Polymerization of dental composite resins using plasma light

Chemical and morphological features of dental composite resin: Influence of light curing units and immersion media

“…Polymerization reaction occurs when there is light incidence with a wavelength within absorption spectrum of the photoinitiator and with enough intensity to keep it at the excitation state, thus enabling it to react with the reduction agent (Amina-N) and form free radicals for a cascade reaction to begin (Blankenau et al, 1983;Fano et al, 2002;Nomoto, 1997).…”

Influence of heat from light curing units and dental composite polymerization on cells in vitro

“…19,20 The temperature increase within the pulp chamber during the light polymerization process was extensively discussed recently in cause of the introduction of plasma light curing units using a high light power. [21][22][23] It was concluded that high power LCUs may represent a potential hazard for the tooth depending on the light power and application time of the LCU. Since 1965, the controversially discussed threshold for a hazardous temperature increase within the pulp chamber is 5.5 and 11.1 8C which caused irreversible pulpitis in 15 and 60% of Macaca Rhesus monkey teeth.…”

Comparison between a silorane-based composite and methacrylate-based composites: Shrinkage characteristics, thermal properties, gel point and vitrification point

“…Visvanathan et al 6) proposed polymerization shrinkage force as an indirect measure of gel point, and that gel point was arbitrarily defined as the time needed to exceed a force threshold of 0.5 N. In the same vein, Fano et al 7) proposed that the maximum shrinkage strain rate of resin composites occurred at gel point, citing the reason that auto-acceleration of polymerization rate was due to "gel effect" 8) . At gel point, shrinkage strain rate was at its highest because polymerization shrinkage was hindered by a build-up of three-dimensional networks of polymer chains, resulting in a dramatic physical change as well as dramatically improved mechanical and physical changes 7) . No generally accepted criteria and measurement protocols have been defined for monitoring and identifying vitrification points 9) .…”