAG laser induced no changes in color of the dentin. Numerous cracks associated with thermal stress were observed in the CO 2 laser‐irradiated dentin. Noncontact surface profile analysis of Er:YAG laser‐irradiated enamel and dentin showed the deepest cavities, and direct cross‐sectional observations of them showed similar cavity outlines. The CO 2 laser‐irradiated dentin had the least surface roughness. Raman spectroscopic analysis showed that fluorescence from the laser‐irradiated tooth was generally greater than from nonirradiated teeth. Bands in dentin attributed to organic collagen matrix were lost after Nd:YAG and CO 2 laser irradiation, and a broad peak due to amorphous carbon appeared. The Er:YAG laser‐irradiated dentin showed no sign of a carbon band and had more suitable results for dental ablation. Noncontact surface profile analysis was effective to evaluate the structural change in the tooth in the microarea of study after laser irradiation. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 7–15, 2004