Evaluation of Intensity of LED Curing Light on the Depth of Cure of Composite- An in Vitro Study

Aim: To evaluate the effect of intensity of curing light on depth of cure of resin based composite material and also to bring about the awareness to the dentists community regarding the maintenance of intensity of curing light unit.

Materials and Method: The resin based composite material of A2 shade was tightly packed into a plastic mould (fig1D) of diameter 6mm and depth 5mm. The sample size for each group was 10 in numbers, which was irradiated from the top, for each varying intensity, with light tip in nearest contact. An LED Light Curing unit was used throughout this study; the input voltage to the curing light was controlled by a regulated dc power supply. Four different settings of voltage 2.9V, 3.0V, 3.1V and 3.2V which yielded the light intensity as 200mW/cm², 250mW/cm², 300 mW/cm² and 375 mW/cm², the power supply to the curing light then was set to this voltage level i.e. 5V and the intensity was verified according to the ISO test method to determine the depth of cure of the resin-based composites.

Results: Statistical difference between the groups and among the groups were calculated using Students ‘t’ test. Results clearly shows a statistically significant difference in depth of cure with varying intensity of light used.

Conclusion: Depth of cure is comparatively low when intensity of curing light is low. These measurements provide valuable baseline information about the specific depth of cure for different intensities of curing light on resin-based composite materials used by dentists.