The effects of halogen and light-emitting diode light curing on the depth of cure and surface microhardness of composite resins

Abstract

Aim:Light-emitting diode light curing units (LED LCUs) have become more popular than halogen LCUs in routine dental restorative treatment. The aim of the study was to compare the effects of two conventional halogen (Hilux Plus and VIP) and two LED (Elipar FreeLight 2 and Smart Lite) light curing units on the depth of cure and the microhardness of various esthetic restorative materials.Materials and Methods:The curing depth and microhardness of a compomer (Dyract Extra), a resin-modified glass ionomer (Vitremer), a packable composite (Sculpt It), an ormocer (Admira), a hybrid composite (Tetric Ceram), two microhybrid composites (Miris and Clearfil Photo Posterior) and, a nanofil composite (Filtek Supreme) were determined using a scraping method and a hardness tester. A total of 320 samples were prepared using the eight different materials (n = 10 samples for each subgroup). The scraping test was based on ISO 4049:2000. Vicker's microhardness testing was carried out using hardness tester (Zwick 3212). Data were analyzed using one-way analysis of variance (ANOVA), Bonferroni and the Kolmogorov–Smirnov tests.Results:Best microhardness results were obtained with the LED light curing units and Tetric EvoCeram and Filtek Supreme achieved the highest hardness values. The nanofil composite, Filtek Supreme, showed the best curing depth results in all the tested light curing systems.Conclusions:The LEDs were found to be more successful than the halogen units with respect to both curing depth and microhardness properties.

Effect of different light-curing techniques on hardness of a microhybrid dental composite resin

“…In general, when the thickness of dental structure was increased a decrease in the VHN mean values was observed [39,45,46]. Frequently, for the top surface, the VHN mean values were equivalent.…”

“…The purpose of micro indentation hardness testing is to obtain a numerical value that distinguishes between the relative ability of materials to resist controlled penetration by a specified type of indenter which is generally much harder than the material being tested [25,37]. In a way of determining degree of polymerization, several studies have compared hardness of dental composite resins [37,[39][40][41]. Now, clinicians face a dilemma when selecting a protocol for light-curing techniques of light-cured dental composite resins.…”

Influence of Curing Light Type and Staining Medium on the Discoloring Stability of Dental Restorative Composite

“…In terms of depth of cure, LED has been reported to cure similar or to increase depths through the resin composites (Apicella et al, 2002;Simeone et al, 2005;Ruchi et al, 2010). Considering the surface micro-hardness, several studies (Yaman et al, 2011) reported that LED-curing results is better micro-hardness than QTH. These results are suggesting that the type of curing light source may affect the level of polymerization and cross linking of the resin through the composite leading to higher surface hardness and glass transition temperatures.…”

Effects of Different Curing Unites on Bulk Fill Composites

“…The polymerization of light cured materials depends on their chemical composition, on the amount of filler particles, as well as on spectral output and irradiance of blue light emitted by light curing units (LCUs) [6][7][8]. Dentists may choose from different types of curing lights for the photo-polymerization of composites, such as conventional quartz tungsten-halogen (QTH/ HAL), light emitting diode (LED) curing units [9]. QTH/HAL is commonly preferred dental light curing unit [10].…”