Maciej Podgórski1, Eftalda Becka2, Mauro Claudino2, Alexander Flores2, Parag K Shah2, Jeffrey W Stansbury3, Christopher N Bowman4. 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, Denver, 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 assess the performance of thiol-ene dental composites based on selected ester-free thiol-ene formulations. Further, to point out the benefits/drawback of having a hydrolytically stable thiol-ene matrix within a glass filled composite. METHODS: Composite samples containing 50-65wt% of functionalized glass microparticles were prepared and photopolymerized in the presence of a suitable visible light photoinitiator. Shrinkage stress measurements were conducted as a function of the irradiation time. Degrees of conversion were measured by FT-IR analysis by comparing the double bond signals before and after photopolymerization. Mechanical tests were carried out on specimens after curing as well as after extended aging in water. Dynamic mechanical analysis was employed to track the changes in storage modulus near body temperature. The properties of the thiol-ene composites were compared with those of the BisGMA/TEGDMA control. RESULTS: Depending on the resin type, similar or higher conversions were achieved in thiol-ene composites when compared to the dimethacrylate controls. At comparable conversions, lower shrinkage stress values were achieved. Although exhibiting lower initial elastic moduli, the thiol-ene composites' flexural strengths were found to be comparable with the controls. Contrary to the control, the mechanical properties of the ester-free thiol-ene composites were shown to be unaffected by extensive aging in water and at least equaled that of the control after aging in water for just five weeks. SIGNIFICANCE: Employing non-degradable step-growth networks as organic matrices in dental composites will provide structurally uniform, tough materials with extended service time.
OBJECTIVES: To assess the performance of thiol-ene dental composites based on selected ester-free thiol-ene formulations. Further, to point out the benefits/drawback of having a hydrolytically stable thiol-ene matrix within a glass filled composite. METHODS: Composite samples containing 50-65wt% of functionalized glass microparticles were prepared and photopolymerized in the presence of a suitable visible light photoinitiator. Shrinkage stress measurements were conducted as a function of the irradiation time. Degrees of conversion were measured by FT-IR analysis by comparing the double bond signals before and after photopolymerization. Mechanical tests were carried out on specimens after curing as well as after extended aging in water. Dynamic mechanical analysis was employed to track the changes in storage modulus near body temperature. The properties of the thiol-ene composites were compared with those of the BisGMA/TEGDMA control. RESULTS: Depending on the resin type, similar or higher conversions were achieved in thiol-ene composites when compared to the dimethacrylate controls. At comparable conversions, lower shrinkage stress values were achieved. Although exhibiting lower initial elastic moduli, the thiol-ene composites' flexural strengths were found to be comparable with the controls. Contrary to the control, the mechanical properties of the ester-free thiol-ene composites were shown to be unaffected by extensive aging in water and at least equaled that of the control after aging in water for just five weeks. SIGNIFICANCE: Employing non-degradable step-growth networks as organic matrices in dental composites will provide structurally uniform, tough materials with extended service time.
Authors: Anuradha Prakki; Renato Cilli; Rafael Francisco Lia Mondelli; Sid Kalachandra; José Carlos Pereira Journal: J Dent Date: 2005-02 Impact factor: 4.379
Authors: Maciej Podgórski; Eftalda Becka; Mauro Claudino; Alexander Flores; Parag K Shah; Jeffrey W Stansbury; Christopher N Bowman Journal: Dent Mater Date: 2015-09-07 Impact factor: 5.304
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Authors: Han Byul Song; Xiance Wang; James R Patton; Jeffrey W Stansbury; Christopher N Bowman Journal: Dent Mater Date: 2017-03-28 Impact factor: 5.304
Authors: Maciej Podgórski; Eftalda Becka; Mauro Claudino; Alexander Flores; Parag K Shah; Jeffrey W Stansbury; Christopher N Bowman Journal: Dent Mater Date: 2015-09-07 Impact factor: 5.304