title: Effects of laser irradiation on machined and anodized titanium disks.
abstract: OBJECTIVE
  Although the laser has become one of the most commonly used tools for implant dentistry, research is lacking on whether or not the laser causes any changes on the surface of titanium (Ti) implants. The present study analyzed the morphology, composition, crystal structure, and surface roughness changes of machined and anodized Ti surfaces, irradiated with erbium chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG), erbium-doped yttrium-aluminum-garnet (Er:YAG), and carbon dioxide (CO2) lasers.
  
  
  METHODS
  Seventy-two Ti disks were fabricated by machining commercially pure Ti (grade 3); 36 of them were anodized at 300 V. The disks were irradiated with Er,Cr:YSGG, Er:YAG, and CO2 lasers at five different powers (1, 2, 3, 4, and 5 W). The irradiated disks were examined with scanning electron microscopy, electron probe microanalysis, x-ray diffractometry, and optical interferometry.
  
  
  RESULTS
  Surface changes were observed on both types of Ti surfaces irradiated with the Er,Cr:YSGG laser when more than 3 W of power were applied. Surface changes were observed on both types of Ti surfaces when irradiated with the Er:YAG laser with more than 2 W of power. No change was observed when the disks were irradiated with the CO2 laser. The proportion of oxide in the machined Ti disk increased after the application of the Er,Cr:YSGG or Er:YAG laser. In the anodized Ti disk, the anatase peak intensity decreased and the rutile peak intensity increased after laser irradiation. The irradiated Ti disks were significantly rougher than the nonirradiated Ti disks.
  
  
  CONCLUSIONS
  The Er:YAG and Er,Cr:YSGG laser resulted in surface changes on the Ti disks according to the power output. The CO2 laser did not affect the surface of the Ti disks, irrespective of the power output.
authors.affiliation: Department of Prosthodontics, School of Dentistry, Seoul National University, Seoul, South Korea.
authors.forename: Ji-Hye
authors.initials: JH
authors.lastname: Park
authors.forename: Seong-Joo
authors.initials: SJ
authors.lastname: Heo
authors.forename: Jai-Young
authors.initials: JY
authors.lastname: Koak
authors.forename: Seong-Kyun
authors.initials: SK
authors.lastname: Kim
authors.forename: Chong-Hyun
authors.initials: CH
authors.lastname: Han
authors.forename: Joo-Hee
authors.initials: JH
authors.lastname: Lee
mesh_terms: D002118:Calcium / Q000032:analysis; D002244:Carbon / Q000032:analysis; D003461:Crystallography; D003764:Dental Materials / Q000737:chemistry / Q000528:radiation effects*; D055664:Electrochemical Techniques; D004577:Electron Probe Microanalysis; D006801:Humans; D007368:Interferometry; D054020:Lasers, Gas; D053844:Lasers, Solid-State; D008027:Light; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009584:Nitrogen / Q000032:analysis; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis; D010758:Phosphorus / Q000032:analysis; D011829:Radiation Dosage; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects*; D014961:X-Ray Diffraction
chemical_list: D003764:Dental Materials; C009495:titanium dioxide; D010758:Phosphorus; D002244:Carbon; D014025:Titanium; D009584:Nitrogen; D010100:Oxygen; D002118:Calcium