title: Effects of carbon dioxide, Nd:YAG and carbon dioxide-Nd:YAG combination lasers at high energy densities on synthetic hydroxyaptite.
abstract: The aim of this study was to determine the crystalline structure and chemical alterations of synthetic hydroxyapatite after irradiation with either CO2, Nd:YAG or CO2-Nd:YAG combination lasers at high energy densities of 500-3,230 J.cm2. Further, dissolution kinetics of the lased material were analysed and compared with those of unlased apatite. Electron microscopy showed that the lased material consisted of two kinds of crystals. From the micrographs their diameters varied from 600 to 1,200 A and from 3,000 to 6,000 A, respectively. The larger crystals showed 6.9-Angström periodic lattice fringes in the transmission electron microscope. alpha-Tricalcium phosphate (TCP) was identified by X-ray diffraction. Selective-area electron diffraction identified the large crystals to consist of tricalcium phosphate while the smaller crystals were probably hydroxyapatite. Assays of dissolution kinetics showed that at these high energy densities lased material dissolved more rapidly than unlased synthetic hydroxyapatite due to the higher solubility of TCP.
authors.affiliation: Department of Cariology, University of Helsinki, Finland.
authors.forename: J H
authors.initials: JH
authors.lastname: Meurman
authors.forename: J C
authors.initials: JC
authors.lastname: Voegel
authors.forename: R
authors.initials: R
authors.lastname: Rauhamaa-Mäkinen
authors.forename: P
authors.initials: P
authors.lastname: Gasser
authors.forename: J M
authors.initials: JM
authors.lastname: Thomann
authors.forename: J
authors.initials: J
authors.lastname: Hemmerle
authors.forename: M
authors.initials: M
authors.lastname: Luomanen
authors.forename: I
authors.initials: I
authors.lastname: Paunio
authors.forename: R M
authors.initials: RM
authors.lastname: Frank
mesh_terms: D000538:Aluminum Silicates; D002130:Calcium Phosphates / Q000737:chemistry / Q000528:radiation effects; D002245:Carbon Dioxide; D003461:Crystallography; D017886:Durapatite; D004577:Electron Probe Microanalysis; D006358:Hot Temperature; D006882:Hydroxyapatites / Q000737:chemistry* / Q000528:radiation effects*; D007700:Kinetics; D007834:Lasers; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009354:Neodymium; D012995:Solubility; D013499:Surface Properties; D014961:X-Ray Diffraction; D015019:Yttrium
chemical_list: D000538:Aluminum Silicates; D002130:Calcium Phosphates; D006882:Hydroxyapatites; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D002245:Carbon Dioxide; D009354:Neodymium; D015019:Yttrium; C485838:calcium phosphate, monobasic, anhydrous; D017886:Durapatite; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous