Shear Bond Strength of Denture Repair with Autopolymerizing Acrylic Resin Influenced by Three Surface Treatments

The repaired denture base material fractures at the interface of base and repair material. This study evaluated the effect of different chemical treatment of the surfaces on the shear bond strength of conventional heat-cured resin repaired with autopolymerized acrylic resin. The specimens were divided into four groups, 30 specimens each according to surface treatment by chemical etchants Group 1 served as control and had no surface treatment. The remaining 3 experimental groups, the specimens were in acetone (Group 2) for 30 seconds, in methylene chloride (Group 3) for 30 seconds and monomer methyl methacrylate (Group 4) for 180 seconds. Autopolymerizing acrylic resin was placed on the treated surface using a Teflon ring. The shear bond strength (MPa) of specimens was measured after 24 hours of storage in distilled water at 37oC. One way analysis of variance and Tukey HSD tests were performed to determine significant differences (∞=.05). The three chemical etchants increased the shear bond strength compared to the control (p<.001). Methyl methacrylate monomer showed the highest shear bond strength compared to methylene chloride and acetone. Methylene and acetone showed no significant differences in shear bond strength.