Effect of Argon Laser Curing on the Shear Bond Strength of Composite Resin Restorative Material

Aim: The aim of this in vitro study was to analyze the shear bond strength of composite resin using two different curing light sources: halogen light (control group) for 20 or 40s, and Argon laser (test group) for 10 or 15s.

Study Design: This study was carried in the Department of Dental Biomaterials, Faculty of Dentistry and Ophalmolgy Hospital, Mansura University between January 2011 and August 2012.

Methodology: Sixty freshly extracted human molars were prepared to receive composite resin samples in four groups "n=15". The teeth were centrally horizontally mounted in plastic molds with cold cure acrylic resin. Flat occlusal surfaces were prepared and smoothed. One-step self-etching dental adhesive (Xeno®111) was applied to the dentine surface and cured. Composite resin (Spectrum universal composite) was inserted into standardized Perspex mold and polymerized with a halogen light and an argon laser curing units. Specimens were stored in deionized water at 37oC for 48 hours. The specimens were stressed under shear force at a crosshead speed of 0.5 mm/min using Lloyd testing machine. The shear bond strength was calculated to the four groups and statistical analysis performed (One-way ANOVA and LSD tests) at the level of significance at p<0.05.

Results: LSD tests indicated that there was significantly higher shear bond strength for the composite cured with argon laser compared with the halogen light curing method. There was no statistical significant difference between curing times of the same light source.

Conclusions: The argon laser is a promising source for optimal initiation of polymerization of composite resins. The use of argon laser has been suggested as a new alternative for polymerization of restorative materials. The shear bond strength of composite resin cured with argon laser was superior to that was cured with halogen light even with short curing times.