Depth of cure and microleakage with high-intensity and ramped resin-based composite curing lights.

Background: The authors conducted a study to determine whether high-intensity curing lights in high and ramped intensity modes affect microleakage of resin-based composite restorations and whether different types of resin-based composites meet American National Standards Institute/American Dental Association Specification no. 27 (1993): 7.7 for depth of cure when polymerized using these lights.

Methods: The authors compared five high-intensity lights, three plasma arc lights and two quartz-tungsten-halogen lights in their regular and ramped intensity modes with a quartz-tungsten-halogen 40-second light. The parameters tested were microleakage one month after bonding and curing depth for different resin-based composite types. The authors measured curing depth using a scratch test.

Results: Light curing with Optilux 501 (Kerr/Demetron, Orange, Calif.) for 10 seconds and ADT Power PAC (American Dental Technologies, Corpus Christi, Texas) for 10 seconds resulted in higher microleakage values than light curing with other lights (P < .05). The microhybrid resin-based composite was the only material that met the specification when light cured with all of the lights tested. The flowable resin-based composite did not meet the specification when light cured with all lights tested. Microhybrid resin-based composite had the greatest depth of cure, and flowable resin-based composite had the least depth of cure.

Conclusions: Microhybrid resin-based composite microleakage is affected by some light-curing modes. Different categories of resin-based composites are cured to different depths using high-intensity lights.

Clinical Implications: Light curing with some high-intensity lights compared with halogen lights may result in higher microleakage values. Use caution when light curing flowable resin-based composite with the high-intensity lights. Place increments less than 2 millimeters in depth when using this material.