Factors affecting the energy delivered to simulated class I and class v preparations

To determine the effect of operator, curing light and preparation location, as well as any correlations among these variables, on the amount of light energy delivered to simulated cavity preparations.

Each of 10 dentists and 10 fourth-year dental students light-cured a Class I preparation in tooth 26 and a Class V preparation in tooth 37 in a dental mannequin head. The operators exposed each preparation for 10 seconds with each of 3 LED-based curing lights (Bluephase G2 on high power, Demi and VALO on standard power). Each operator also used the VALO unit in the plasma mode for 2 sequential 3-second curing cycles. For each combination of operator, curing light and preparation, the irradiance (mW/cm(2)) received at the base of the preparation was measured with a laboratory-grade spectroradiometer, and software was used to calculate the energy density delivered in real time. The statistical analysis included 3-way analysis of variance (ANOVA) and the Fisher protected least significant difference (PLSD) test for post hoc pairwise comparisons.

There was a large qualitative and quantitative variation in the irradiance delivered to the preparations by each operator. Three-way ANOVA showed no statistically significant differences between dentists and dental students in terms of the amount of energy delivered (p = 0.90). However, there were statistically significant differences in energy delivered by the various curing lights (p < 0.001) and between the 2 preparation locations (p < 0.001). According to the Fisher PLSD test for post hoc pairwise comparison of means, the VALO unit used in the plasma mode for two 3-second curing cycles delivered the most energy (16.4 +/- 3.1 J/cm(2)) to the Class I preparation, and the same light used for 10 seconds in the standard mode delivered the least amount of energy (9.9 +/- 2.4 J/cm(2)) (p < 0.001). For the Class V preparation, the VALO unit used in the plasma mode for two 3-second curing cycles delivered the most energy (12.5 +/- 4.0 J/cm(2)), and the Demi unit, used for 10 seconds, delivered the least energy (7.4 +/- 2.5 J/cm(2)).

The energy delivered by a curing light to a preparation in a simulated clinical environment was affected by the operator's light-delivery technique, the choice of curing light and the location of the preparation.