Effect of ultrasonic treatment on the transverse strength of relined denture base with autopolymerizing acrylic hard reline material

Abstract

This study evaluated the effect of ultrasonic treatment and surface treatments on transverse strength of denture bases which relined with auto-polymerizing acrylic resin. The study groups, ninety heat-polymerized acrylic resins (64×10×2 mm) were divided by three surface treatments: no surface treatment (N), applied MMA for 180 seconds (MM), applied MF-MA for 15 seconds (MF). They were relined with auto-polymerized acrylic resin to create 64×10×3.3 mm specimens. Then, they were divided further by ultrasonic which were no ultrasonic (X), ultrasonic in water (W), ultrasonic in 30% ethanol (E). As a result, all test groups were classified as NX, NW, NE, MMX, MMW, MME, MFX, MFW, MFE (n=10). All samples were performed three-point bending test. Two-way ANOVA presented that there was an interaction between ultrasonic and surface treatments. Then One-way ANOVA was analyzed. Ultrasonic could increase transverse strength of all relined specimens (p<0.05). Ultrasonic in ethanol increased strength superior to water (p<0.05) and presented the highest mean strength. In the same ultrasonic treatment, MMA and MF-MA increased the transverse strength of relined denture bases compared with no applying groups (N) (p<0.05). There was no difference between all MM and MF groups (p>0.05).