Improved polymerization efficiency of methacrylate-based cements containing an iodonium salt

Author(s)

Goncalves, Luciano S. ^{[1, 2]} ; Moraes, Rafael R. ^[3] ; Ogliari, Fabricio A. ^[4] ; Boaro, Leticia ^[5] ; Braga, Roberto R. ^[6] ; Consani, Simonides ^[1]

Affiliation

^[1] Univ Estadual Campinas, Piracicaba Dent Sch, Campinas, SP - Brazil

^[2] Univ Uberaba, Sch Dent, Uberaba, MG - Brazil

^[3] Univ Fed Pelotas, Sch Dent, Pelotas - Brazil

^[4] Univ Fed Pelotas, Mat Engn Sch, Pelotas - Brazil

^[5] Univ Santo Amaro, Sch Dent, Sao Paulo - Brazil

^[6] Univ Sao Paulo, Sch Dent, BR-05508 Sao Paulo - Brazil

• Document type: Journal article
• Source: Dental Materials; v. 29, n. 12, p. 1251-1255, DEC 2013.
• Web of Science Citations: 19

Abstract

Objective. This study evaluated the effect of adding diphenyliodonium hexafluorphosphate (DPI) as a third component of the free-radical photoinitiator system of model resin cements on their photopolymerization kinetics/stress and fundamental properties. Methods. A model resin cement containing a 1:1 mass ratio of 2,2-bis{[}4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane and triethyleneglycol dimethacrylate was obtained. Camphorquinone (1 mol%) and 2-(dimethylamino)ethyl methacrylate (2 mol%) were added to monomer blend. Six mixtures were obtained by incorporation of 0 (control), 0.25, 0.5, 1, 2, or 4 mol% of DPI. The cements were loaded with a 60% mass fraction of silanated glass fillers. Polymerization kinetics (using Fourier-transform near-infrared spectroscopy), flexural strength and modulus, water uptake/solubility, and polymerization stress were assessed. Data were statistically analyzed using one-way ANOVA and Student-Newman-Keuls' test (P <= 0.05). Results. In the DPI-modified materials, the onset of autodeceleration occurred earlier and at higher conversion compared with the control cement. The addition of DPI also led to a more active early-stage polymerization. The flexural modulus was generally higher for DPI-containing materials. Water uptake and solubility were generally lower for materials with DPI fractions >= 0.5%. Significant increase of polymerization stress was observed only in the group with 1 mol% of DPI compared with the control cement. Significance. The effect of DPI on the photopolymerization reactivity of the cement is concentration-dependent; the use of DPI could result in better polymerization efficiency of resin-based cements. (C) 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved. (AU)