Purpose: To evaluate and compare the shear bond strength between a commercially available self-cured silicon-based liner and polymethyl methacrylate (PMMA) denture base resin with different surface treatments.

Materials and Methods: A soft denture liner Ufi-Gel P (silicone-based liner) and polymethyl methacrylate denture base resin (Rodex) were chosen for this study. A total of 50 samples were made, the samples were divided into five groups, containing 10 samples each. Group I: Consisted of an untreated surface of polymethyl methacrylate which acted as the control. Group II: The polymethyl methacrylate surface was treated with Acetone. Group III: The surface of polymethyl methacrylate surface was treated with laser Er:YAG with three different pulses duration. The shear bond strength was examined by Instron Universal Testing Machine at crosshead speed of 40mm/min. T-student test was used to analyze the data (α=0.05).

Results: There was a statistically significantly difference in shear bond strength between laser-treated and untreated specimens (P<0.05). The 300 mJ laser treatment produced the highest mean shear bond strength (P<0.05).

Conclusions: Laser irradiation produced significant surface texture changes of the denture base material and improved the adhesion between denture base and soft lining material. In addition, different pulses duration was found to effectively increase the strength of the bond.