Background and Aim: With the increase of laser application in different fields of dentistry, further research is required to evaluate it's efficiency in dental therapy. This study evaluated the effect of Er,Cr:YSGG laser conditioning of enamel on micro shear bond strength of composite ressin to human enamel following two different tooth preparation tools (Diamond Disk Versus Er, Cr: YSGG laser)
Materials & Methods: In this invitro study, 125 human third molars were randomly assigned into 5 groups. Buccal and lingual enamel slices were prepared as below: A) laser-ablated without etching, B) laser-ablated and laser-etched, C) laser-ablated and acid-etched, D) cut by diamond disk and laser-etched and E) cut by diamond disk and acid-etched. Tubs of Z100 composite resin (3M, Dental Product/ USA) were bonded to conditioned enamel surfaces after applying two layers of Single Bond (3M ESPE, Dental product/ USA) Shear bond strength was measured by Micro-Tensile tester (Bisco Inc/USA) at a cross-head speed of 0.5 mm/min. Data were analyzed by one-way ANOVA,and Tukey tests.
Results: Mean shear bond strengths in groops were : A= 23.14 ± 6.53 MPa,B= 23.77 ± 5.56 MPa,C= 23.51 ± 4.89 MPa,D= 19.30 ± 5.56 MPa and E= 28.99 ± 6.40 MPa ,respectively.The differences between (E,A),(E,B),(D,B),(C,D) and (D,E) were significant (P<0.05).
Conclusion: Micro shear bond strength of groups prepared by diamond disk and acid-etched were higher than groups prepared and etched by Er,Cr:YSGG laser.Therefore, re-etching with acid phosphoric is necessary if the laser used for tooth preparation or etching.
J Dent Sch 2010 28(1): 1