Factors Affecting the Energy Delivered to Simulated Class I and Class V Preparations(7)

The energy delivered by the operators to the Class I preparation site (Table 2) and the Class V preparation site (Table 3) varied by individual operator and with curing light. To determine the practical implications of this variation, it is useful to compare the energy density delivered with the minimum energy density required to ensure that the bottom 2 mm of Filtek Supreme composite, shade A2B (3M ESPE, St. Paul, MN), reaches the clinically acceptable level of 80% of surface hardness (10 J/cm²).¹ For the Class I preparation, the percentage of operators who delivered the minimum energy density of 10 J/cm² was 95% with the VALO unit in plasma mode and 90% with the Bluephase G2 unit (Table 2). However, using the Demi unit and the VALO unit in standard mode, only 70% and 65% of the operators, respectively, delivered 10 J/cm². For the Class V preparation, the percentage of operators who delivered the minimum of 10 J/cm² was lower for each curing light: 70% for the VALO unit in plasma mode, 50% for the VALO unit in standard mode, 20% for the Bluephase G2 unit and 15% for the Demi unit (Table 3).

Summary statistics for the total light energy delivered by all operators (n = 20) are reported in Table 4. In general, the coefficient of variation for a given curing light was greater for the Class V preparation, except for the VALO unit operated in standard mode for 10 seconds. (Table 4). The correlations determined by 3-way ANOVA (Table 5) indicated no significant difference between dentist and student operators (p = 0.90). However, as a group, the 20 operators delivered significantly less energy to the Class V preparation than to the Class I preparation (p < 0.001). There was also a significant difference in the amount of energy delivered by each curing light (p < 0.001). At the Class I location, the VALO unit operated in plasma mode for two 3-second cycles delivered the most energy (16.4 ± 3.1 J/cm²) and the same unit operated in standard mode for 10 seconds de