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The aim of the present work is the study of some physicochemical properties of two current commer- cial dental self-curing two component composites, i.e., of Concise TM (3M TM , Dental Products, St. Paul, USA), and Alfacomp (VOCO GmbH, Germany). Based on their filler type Concise is characterized as ''conventional'' or ''macro- filled'' composite and Alfacomp as ''hybrid.'' The resin matrix of Concise is a copolymer of 2-bis(4-2-hydroxy-3- (methacryloxy)-propyl)phenyl propane (Bis-GMA)/triethy- leneglycol dimethacrylate, while that of Alfacomp a homo- polymer of Bis-GMA. The composites were prepared in accordance with the manufacturers' instructions by mixing equal amounts of the two components at room tempera- ture. The degree of conversion of double bonds of resin matrix during curing was determined in thin film of com- posites using FTIR transmission spectroscopy. The degree of conversion of Concise and Aflacomp was found to be correspondingly (73.63 6 4.33)% and (47.75 6 1.80)% after a day-polymerization. Sorption, solubility, and volumetric change were determined after storage of composites in water or ethanol/water solution 75 vol % at 37 � C (a good food/oral simulating fluid) for 30 days. These properties for both composites were higher in ethanol/water solution than in water. Also these properties for Concise were lower than those for Alfacomp in both liquids. Thermal stability of composites was studied by thermogravimetric analysis which performed in air atmosphere from 50 to 800 � C. This analysis of composites showed the degrada- tion of their resin matrix in three steps. The organic resin content of Concise was found to be 18.0% w/w and that of Alfacomp 20.1% w/w. Concise showed generally better properties than Alfacomp. This behavior must due to the dif- ferences in the chemical structure of the organic resin matrix and the type of inorganic filler. V C 2012 Wiley Periodicals, Inc. J Appl Polym Sci 126: 367-374, 2012 |
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