title: An analysis of surface roughness, surface morphology and composite/dentin bond strength of human dentin following the application of the Nd:YAG laser.
abstract: OBJECTIVE
  This study was conducted to investigate the surface effects to dentin following laser "etching" with an Nd:YAG laser, and to determine the shear bond strengths of composite to untreated and laser-treated dentin.
  
  
  METHODS
  Dentin surfaces from freshly extracted permanent molar teeth were subjected to laser treatment with an Nd:YAG laser using different laser pulse rates and power settings. The effect of application of a laser enhancing gel was also investigated. Surface profile analysis of the dentin surfaces was undertaken with a perthometer. The results were analysed by SPSS/PC multiple range test. Specimens were examined using a scanning electron microscope (SEM). The shear bond strengths of laser-treated dentin/composite and untreated dentin/composite by conventional dentin bonding (Gold Standard, Chameleon Dental Products) were also determined. These results were also compared by SPSS/PC multiple range test.
  
  
  RESULTS
  The laser-treated dentin specimens exhibited a qualitatively different surface morphology when compared with untreated dentin. Laser treatment at higher exposures resulted in the formation of microcracks and fissures. Bonding of resin composite to the laser-treated dentin was not significantly different from untreated dentin despite the fact that the surface roughness of laser-treated dentin was significantly higher than untreated dentin (p < 0.05).
  
  
  CONCLUSIONS
  It was concluded from this study that the etched dentin surfaces produced by the Nd:YAG laser operated under the conditions described were not superior to those obtained with conventional dentin bonding.
authors.affiliation: University of Manchester Dental Hospital, UK.
authors.forename: M T
authors.initials: MT
authors.lastname: Ariyaratnam
authors.forename: M A
authors.initials: MA
authors.lastname: Wilson
authors.forename: A S
authors.initials: AS
authors.lastname: Blinkhorn
mesh_terms: D001840:Dental Bonding; D003804:Dentin / Q000528:radiation effects* / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005782:Gels; D006801:Humans; D007834:Lasers; D009354:Neodymium; D018709:Statistics, Nonparametric; D013499:Surface Properties / Q000528:radiation effects
chemical_list: D017220:Dentin-Bonding Agents; D005782:Gels; D009354:Neodymium