Evaluation of hardness and degree of conversion of different bulk-fill materials cured with Quartz Tungsten Halogen and light emitting diode devices

Abstract

Aims: The aim of this study is to evaluate the hardness and degree of conversion (DC) of different bulk-fill materials when cured with the Quartz Tungsten Halogen (QTH) and Light emitting diode (LED) devices using same energy density. Settings and Design: This was in vitro study. Materials and Methods: Three different bulk-fill materials, i.e., Filtek™ [3M ESPE], Tetric® N-Ceram [Ivoclar Vivadent], and SDR (Smart Dentin Replacement) by Dentsply Caulk, were used for making 180 samples (60 samples each) in Teflon mold. Out of these 60 samples, samples of three heights were prepared, i.e., 2 mm, 4 mm, and 6 mm (20 each). All the sample molds were filled in single increment and were exposed to the QTH and LED using the same energy density. Then, these samples were tested for microhardness using the Vickers hardness (VH) testing machine (Mitutoyo, Japan) and DC using Fourier Transform Infrared Spectroscope (Cary 630 FTIR Agilent Technologies, Germany). Statistical Analysis Used: The statistical analysis was performed on the collected data. The Kolmogorov–Smirnov and Shapiro–Wilk tests showed that the data are normally distributed. Since all the variables were continuous and statistically independent, independent t-test was applied to compare mean values of VH and DC of inter groups. Results: The statistical analysis of readings revealed that there was no significant difference in the mean values of microhardness and % DC for both groups cured by QTH and LED. Conclusions: It can be concluded that irrespective of the type of the light cure unit if the energy density applied is same then almost similar performance can be expected from the devices.

Keywords

• bulk-fill composites
• curing lights
• degree of conversion
• microhardness
• same energy density