Effect of Er,Cr:YSGG laser parameters on shear bond strength and microstructure of dentine

Photomed Laser Surg. 2009 Jun;27(3):481-6. doi: 10.1089/pho.2008.2282.


Objective: The objective of this study was to investigate the effect of different Er,Cr:YSGG laser parameters on the morphology of irradiated dentine and the shear bond strength between resin composites and irradiated dentine.

Materials and methods: Dentine specimens prepared from extracted human third molars were randomly assigned to six groups, including one receiving phosphoric acid etching, and five others with different laser parameters: 5 W for 30 sec, 2.5 W for 30 sec, 2.5 W for 60 sec, 1.5 W for 30 sec, and 1.5 W for 100 sec. Surface morphology was examined using a scanning electron microscope (SEM). Average roughness (Ra) was determined with a profilometer. Bonding of resin composites to the dentine specimens was tested in shear mode.

Results: The dentine surfaces irradiated by the Er,Cr:YSGG laser showed a scaly and rugged appearance and open dentinal tubules without smear layer production. The 5-W-irradiated group had the highest roughness value (p < 0.05). One-way ANOVA revealed that the shear bond strength of resin composites to the laser-irradiated dentine ranged from 12.35-15.61 MPa, and was not significantly (p > 0.05) different from the bond strength seen in the acid-etched dentine of 19.06 MPa. However, the surface roughness of the laser-irradiated dentine was significantly (p < 0.05) higher than that of the acid-etched dentine.

Conclusions: The 5-W power setting may be suitable for dental restoration applications in terms of shear bond strength and activation area.

MeSH terms

  • Acid Etching, Dental
  • Analysis of Variance
  • Composite Resins / chemistry*
  • Dental Bonding
  • Dental Cavity Preparation / instrumentation
  • Dental Cavity Preparation / methods
  • Dentin / radiation effects*
  • Dentin / ultrastructure*
  • Dentin-Bonding Agents / chemistry
  • Humans
  • Lasers*
  • Materials Testing
  • Microscopy, Electron, Scanning
  • Molar
  • Smear Layer
  • Stress, Mechanical
  • Tensile Strength


  • Composite Resins
  • Dentin-Bonding Agents