Cure Depths of Resin Composite With Various LED Irradiance Exposures

Objectives: The purpose of this study was to determine the depth of cure (DOC) of two different types of resin-based composites (RBCs) using varying irradiance exposures with a corded LED curing unit.
Methods: DOC of two RBCs, Filtek Z250 (3M) and TPH Spectra (Dentsply Sirona) were determined using ISO Standard 4049. The RBCs were polymerized with a LED corded light [VALO (Ultradent)] using three different power settings and manufacturer’s recommended curing times (Standard, High and Xtra). Irradiance of the three different curing conditions was determined using a spectrometer sensor (checkMARC, BlueLight Analytics) and total energy density was calculated for each of the three power modes and concomitant polymerization time. DOC data were analyzed with a two-way analysis of variance and Tukey’s post hoc test.
Results: The DOCs using three polymerization conditions for TPH ranged from 2.69 (0.14) mm to 2.87 (0.12) mm and the DOCs for Z250 ranged from 3.04 (0.07) to 3.15 (0.26) mm. There was not a significant difference (p>0.05) in DOC for each RBC, but the Z250 DOCs were significantly greater (p<0.05) than TPH for two of the three polymerization conditions and near significance for the third.
Conclusions: The manufacturer’s recommended power mode and exposure time for each of the three polymerization conditions provided essentially the same DOC for each individual RBC material. However, there was a significant difference in DOC between the two RBCs evaluated in this laboratory study for two of the three light curing conditions with Z250 exhibiting greater DOCs than TPH.