Several studies have measured the curing depth or degree of conversion, combined with other properties such as hardness or flexural strength or residual monomer. It is known that poor curing provides reduced quality of composite materials. Ī sufficient amount of light (energy) is necessary in order to achieve a thorough curing extending well into the depth of the material. It is recognized that shorter curing times will negatively affect material properties, but few studies have evaluated curing times below 10 s. While the recommended curing time for light curing composites previously was approximately 40 s, it is now advertised that the new LED lamps yield acceptable curing after only 5 s. This has led to a claim by some lamp manufacturers that very short curing times are sufficient in order to thoroughly cure a composite restoration. Advances in LED technology provide more efficient light emitters with higher energy output. Previously, quartz–tungsten–halogen (QTH) lamps were commonly used, whereas through the past decade or so, there has been a steady increase in the use of light emitting diode (LED) lamps. The restorative composites are mainly cured using a suitable curing device with visible (VIS), or sometimes ultraviolet (UV) and VIS radiation. The longevity and safe use of these materials are influenced by both mechanical and chemical properties, as well as the dentists’ technique and experience. 1Īs esthetic dentistry has become the ideal, and as the use of amalgam still is debated, restricted or even prohibited in some countries, composite materials now play a dominating role in modern restorative therapy. Dentists are recommended to use sufficient curing times even with high intensity LEDs to ensure adequate curing and minimize the risk of monomer leaching. This study demonstrates that reduced exposure time with high intensity LEDs can result in composite restorations with inferior curing depth and increased leaching of monomers.
![l.e.demetron ii l.e.demetron ii](https://www.henryscheindental.com/Products/1230838_600x600.jpg)
The measured surface properties of the materials, degree of conversion and wear resistance, were not affected by short curing times to the same extent.
![l.e.demetron ii l.e.demetron ii](https://www.researchgate.net/profile/Franklin-Garcia-Godoy-2/publication/254261013/figure/fig1/AS:601756551634961@1520481350354/The-emission-spectra-of-the-used-LCUs-HX-Hilux-601-DE-LEDemetron-GL-G-Light-and_Q320.jpg)
The results of this study show that short curing time with high-intensity LEDs may influence the bulk properties of the materials, resulting in lower curing depth and increased residual monomer content. The wear resistance after simulated tooth brushing, degree of conversion, curing depth, and amounts of residual monomers were measured after different curing times. Control samples were cured with a QTH-lamp (VCL 400, Kerr). The composites were Filtek Z250 (3M ESPE) and Tetric EvoCeram (Ivoclar Vivadent) and the LED curing devices were bluephase 16i (Ivoclar Vivadent), L.E.Demetron II (Kerr) and Mini L.E.D.
![l.e.demetron ii l.e.demetron ii](https://minio.scielo.br/documentstore/1807-3107/xdXHwzDHx7QPQsdNNFZ38JL/d0ca5fa7b7058295e818e0680a106dc370a4d80f.gif)
This study evaluates mechanical and chemical properties as a function of curing time of two commercial composite filling materials cured with three different LED lamps. The latest LED dental curing devices claim sufficient curing of restorative materials with short curing times.