A study of the diluent effect on the properties of urethane based dental composites
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Date
2003
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JOURNAL OF POLYMER MATERIALS
Abstract
Low molecular weight monomers such as triethylene glycol dimethacrylate (TEGDMA) and tetraethylene glycol diacrylate (TEGDA) have been conventionally used as diluents in combination with highly viscous dimethacrylate organic resins such as Bisphenol A - Glycidyl methacrylate (bis-GMA) in dental composite formulations to facilitate easier mixing and for providing improved properties. In this study a new low molecular weight dimethacrylate 1,3 bis (methactyloxy) 2-hydroxy propane [MHP] has been synthesized and used in dental composites. Glycidyl methacrylate was reacted with methacrylic acid in presence of a base catalyst, the product of which was subsequently used as a precursor for preparing two urethane tetramethacrylate resins by reacting with hexamethylene diisocyanate [HMDI] and toluene diisocyanate [TDI]. Dental composite pastes prepared using these two urethane resins had MHP or TEGDMA as diluents and dimethyl aminophenethyl alcohol [DMAPEA] or dimethyl p-toluidine [DMPT] as activators and their properties were compared. Comparisons were made in terms of compressive strength (CS), diametral tensile strength (DTS) and Vickers microhardness (MH). Composites containing HMDI showed improved mechanical properties compared to those prepared using TDI. Composites containing MHP showed comparable properties with those incorporated with TEGDMA. SEM studies showed evidence for uniform mixing of the filler in the urethane tetramethacrylate resin thinned with MHP.
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Polymer Science
Citation
20 ,1;59-66