Photoinduced polymerization of dental composite materials: Kinetics and optimization. pp.1077-1088
Authors: (Vitali T. Lipik, Vanda Yu. Voytekunas, Marc J. M. Abadie, University Montpelier 2, France, and others)
Abstract: Photopolymeric materials used in dentistry are complex composites which comprises of sometimes tens of components. The material should simultaneously carry out several functions and corresponds to requirements of thermostability, mechanical and chemical properties and to be nontoxic. Temperature of process, rate of polymerization and degree of polymerization has great value in the stomatologic practice . The properties are reached due to inclusion of certain combination of monomers, inorganic fillers, stabilizers, initiators of photopolymerization and other components in the material structure. In this work, the influence of combination of dental composites, lamps for photopolymerization and times of irradiation on the properties of final product was investigated. We studied the process of photopolymerization of five composite dental photopolymeric materials by using two lamps (Elipar FreeLight and Elipar FreeLight 2) and apparatus Du Pont 912 DS DSC with photocalorimeter Du Pont model 930 DPC. Highest polymerization enthalpy was achieved by Filtec Flow, while Filtec Suprem showed the lowest enthalpy among the 5 dental composites. The reaction rate coefficient, k, was established as well. At constant temperature, the highest k value was noted on Filtec Z250, while Tetric Ceram showed the lowest k value. The experiments for definition of temperature influence on polymerization process were conducted. Subsequently, the influence of temperature on polymerization process was studied. Polymerization of Filtec Z250 was found to be highly dependent on temperature whilst Filtec Flow and Restorativ Z100 were the least subjected to temperature effect. Our results also showed that Restorativ Z100 demands the least activation energy and Tetric Ceram requires the highest activation energy among all testing materials.