Factors Affecting the Energy Delivered to Simulated Class I and Class V Preparations(8)

livered the least (9.9 ± 2.4 J/cm²) (p < 0.05; Fisher PLSD test for post hoc pairwise comparisons). At the Class V location, the VALO unit operated in plasma mode for two 3-second cycles delivered the most energy (12.5 ± 4.0 J/cm²), and the Demi unit, operated for 10 seconds, delivered the least energy (7.4 ± 2.5 J/cm²) (p < 0.05; Fisher PLSD test for post hoc pairwise comparisons).

 

 

Discussion

As shown in Tables 4 and 5, the light energy delivered to the Class I (Table 2) and Class V (Table 3) preparations varied significantly among the 20 operators (the range was from 2.6 J/cm² to 20.4 J/cm²). Furthermore, the energy density delivered to the Class V preparation in the buccal region of tooth 37 was markedly less than that delivered to the occlusal Class I preparation in tooth 26 for 3 of the 4 experimental conditions (VALO unit used for two 3-second cycles in plasma mode, Bluephase G2 unit used for 10 seconds in high power mode and Demi unit used for 10 seconds). This difference indicates that accessibility to a restoration site has a significant effect on the clinician's ability to deliver adequate energy from the curing light to the restoration. Figs. 2 and 3 provide qualitative examples of the ability of the MARC system to track the irradiance delivered over time by each clinician. Using the same curing lights, one operator (Figs. 2a and 3a) delivered much higher and more consistent irradiance and energy than another operator (Figs. 2b and 3b) for the same types of restorative scenarios. This difference in performance illustrates the critical role of operator technique in delivering adequate energy density to a restoration. The VALO unit, used in the plasma mode for two 3-second cycles, had a low coefficient of variation (0.19) in the amount of energy delivered at the Class I location. Fig. 4 illustrates how the curved lens at the end of this curing light rested between the cusp tips, which would help the operator to stabilize the light over the detec