Influence of light-curing units on the polymerization of low-shrinkage composite resins

Abstract

This study examined the effect of various light-curing units (LCUs) on the polymerization of low-shrinkage composite resins. Two different types of low-shrinkage composite resins (silorane-based and methacrylate-based) were light cured using a quartz-tungstenhalogen (QTH) (HX) unit, a single-peak light-emitting diode (LED) (DM) unit, and a dual-peak LED (GL) unit, respectively. Among the tested LCUs, HX showed the lowest light attenuation within the specimens. Among the specimens, Aelite LS and Venus Diamond showed the highest and lowest light attenuation, respectively. Silorane-based Filtek LS showed the highest degree of conversion both on the top and bottom surfaces. On the bottom surface, Grandio and Aelite LS showed the lowest (4.5-7.1%) and highest (25.0-40.0%) decrease in the degree of conversion compared to their top surface. For different LCUs, within the same resin product, the microhardness was significantly different. The silorane-based composite resin showed significantly less polymerization shrinkage than the methacrylate-based nanofiller-containing composite resins.

Factors affecting marginal integrity of class II bulk-fill composite resin restorations

“…However, no differences were observed in gap formation with the use of composite resins polymerized in a similar manner with the use of different types of light-curing units, which coincides with the results of some previous studies. 42,43 Similarly, Lee et al 44 showed that the amount of polymerization shrinkage is a factor of the type and composition of composite resin, rather than the type of light-curing unit. …”

Influence of increment thickness on radiant energy and microhardness of bulk-fill resin composites

“…However, obtaining sufficient degree of conversion (DC) at all depths 8) may still be a challenge for these bulk fill resin composites. As mentioned above, the efficiency of the curing light decreases by absorption and scattering at increasing depth of resin composite materials 9) . Also, the type of the light curing unit used 10) , the translucency of the material 11) , the type and shade of the resin composite [12][13][14] , the distance of the light guide tip and the exposure time 15) are all factors that affect the overall light transmission through the resin composite.…”

Effects of Light Attenuation through Dental Tissues on Cure Depth of Composite Resins

“…In order to enhance clinical success of composite resin restorations, dental manufacturers have focused on the development of new light curing units, as well as the improvement of composite material composition. The introduction of nanotechnology enabled the development of composite resins with higher filler content, decreased filler size, as well as, enhanced composition in methacrylate-base organic matrix ( 4 , 5 ). Changing the monomer structure of composite resins also led low-shrinkage and tooth-colored silorane-based resins, composed of siloxane and oxirane molecules ( 5 - 9 ).…”