Ester-free thiol-ene dental restoratives--Part A: Resin development

Maciej Podgórski; Eftalda Becka; Mauro Claudino; Alexander Flores; Parag K Shah; Jeffrey W Stansbury; Christopher N Bowman

doi:10.1016/j.dental.2015.08.148

Ester-free thiol-ene dental restoratives--Part A: Resin development

Dent Mater. 2015 Nov;31(11):1255-62. doi: 10.1016/j.dental.2015.08.148. Epub 2015 Sep 7.

Authors

Maciej Podgórski¹, Eftalda Becka², Mauro Claudino², Alexander Flores², Parag K Shah², Jeffrey W Stansbury³, Christopher N Bowman⁴

Affiliations

¹ Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, JSC Biotech Building, Boulder, CO 80309, USA; Department of Polymer Chemistry, Faculty of Chemistry, MCS University, Gliniana St. 33, 20-614 Lublin, Poland.
² Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, JSC Biotech Building, Boulder, CO 80309, USA.
³ Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, JSC Biotech Building, Boulder, CO 80309, USA; Department of Craniofacial Biology, School of Dental Medicine, University of Colorado, Anschutz Medical Campus, Mail Stop 8310, 12800E. 19th Avenue, Aurora, CO 80045, USA.
⁴ Department of Chemical and Biological Engineering, University of Colorado, 3415 Colorado Ave, JSC Biotech Building, Boulder, CO 80309, USA. Electronic address: christopher.bowman@colorado.edu.

Abstract

Objectives: To detail the development of ester-free thiol-ene dental resins with enhanced mechanical performance, limited potential for water uptake/leachables/degradation and low polymerization shrinkage stress.

Methods: Thiol-terminated oligomers were prepared via a thiol-Michael reaction and a bulky tetra-allyl monomer containing urethane linkages was synthesized. The experimental oligomers and/or monomers were photopolymerized using visible light activation. Several thiol-ene formulations were investigated and their performance ranked by comparisons of the thermo-mechanical properties, polymerization shrinkage stress, water sorption/solubility, and reactivity with respect to a control comprising a conventional BisGMA/TEGDMA dental resin.

Results: The ester-free thiol-ene formulations had significantly lower viscosities, water sorption and solubility than the BisGMA/TEGDMA control. Depending on the resin, the limiting functional conversions were equivalent to or greater than that of BisGMA/TEGDMA. At comparable conversions, lower shrinkage stress values were achieved by the thiol-ene systems. The polymerization shrinkage stress was dramatically reduced when the tetra-allyl monomer was used as the ene in ester-free thiol-ene mixtures. Although exhibiting lower Young's modulus, flexural strength, and glass transition temperatures, the toughness values associated with thiol-ene resins were greater than that of the BisGMA/TEGDMA control. In addition, the thiol-ene polymerization resulted in highly uniform polymer networks as indicated by the narrow tan delta peak widths.

Significance: Employing the developed thiol-ene resins in dental composites will reduce shrinkage stress and moisture absorption and form tougher materials. Furthermore, their low viscosities are expected to enable higher loadings of functionalized micro/nano-scale filler particles relevant for practical dental systems.

Keywords: Dental resin; Photopolymerization; Shrinkage stress; Thiol–ene.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Bisphenol A-Glycidyl Methacrylate
Composite Resins*
Materials Testing
Methacrylates
Pliability
Polyethylene Glycols
Polymethacrylic Acids
Stress, Mechanical
Sulfhydryl Compounds*

Substances

Composite Resins
Methacrylates
Polymethacrylic Acids
Sulfhydryl Compounds
Polyethylene Glycols
Bisphenol A-Glycidyl Methacrylate

Abstract

Publication types

MeSH terms

Substances

Grants and funding