Ester-free thiol–ene dental restoratives—Part B: Composite development. Issue 11 (November 2015)

• Record Type: Journal Article
• Authors: Podgórski, Maciej; Becka, Eftalda; Claudino, Mauro; Flores, Alexander; Shah, Parag K.; Stansbury, Jeffrey W.; Bowman, Christopher N.
• Is Part Of: Dental materials. Volume 31:Issue 11(2015)
• Page Start: 1263
• Page End: 1270
• Publication Date: 2015-11
• Subjects: Dentistry -- Periodicals; Dental materials -- Periodicals; 617.695
• DOI: 10.1016/j.dental.2015.08.147
• Languages: English
• ISSNs: 0109-5641

Abstract

<abstract abstract-type="author" id="abs0005"> <title id="sect0005">Abstract</title> <sec> <title id="sect0010">Objectives</title> <p id="spar0005">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.</p> </sec> <sec> <title id="sect0015">Methods</title> <p id="spar0010">Composite samples containing 50–65 wt% 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.</p> </sec> <sec> <title id="sect0020">Results</title> <p id="spar0015">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.</p> </sec> <sec> <title id="sect0025">Significance</title> <p id="spar0020">Employing non-degradable step-growth networks as organic matrices in dental composites will provide structurally uniform, tough materials with extended service time.</p> </sec> </abstract>