Effects of polyvinyl chloride film and oxygen-blocking gel on irradiance and depth of cure.

This study aimed to analyze the effects of polyvinyl chloride (PVC) film and oxygen-blocking gel (OBG) on the irradiance from an LED source and the depth of cure of a composite resin. Irradiance was measured with a curing radiometer, and curing depth was evaluated according to the methods described by the International Organization for Standardization (ISO 4049). Twelve experimental conditions were investigated in a 3 × 4 factorial design (n = 5 specimens per condition): no PVC film at the tip of the device, fitted PVC film, or misfit PVC film; and no OBG or a 1-, 2-, or 3-mm-thick layer of OBG. The data were analyzed using analysis of variance and Tukey tests (P < 0.05), and a linear regression test was performed between the variables (P < 0.05). The analyses showed that the variables under study influenced the irradiance (P < 0.05) but not the curing depth (P > 0.05). The 3 groups that did not have the PVC film and either did not have the OBG or had the OBG in a thickness of 1 or 2 mm were not significantly different from each other (P > 0.05) but presented the highest irradiance values among all the groups (P < 0.05). The use of the misfit PVC film with a 3-mm layer of OBG led to the lowest irradiance values (P < 0.05). The variables did not influence each other (P > 0.05). The results of this study indicated that the presence of PVC film, especially misfit film, reduced the irradiance. In addition, the greater the thickness of the OBG, the lower the irradiance. None of the PVC film barrier conditions or OBG thicknesses had an effect on the depth of cure.