Contemporary issues in photocuring.

Currently, there is much confusion regarding differences among the variety of light-curing units on the market. Units range from conventional, fixed, continuous output quartz-tungsten-halogen (QTH) models, to very high-intensity systems such as the plasma-arc (PAC) units and the argon-ion lasers. Also, a trend has been established for purposefully providing low light intensity output during initial phases of the curing exposure: the so-called "soft-start" method. Proponents of this method state that by decreasing the rate at which a photoactivated resin cures, stress buildup at the tooth/restoration interface can be minimized, resulting in enhanced marginal integrity.