Light initiation of dental resins: dynamics of the polymerization

Literature has shown that slowing down the curing rate of light-initiated resin composites by lowering the light intensity of the light source improved the integrity of the adhesive composite-cavity interface as a result of a more gradual contraction stress development. This study investigated how the curing rate could be controlled by varying the concentrations of the photoinitiator components in BisGMA-TEGDMA resin. Conversions and curing rates were evaluated by linear contraction experiments and Fourier transform infrared spectroscopy. Curing rates could be moderated significantly be reducing the concentrations of both photoinitiator and reducing agent without affecting the conversion, provided that the light exposure with a standard dental light curing unit lasts for 60 s.