Effect of Ethylmethacrylate and Isobutylmethacrylate on surface hardness and surface roughness of heat-cure ocular acrylic resins


Background Acrylic resin is a commonly utilized material in clinical practice, including: maxillofacial prosthesis Interim prostheses, repair dentures, reline, orthodontic equipment, and record bases are only a few examples of possible applications. However, these materials have some drawbacks, for example low mechanical properties. To improve the performance of the acrylic resins, various materials have been incorporated. Purpose: The purpose of this research was to assess the effect of adding different concentrations of copolymers of Ethyl methacrylate (EA) and Isobutyl methacrylate (IBMA) monomers on some of the mechanical properties of acrylic resin such as surface hardness and surface roughness.Approach: 100 samples were made of acrylic resin and divided into three groups (a control group and two experimental groups) and 20 samples for the control group and these samples were divided into ten samples for each group based on the tests performed. 40 samples per experimental group (IBMA, EMA) divided into two groups according to the added concentration (1% and 2%). Then, according to the tests performed, each group was divided into two groups with ten samples for each group. Acrylic samples were fabricated with dimensions of 65 mm x 10 mm x 2.5 lengths, width and thickness respectively according to (ADA specification, No.12, 1999). Each specimen was subjected to the surface hardness test and surface roughness test. All data were analyzed using SPSS version 20, One –way ANOVA, LSD and Post Hoc -Tukey test were utilized for detecting the significant differences and multiple comparisons.Results: The control group had the greatest mean value of hardness compared with the experimental group while the EMA 1% group showed the lowest mean value of roughness test compared with the control and other experimental groups.Conclusion: The incorporation of experimental groups (IBMA, EMA) in different concentrations by weight in MMA and PMMA had a decrease slightly of surface hardness of acrylic resins, and the incorporation of EMA 1% by weight in MMA and PMMA had improved surface roughness. In added EMA2%, IBMA 2% enhanced slightly the surface roughness of acrylic resins