Factors Affecting the Energy Delivered to Simulated Class I and Class V Preparations(9)

tor at the Class I location. Conversely, Fig. 5 shows that the Class V preparation in tooth 37 was difficult to access for lights with a light guide, such as the Demi and Bluephase G2 curing lights. It was difficult for the operators to position these units directly over the Class V preparation because of limited space between the rubber cheeks of the mannequin and the tooth, and the energy density delivered was reduced accordingly (Table 4). A similar result would be expected in the clinical setting, with the patient's cheek interfering with positioning of the tip of the light guide directly over a Class V preparation. Although it was easier to reach the Class V preparation with the VALO unit, this light, when operated in the plasma mode, had a higher coefficient of variation (0.32) at the Class V location than the Class I location, possibly because the light had to be turned on twice to perform the two 3-second curing cycles. This manoeuvre required some repositioning of the light by the operators.

On the basis of a previous study,¹ the target for energy delivery was set at 10 J/cm², with the knowledge that more or less energy might be required to adequately polymerize some resins.^1-7 The fact that many operators could not deliver the clinically relevant energy density of 10 J/cm² suggests that some resin restorations placed in