title: Third-generation vs a second-generation LED curing light: effect on Knoop microhardness.
abstract: Third-generation light-emitting diode (LED) curing lights use several different types of LEDs within the light to deliver a broader spectral output compared with the narrower spectral output of second-generation curing lights. This study determined the benefits of this broader spectral output. A third-generation LED curing light was modified so that the 4 peripheral LEDs, which provide the lower wavelengths, could be turned on or off, allowing the light to be used as a third- or a second-generation LED curing light. Twelve composites of A2 and lighter shades were packed into molds 2 mm deep with an internal diameter of 12 mm, and then irradiated for 20 seconds. A laboratory-grade spectroradiometer was used to ensure that all the specimens received the same irradiance and total energy (16.82 J/cm2) from the curing light in both the second- and third-generation modes. The results showed the benefits of using a broader spectrum third-generation LED curing light. This light produced composites that were as hard as when the narrower spectrum second-generation LED curing light was used (P < or = .01). In 7 of the 12 resin composites, the top surface was harder when the third-generation LED curing light was used (P < or = .01).
authors.affiliation: Department of Dental Clinical Sciences, Dalhousie University, Halifax, Canada.
authors.forename: Richard B T
authors.initials: RB
authors.lastname: Price
authors.forename: Corey A
authors.initials: CA
authors.lastname: Felix
authors.forename: Pantelis
authors.initials: P
authors.lastname: Andreou
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D003764:Dental Materials / Q000737:chemistry / Q000528:radiation effects*; D004867:Equipment Design; D006244:Hardness; D006801:Humans; D008027:Light; D008029:Lighting / Q000295:instrumentation*; D011829:Radiation Dosage; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013997:Time Factors
chemical_list: C485363:Aelite LS; C098721:Aelitefil; D003188:Composite Resins; D003764:Dental Materials; C474035:Filtek Supreme; C478050:Heliomolar HB; D012821:Silanes; C121818:Tetric ceram; C515948:Vit-l-escence Trans Ice; C111840:flowable hybrid composite; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide