Bond strength of denture base resins to acrylic teeth

Objectives:The purpose of this study was to evaluate the effect of methyl methacrylate monomer(MMA) on bond strength of denture base resins to acrylic teeth. Methods:Two acrylic teeth Biotone(B) and Trilux(T) were chosen for bonding to three denture base resins: microwave-polymerized Acron MC(A) and heat-polymerized Lucitone 550(L) and QC-20(Q). The specimens were composed of denture base resin cylinders bonded to the acrylic teeth. Each acrylic tooth was embedded in autopolymerizing polymer using an embedding machine. Silicone patterns with a circular opening were used to standardize the dimensions of the denture base resin cylinders. Twenty specimens were produced for each denture base/acrylic tooth combination and were randomly divided into 2 groups (n=10). In control groups, the acrylic teeth surface did not receive any treatment. For experimental groups, the monomer liquid of corresponding acrylic resin MMA was applied on the acrylic teeth surface for 180 seconds. After, denture base resins were packed and polymerized according to manufacturer's instructions. The specimens were stored in distilled water (37^oC,50±2h) and shear strength tests (MPa) were performed at a crosshead speed of 1mm/min. Results:Data were statistically analyzed by 3-way ANOVA/Student's test (a=.05). Statistically significant interactions were found between surface treatment and denture base resins (p<.001) and between denture base resins and acrylic teeth (p=.005). Surface treatment with MMA resulted in an increase on the bond strength to L. However, the lowest shear bond strength was observed to Q and no difference was detected on the bond strength of A after treatment. Q exhibited significantly lowest bond strengths (p<.05) when associated with both acrylic teeth and the highest bond strength was observed with L/T. Conclusion:1)It was observed the influence of surface treatment with MMA on the bond strength of L and Q denture base resins. 2)The highest bond strength values were found with the combination L/T.