FRACTURE STRENGTH OF PALATAL DENTURE BASE CONSTRUCTED FROM DIFFERENT ACRYLIC DENTURE BASE MATERIALS

Abstract

Background: Acrylic resins constitute about 90% of polymeric materials used in prosthetic dentistry. However, they are not devoid of drawbacks. Their weakness includes poor resistance to fracture and abrasion, as well as changes in volume and shape during fabrication and use. Objectives: The aim of this study is to evaluate and compare the mechanical strength in fracture force test of maxillary palatal denture bases, fabricated from different acrylic resins. Materials and Methods: Twenty five maxillary edentulous stone casts were constructed from a standard silicon model of maxillary edentulous jaw. Five palatal denture bases were made from each of the following materials; conventional heat cure acrylic (Control Group), rapid cure acrylic, high impact acrylic and Biostar pure acrylic, according to the manufacturer’s instructions. The fracture force test was carried out on a universal testing machine (GUNT HAMBURG) at a crosshead speed of 10mm/min. The results were analyzed using ANOVA and t- test to determine the significant differences between tested groups at a significant level (P<0.05). Results: The high impact acrylic resin showed the highest fracture force value, while the Biostar pure acrylic resin showed the lowest value as compared with other tested materials. The results revealed highly significant differences between the high impact acrylic and conventional heat cure acrylic (P<0.001), and other tested denture base materials (P<0.05). Also, rapid heat cure acrylic resin showed significantly higher fracture force value than those obtained by both conventional heat cure acrylic resin and Biostar pure acrylic resin (P<0.05),(P<0.001) respectively. Finally, significantly lower fracture force value was obtained by the Biostar acrylic resin as compared to the conventional heat cure acrylic (P≤0.05) and other tested denture base materials (P<0.001). Conclusions: Under the limitation of this study for those patients who fracture their dentures on regular basis, it is possible to consider a high impact and rapid cure acrylic resins denture base, which shows a higher degree of resistance to fracture in comparison with conventional heat cure acrylic resin. However, this is unlike the Biostar pure acrylic resins that showed undesirable results as compared with conventional heat cure acrylic and other tested denture base materials.