Effectiveness of light emitting diode and halogen light curing units for curing microhybrid and nanocomposites

Abstract

Aim:To compare the polymerization efficacy of micro-hybrid and nanocomposites cured with Quartz-tungsten halogen (QTH) and light emitting diode (LED) light curing units (LCUs). The effectiveness of pulse cure mode in LED LCU was also investigated.Materials and Methods:Both micro-hybrid and nanocomposite specimens were cured using four different curing protocols giving a total of eight experimental groups. Ten cylindrical specimens were prepared for each group, and light cured for 40 s on the top surface, thus giving a total of eighty specimens. Vicker hardness measurements were carried out on the top and bottom surfaces after 24 h and hardness ratio was calculated.Results:For both micro-hybrid and nanocomposites, highest mean VHN was observed for the group cured with QTH LCU, and the lowest was observed for the group cured with second LED LCU in standard mode but the difference was significant only in case of nanocomposite.Conclusion:Curing nanocomposites with QTH LCU results in better micro hardness. Pulse cure mode does not effectively increase polymerization efficacy than the standard mode of curing.

Effect of temperature, curing time, and filler composition on surface microhardness of composite resins

“…The clinical performance of composite resins is directly related to the degree of monomer conversion after photopolymerization. [ 1 ] There are many parameters that influence degree of polymerization of composite resins such as their composition,[ 2 ] shade and translucency,[ 3 ] characteristics of the light-curing unit (LCU) used,[ 4 5 ] distance between light-curing tip and restoration surface,[ 6 ] duration of photopolymerization and composite temperature. [ 7 ]…”