title: Effect of light-emitting diode on bond strength of orthodontic brackets.
abstract: The aim of this study was to evaluate the effect of light-emitting diode (LED) light curing on shear bond strength (SBS) of orthodontic brackets bonded to teeth. Light exposure of 40 seconds from a conventional halogen-based light-curing unit was used as a control. Eighty human premolars were divided into four groups of 20 each. Brackets were bonded to acid-etched teeth with Transbond XT light-cured adhesive. In the first group, the adhesive was light cured for 40 seconds with a conventional halogen unit (XL3000, 3M). In the other three groups, adhesive was cured with a commercial LED unit (Elipar FreeLight, 3M ESPE) for 10, 20, or 40 seconds. SBS of brackets was measured on a universal testing machine and recorded in megapascals. Adhesive remnant index (ARI) scores were determined after failure of brackets. Data were analyzed using analysis of variance and chi-square tests. No statistically significant differences were found among the SBS values of halogen-based light-cured (13.1 +/- 3.1 MPa) and 20- and 40-second LED-cured (13.9 +/- 4.8 MPa and 12.7 +/- 5.1 MPa) specimens (P > .05). However, 10 seconds of LED curing yielded significantly lower SBS (P < .05). No statistically significant differences were found between the ARI scores among groups. The results of this study are promising for the orthodontic application of LED-curing units, but further compatibility and physical characteristic studies of various orthodontic adhesives and clinical trials should be performed before validation.
authors.affiliation: Department of Orthodontics, Faculty of Dentistry, Selçuk University, Konya, Turkey. susumez@hotmail.com
authors.forename: Serdar
authors.initials: S
authors.lastname: Uşümez
authors.forename: Tamer
authors.initials: T
authors.lastname: Büyükyilmaz
authors.forename: Ali Ihya
authors.initials: AI
authors.lastname: Karaman
mesh_terms: D001840:Dental Bonding; D017005:Dental Debonding; D003748:Dental Equipment; D003799:Dental Stress Analysis; D006219:Halogens; D006801:Humans; D008027:Light; D015394:Molecular Structure; D016910:Orthodontic Brackets; D044367:Phase Transition; D019279:Resin Cements / Q000528:radiation effects*; D033081:Shear Strength; D013193:Stainless Steel; D014159:Transducers
chemical_list: D006219:Halogens; D019279:Resin Cements; C477790:Transbond XT; D013193:Stainless Steel