title: Surface microhardness of a nanofilled resin composite: a comparison of a tungsten halogen and a light-emitting diode light curing unit, in vitro.
abstract: Surface microhardness numbers (VHN) have been measured and compared for disk specimens (thickness 1.5 mm) of a commercial nanofilled resin composite cured using a range of exposure times with a quartz tungsten halogen (QTH) and light-emitting diode (LED) light-curing unit (LCU), respectively. Each LCU requires different minimum exposure times to optimise VHN with respect to the internal controls but yield bottom surface/top surface VHN ratios > 0.95 with these optimised exposure times. Both LCUs produce comparable VHNs for the top surfaces at short exposure times but the QTH LCU requires increased exposure time for comparable results with the bottom surfaces. Overall, the LCUs are capable of producing comparable VHN numbers and VHN ratios within the parameters investigated.
authors.affiliation: University Dental School & Hospital, Wilton, Cork, Ireland.
authors.forename: Mary
authors.initials: M
authors.lastname: O'Reilly
authors.forename: Noel J
authors.initials: NJ
authors.lastname: Ray
authors.forename: Robert J
authors.initials: RJ
authors.lastname: McConnell
authors.forename: Ailish
authors.initials: A
authors.lastname: Hannigan
mesh_terms: D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003764:Dental Materials / Q000737:chemistry* / Q000528:radiation effects; D006219:Halogens; D006244:Hardness; D008027:Light; D053761:Nanocomposites / Q000737:chemistry* / Q000528:radiation effects; D013499:Surface Properties; D013997:Time Factors
chemical_list: C520091:CeramX; D003188:Composite Resins; D003764:Dental Materials; D006219:Halogens