Effect of Diluent Monomer on the Physical Properties of Bis-GMA-based Composites

Abstract

The nature of the bis-GMA diluent present in composite formulations greatly affects such properties of the cured resin as setting time, strength, water sorption, and coefficient of thermal expansion. J Dent Res 60(6):983-989, June 1981 Introduction.Composite resins comprise the majority of anterior dental restorations. These materials have many desirable properties; however, their overall performance (in particular, their finishing, wear resistance, adaptation to cavity walls, color and storage stability, adhesion to tooth surface, and biocompatibility) indicates a need for improvement.Most commercial materials use bis-GMA as the major monomeric ingredient. This substance has a molasses-like viscosity. To obtain pastes or liquids that can be mixed readily in the dental operatory, monomeric diluents are incorporated into the composite formulations. The role of the composition of the organic (polymerizable) phase in determining the wall-to-wall polymerization contraction of composite restorative resins has been demonstrated by Asmussen.1 Thus, the diluent monomer employed may influence the physical properties, as well as the marginal adaptation of bis-GMA-based composites. Different diluent monomers vary in chain length, viscosity, surface tension, storage stability, and solubility compatibility with bis-GMA. These properties affect the mixing characteristics and the polymerization of the material. Cured resins with different molecular weight, crosswhich must be minimized for a restoration possessing optimal marginal adaptation.The objective of this study was to determine the effect of the diluent monomer on the physical properties of both the monomer solution and the cured resin in the bis-GMA-based powder-liquid system. In subsequent work we will determine the influence of diluent on the marginal adaptation of dental composite restorations. Thus, the results of this study will allow the selection of composites with desirable characteristics for the subsequent measurements of marginal leakage.Materials and methods.* Preparation of liquid. -Liquids were prepared containing 0.2% bis-GMA and 0.23% butylated hydroxytoluene (BHT) as inhibitor.N,N-dimethyl-p-toluidine (DMPT) and various diluents of two main types were used: 1) RO(CH2)nOR where R = methacryl (H2C = 9-) and n = CH3 2, 4, 6, 10 (hydrocarbon diol series) and 2) RO(CH2CH20)nR, where n = 2, 3,^4 (glycol ether series). These and other miscellaneous diluents used in this study are given in Table 1. All diluents were used as received. To better compare the effect of the diluent component of the liquid on physical properties of the cured composites, various diluent concentrations were incorporated into the formulations.

Effect of Curing Mode on Microtensile Bond Strength to Dentin of Two Dual-cured Adhesive Systems in Combination with Resin Luting Cements for Indirect Restorations

“…Composed of a high concentration of hydrophobic monomers, such as Bis-GMA (Table 1), Pre-Bond adhesive resin may create a hybrid layer with a high concentration of hydrophobic monomers and, consequently, lower hydrophilicity, [14][15][16] thus improving its mechanical properties. [17][18] Moreover, dual-curing mechanisms within the hybrid layer may have contributed to the higher µTBS when Pre-Bond resin infiltrated the primed dentin surface. Considering that All Bond 2 Primer A contains a tertiary amine as a component for the self-curing reaction, 12 and Pre-Bond resin has benzoyl peroxide, it is possible that free-radicals within the hybrid layer might have been created not only from light activation, but also from the self-curing redox reaction.…”

Development of dental resin luting agents based on Bis-EMA4: bond strength evaluation

“…Due to its high viscosity, the Bis-GMA is usually diluted with triethylene glycol dimethacrylate (TEGDMA) [2]. However, TEGDMA has been linked to increased water sorption and polymerization shrinkage [2][3][4]. In order to overcome the drawbacks of the dilution process using TEGDMA, ethoxylated bisphenol A glycol dimethacrylate (Bis-EMA) has been investigated as an alternative monomer [5][6].…”

Effects of filler composition on flexibility of microfilled resin composite

“…10 It also has been reported that mechanical properties of crosslinked polymer prepared with polyfunctional monomers were influenced by the properties of reactive groups, including chain length and rigidity. [11][12][13][14][15][16][17] The results indicated that cross-linked polymers, having a short and rigid chain between double bonds, exhibited lower impact strength.…”