Novel Urethane-Dimethacrylate Monomers and Compositions for Use as Matrices in Dental Restorative Materials.

Izabela M Barszczewska-Rybarek,Marta W Chrószcz,Grzegorz Chladek

doi:10.3390/ijms21072644

Izabela M Barszczewska-Rybarek, Marta W Chrószcz + Show 1 more

Open Access

https://doi.org/10.3390/ijms21072644

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Abstract

In this study, novel urethane-dimethacrylate monomers were synthesized from 1,3-bis(1-isocyanato-1-methylethyl)benzene (MEBDI) and oligoethylene glycols monomethacrylates, containing one to three oxyethylene groups. They can potentially be utilized as matrices in dental restorative materials. The obtained monomers were used to prepare four new formulations. Two of them were solely composed of the MEBDI-based monomers. In a second pair, a monomer based on triethylene glycol monomethacrylate, used in 20 wt.%, was replaced with triethylene glycol dimethacrylate (TEGDMA), a reactive diluent typically used in dental materials. For comparison purposes, two formulations, using typical dental dimethacrylates (bisphenol A glycerolate dimethacrylate (Bis-GMA), urethane-dimethacrylate (UDMA) and TEGDMA) were prepared. The monomers and mixtures were tested for the viscosity and density. The homopolymers and copolymers, obtained via photopolymerization, were tested for the degree of conversion, polymerization shrinkage, water sorption and solubility, hardness, flexural strength and modulus. The newly developed formulations achieved promising physico-chemical and mechanical characteristics so as to be suitable for applications as dental composite matrices. A combination of the MEBDI-based urethane-dimethacrylates with TEGDMA resulted in copolymers with a high degree of conversion, low polymerization shrinkage, low water sorption and water solubility, and good mechanical properties. These parameters showed an improvement in relation to currently used dental formulations.

Highlights

The world population growth, population ageing, high expectations of reconstruction quality and aesthetics, as well as increasing dental health awareness result in a continuous increase in the demand for composite dental restorative materials [1,2]
This work aimed at the development of new bisphenol A (BPA)-free resin formulations, based on new urethane-dimethacrylates, that could offer similar or better physico-mechanical properties than those which are based on bisphenol A glycerolate dimethacrylate (Bis-GMA), urethane-dimethacrylate monomer (UDMA) and triethylene glycol dimethacrylate (TEGDMA)
The analysis of the results showed that the MEBDI-based copolymers constituted wholly of urethane-dimethacrylates had a greater hardness when compared to those containing TEGDMA

Summary

Introduction

The world population growth, population ageing, high expectations of reconstruction quality and aesthetics, as well as increasing dental health awareness result in a continuous increase in the demand for composite dental restorative materials [1,2]. The main advantages of Bis-GMA include the relatively low polymerization shrinkage, suitable mechanical properties and excellent adhesion to enamel The disadvantages of this compound include an extremely high viscosity and low degree of conversion (DC) [6,7,8], which impose the need for mixing the Bis-GMA with other, less viscous monomers, such as reactive diluents. TEGDMA is responsible for a decrease in the mechanical strength [12], along with an increase in polymerization shrinkage [4] and water sorption [13,14] These limitations led to the development of other dimethacrylate resins, such as Bis-EMA. This has a significantly lower viscosity and water sorption than Bis-GMA, polymerizes to a higher DC, and has a higher mechanical strength [11]. It is more elastic than Bis-GMA [11] and has a worse adhesion to the enamel [4]

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