title: Scanning electron microscopic and energy dispersive spectrometric investigations on the effect of XeCl excimer laser on human dentin with smear layer.
abstract: The purpose of this study was to study the effect of XeCl excimer laser on smear layer covered dentine of extracted human teeth. Twenty-four freshly extracted human molar teeth were collected and randomly divided into one control group and three experimental groups of six teeth each (groups A-D). The teeth in the experimental groups were irradiated with XeCl 308-nm excimer laser at a fluence of 0.4 J cm-2 and a constant pulse repetition rate of 25 Hz. Group A was used as the control, while groups B, C and D were irradiated at different exposure times of 3, 5 and 7 s, respectively. Subsequently these teeth specimens were subjected to scanning electron microscopic (SEM) examination and energy dispersive X-ray (EDX) spectrometric analysis. The SEM examination revealed melting of the smear layer covered dentin to conceal the underlying dentinal tubules. At a longer exposure time (7 s), dentin melted to form large grains and this resulted in non-uniform closure of underlying dentinal tubules. Under the conditions of this study, it is concluded that the pulsed XeCl 308-nm excimer laser at a fluence of 0.4 J cm-2, with an exposure time of 5 s uniformly occluded exposed smear layer covered dentine with no conspicuous variation in chemical structure.
authors.affiliation: Department of Conservative Dentistry, Madras Dental College, India. arpradeeep@vsnl.com
authors.forename: A R Pradeep
authors.initials: AR
authors.lastname: Kumar
authors.forename: C V Subba
authors.initials: CV
authors.lastname: Rao
authors.forename: A
authors.initials: A
authors.lastname: Parameswaran
authors.forename: A
authors.initials: A
authors.lastname: Kishen
authors.forename: C S
authors.initials: CS
authors.lastname: Lim
mesh_terms: D002118:Calcium / Q000032:analysis; D002713:Chlorine; D003804:Dentin / Q000737:chemistry / Q000528:radiation effects* / Q000648:ultrastructure; D006801:Humans; D053685:Laser Therapy; D008274:Magnesium / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D008963:Molar; D010758:Phosphorus / Q000032:analysis; D013052:Spectrometry, X-Ray Emission; D014978:Xenon
chemical_list: D010758:Phosphorus; D014978:Xenon; D002713:Chlorine; D008274:Magnesium; D002118:Calcium