Evaluation of highly reactive mono-methacrylates as reactive diluents for BisGMA-based dental composites

Kilambi, Harini; Cramer, Neil B.; Schneidewind, Lauren H.; Shah, Parag; Stansbury, Jeffrey W.; Bowman, Christopher N.

doi:10.1016/j.dental.2008.05.003

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Volume 25, Issue 1 , Pages 33-38, January 2009

Evaluation of highly reactive mono-methacrylates as reactive diluents for BisGMA-based dental composites

Harini Kilambi
- Department of Chemical & Biological Engineering, University of Colorado, 1111 Engineering Drive, CB 424, Boulder, CO 80309, United States
Neil B. Cramer
- Department of Chemical & Biological Engineering, University of Colorado, 1111 Engineering Drive, CB 424, Boulder, CO 80309, United States
Lauren H. Schneidewind
- Department of Chemical & Biological Engineering, University of Colorado, 1111 Engineering Drive, CB 424, Boulder, CO 80309, United States
Parag Shah
- Department of Chemical & Biological Engineering, University of Colorado, 1111 Engineering Drive, CB 424, Boulder, CO 80309, United States
Jeffrey W. Stansbury
- Department of Chemical & Biological Engineering, University of Colorado, 1111 Engineering Drive, CB 424, Boulder, CO 80309, United States
- Biomaterials Research Center, School of Dentistry, University of Colorado Health Sciences Center, Aurora, CO 80045, United States
Christopher N. Bowman
- Department of Chemical & Biological Engineering, University of Colorado, 1111 Engineering Drive, CB 424, Boulder, CO 80309, United States
- Biomaterials Research Center, School of Dentistry, University of Colorado Health Sciences Center, Aurora, CO 80045, United States
- Corresponding author. Tel.: +1 303 492 3247; fax: +1 303 492 4341.

Received 12 February 2008; received in revised form 25 April 2008; accepted 10 May 2008.

Abstract

Objectives

This study evaluates the performance of highly reactive novel monomethacrylates characterized by various secondary moieties as reactive diluent alternatives to TEGDMA in BisGMA filled dental resins. We hypothesize that these monomers improve material properties and kinetics over TEGDMA because of their unique polymerization 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.

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 T_g values to the control, along with 27–37% reductions in the glass transition half widths indicating the formation of more homogeneous polymeric networks. The BisGMA/monomethacrylate formulations exhibited equivalent flexural modulus and flexural strength values relative to BisGMA/TEGDMA.

Significance

Formulations containing novel monovinyl methacrylates exhibit dramatically increased curing rates while also exhibiting superior or at least comparable composite polymer mechanical properties. Thus, these types of materials are attractive for use as reactive diluent alternatives to TEGDMA in dental formulations.

Keywords: Dental resins, Photopolymerization, Reactive diluent