The Physical Properties Of Auto-Polymerizing Hard Denture Relining Materials After Ultrasonical Cleaned With Ethanol Solutions

Abstract

Hard reline resin materials are commonly used to improve the fit of denture bases caused from resorption of the residual alveolar ridge. Major problem of resin is the presence of residual monomer after polymerization which had an adverse effect on the toxic and physical properties of the reline resin. Ethanol solutions in ultrasonic cleaner used been proven to reduce the residual monomer effectively in auto-polymerizing hard reline resins. The purpose of this study was to evaluate the flexural strength, flexural modulus, surface hardness, water sorption, and water solubility of four auto-polymerizing hard reline resins [Unifast Trad (UT), Kooliner (KL), Ufi Gel Hard (UG), and Tukuso Rebase II (TR)] after ultrasonic treatment with difference ethanol concentrations. For each material, ninety specimens were prepared and divided into 9 groups: negative control (NC): no treatment, positive controls: treated by immersion in water at 50°C for 1 hour (PC1), immersion in water at 55°C for 10 minutes (PC2) and the ultrasonic group, treated by immersion in 0%, 10%, 20%, 30%, 40% or 50% ethanol solution at 55°C for 5 minutes. The flexural strength and flexural modulus were determined using a three point transverse test. After that, one fragment of each specimen was analyzed using the Vickers microhardness test. The water sorption and solubility tests were performed per ISO No.20795-1. The data were analyzed by one-way ANOVA, Tukey's test, and Dunnett's test at a 95% confidence level. The results demonstrated significant differences in the level of flexural strength, flexural modulus, water sorption, and water solubility between the groups (p<0.05) within each specific auto-polymerizing hard reline resin, whereas there is no significant differences in the level of surface hardness between the groups of each specific material (p>0.05). Comparing in four types of auto-polymerizing hard reline resin after the same treatment method showed significant differences in level of flexural strength, flexural modulus, surface hardness, water sorption, and water solubility (p<0.05). UT demonstrated significantly higher flexural strength, flexural modulus, surface hardness, and water sorption than the other hard reline resins, whereas TR showed significantly higher water solubility than other materials. In conclusion, for KL, the 10% ethanol solution in ultrasonic cleaner should be the treatment of choice which effectively increases the physical properties. In UG and TR, the 10% ethanol solution in ultrasonic cleaner maintained the physical properties. In UT, the 30% ethanol solution in ultrasonic cleaner had appropriate physical properties.