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Scanning Electron Microscopic Study of the Effects of Er:YAG Laser on Root Cementum
Author(s) -
Fujii Takeo,
Baehni Pierre C.,
Kawai Osamu,
Kawakami Tomofumi,
Matsuda Koichi,
Kowashi Yusuke
Publication year - 1998
Publication title -
journal of periodontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.036
H-Index - 156
eISSN - 1943-3670
pISSN - 0022-3492
DOI - 10.1902/jop.1998.69.11.1283
Subject(s) - cementum , scanning electron microscope , materials science , laser , er:yag laser , irradiation , dental cementum , smear layer , composite material , dentin , optics , physics , nuclear physics
U se of E r :YAG laser has been proposed for the removal of microbial deposits and calculus present on teeth affected by periodontal disease. However, the influence of Er:YAG laser irradiation on root surfaces has not yet been fully investigated. The aim of the present study was to evaluate the effects of Er:YAG laser irradiation on root cementum by scanning electron microscopy (SEM). Specimens were obtained from extracted human periodontally‐diseased teeth using a water‐cooled high‐speed bur. An Er:YAG laser beam was then applied at various powers ranging from 25 to 100 mJ/pulse/sec. The laser irradiation was performed under water irrigation, with the tip held perpendicular to the root surface in the contact mode. Following laser exposure, specimens were fixed, dehydrated, and dried at critical‐point in liquid CO 2 . After mounting on SEM plates and sputter‐coating with gold, the cementum surface was examined by SEM. Observations of the root surface showed a relatively flat surface in control specimens. In Er: YAG exposed specimens, the laser beam created a circular, notchededge, crater‐like defect on the root. The bottom of the lesion showed an irregular and sharp‐pointed surface. Subsequently, the specimens were fractured with a sharp scalpel perpendicularly to the surface. SEM observations of these specimens showed a 15 pm layer of damaged tissue within the laser‐irradiated cementum. The tissue presented an amorphous appearance and the Sharpey's and matrix fiber bundles were not clearly distinguishable. These observations indicate that cementum tissue could be damaged by Er:YAG laser irradiation. J Periodontol 1998;69:1283–1290 .