Visible light-cured composites and activating units. Council on Dental Materials, Instruments, and Equipment.

In summary, visible light-activated composites offer better regulation of working time. Their composition differs from chemically activated composites only in the initiators and activators. The physical and mechanical properties of adequately polymerized photoactivated composites are similar to chemically activated composites. Depth of cure evaluations of the photoactivated composites are dependent on many factors, both experimental and inherent. There is currently no consensus on depth of cure values and evaluation methods. It is suggested that, if necessary, visible light-activated composites should be placed and polymerized in about 2-mm increments. It is prudent to use a longer exposure time. Exposure of visible light composites to dental operatory lights or strong ambient lighting (or both) during restorative procedures should be minimized to avoid premature polymerization. There are differences in design, spectral distribution, and radiation intensity of photoactivating light units. No definitive information is currently available on the effectiveness and optimal conditions for use of different light/composite combinations. Little information is currently available on the bioeffect of visible light radiation on human optical systems and oral tissue. At the present time there are reports of afterimages but no long-lasting bioeffects. It is strongly recommended that precautions should be taken in the care, use, and operation of photoactivating light units. Protective filter glasses should be used.