Highly Reactive Monomethacrylates as Reactive Diluents for Dimethacrylate-Based Dental Composites

Objectives: The objective of this work was to investigate the use of highly reactive monovinyl methacrylates as reactive diluents for dimethacrylate-based dental composites. We hypothesize that these monomers improve material properties and kinetics over TEGDMA because of their unique behavior. Methods: The cure rates and final double bond conversion of the resins were measured using real-time FTIR spectroscopy. The glass transition temperature and storage modulus of the formed polymers were measured using dynamic mechanical analysis. Flexural modulus and flexural strength values were obtained using a three-point bending flexural test carried out with a MTSŪ 858 Mini Bionix system. Results: Polymerization kinetics and polymer mechanical properties were evaluated for the novel resin composites. It was observed that upon the use of novel monomethacrylates as reactive diluents, polymerization kinetics increased by up to 3-fold accompanied by increases in the extent of cure from 5% to 13% as compared to the BisGMA/TEGDMA control. Polymer composites formed from resins of BisGMA/novel monomethacrylates exhibited comparable Tg values to the control, along with 27-37% reductions in the glass transition half widths indicating the formation of a more homogeneous material. The BisGMA/monomethacrylate formulations exhibited equivalent flexural modulus and flexural strength values relative to BisGMA/TEGDMA.

Conclusions: Formulations containing highly reactive monovinyl methacrylates exhibit dramatically increased curing efficiency and cure rates while also exhibiting superior or comparable composite polymer mechanical properties. Thus, these types of materials are attractive for use as reactive diluent alternatives to TEGDMA in dental formulations. Supported by NIH DE grant #10959 and NIDCR F32 DE15906.