Influence of UEDMA, BisGMA and TEGDMA on selected mechanical properties of experimental resin composites

Objectives. This study was conducted to determine the effect of UEDMA, BisGMA and TEGDMA on selected mechanical properties of experimental resin composites. Methods. Thirty monomer mixtures of TEGDMA and BisGMA and/or UEDMA were produced. Five base monomer mixtures had the following molar relationships between TEGDMA and BisGMA: 30:70, 40:60, 50:50, 60:40 and 70:30. Monomer mixtures were then produced in which BisGMA was successively substituted by UEDMA, 10 mol% at a time. The resins were made light-curing and loaded with filler. Diametral tensile strength, flexural strength and modulus of elasticity were determined on 1 week old specimens. The results were analyzed by ANOVA and by response surface methodology. Results. The diametral tensile strength of the resin composites varied between 52 and 59 MPa, the flexural strength between 137 and 167 MPa, and the modulus of elasticity between 8.0 and 11.1 GPa. The statistical analyses showed that substitution of BisGMA or TEGDMA by UEDMA resulted in an increase in tensile and flexural strength, and that substitution of BisGMA by TEGDMA increased tensile, but reduced flexural strength. Further, it was found that, for a given content of UEDMA, variations in the ratio BisGMA/TEGDMA gave rise to a maximum in modulus of elasticity. The size of this maximum in modulus decreased with increasing content of UEDMA. Significance. Varying the relative amounts of UEDMA, BisGMA and TEGDMA has a significant effect on the mechanical properties of the resin composition. Thus, by selecting specific combinations of these components, it may be possible to design composites with properties that are tailor made to specific applications. (C) 1998 Academy of Dental Materials. Published by Elsevier Science Ltd.