The Influence of Different Light Curing Modes on the Depth of Cure of the Composite Resin

The aim of this study was to investigate the influence of different light curing modes on the depth of cure of the composite resin. The metal block with formed round holes served as a mold for the placement of the composite resin. The composite resin was cured with Penguin DB-685 lamp with four optional working modes: strong, low, gradually strong, and flashing. Unpolymerized part of the composite specimen was removed by scraping with a plastic spatula, and then each specimen was placed into the capsule with 1 ml of ethanol alcohol and mixed for 20 s in amalgamator. The length of the remaining composite specimen was measured with the digital caliper with a precision of 0.01 mm. The measured values were divided by 2 (according to ISO 4049 standard) and then statistically processed. Based on the measured lengths of the polymerized part of the composite specimens, the lowest average value of the depth of cure (2.75 +/- 0.08 mm) was determined after polymerization with the low mode and the highest value was obtained (2.98 +/- 0.08 mm) with strong polymerization mode. Statistically significant difference (p < 0.05) was determined between low polymerization mode and all other modes (strong, gradually strong and flashing mode). The observed statistically significant differences are not clinically important because all curing modes provided the necessary depth of cure, which is in accordance with the clinical recommendation of 2 mm thick composite layer.