Effect of composite shade, increment thickness and curing light on temperature rise during photocuring

Abstract 

Objectives

To examine the effect of composite shade, increment thickness and curing light characteristics on the temperature rise associated with composite photocuring.

Methods

Four shades (C2, A4, B1 and B3), four sample thicknesses (2, 3, 4 and 5mm) of a hybrid resin composite and two curing units, one with two modes of curing, were investigated. The composite samples were packed in polytetrafluoroethylene (PTFE) moulds and cured for 40s. Samples cured with the ramp curing mode were irradiated for only 20s. Temperature rises on the undersurface of the curing resin composite were measured using an infrared scanning system.

Results

Shade C2 produced the highest maximum temperature of all shades (56.7°C). Thinner samples produced greater temperature rises (2mm induced 60.9°C, 5mm induced 45.7°C). Samples cured with Optilux 501 unit produced greater temperature rises (60.9°C) than those cured with Dentsply unit (56.2°C).

Conclusions

There was a quantifiable amount of heat generated during visible light curing of resin composite. The amount of heat generated was influenced by shade selected, thickness of material and characteristics of the light curing unit.

Keywords: Thermography, Temperature rise, Curing units, Shade, Resin composite, Composite increment thickness