Effect of unit and operatory lights on the consistency of light-activated composites

The extent to which the flow of composite resin is reduced when exposed to dental lights was studied. Samples were exposed to operating lights of various intensities for varying periods of time. After exposure each sample was placed under a fixed load and the resulting average diameter was calculated. Data from the testing of samples exposed to dental lights were analyzed by a two-way analysis of variance with subsequent Tukey multiple comparison test. Diameter comparisons were significant (p less than 0.05) between the controls and samples exposed to the 960 fc light at 6 minutes, the 1920 fc light at 4 minutes, the 2880 fc light at 2 minutes, and the 5120 and 7680 fc lights at 1 minute. The smaller diameters observed with respect to increased intensity and time of exposure show that either variable or the combination of both variables will alter the consistency of composite resin.