title: Effect of pulse vs continuous micro-xenon irradiation on the shear bond strength of a light-cured orthodontic composite resin.
abstract: The aim of the study was to evaluate the effect of pulse vs. continuous irradiation on the shear bond strength of a conventional orthodontic composite resin cured with a micro-xenon light (Aurys, Degrè K, Schiltigheim, France). Ninety freshly extracted bovine permanent mandibular incisors were randomly assigned to one of six groups; each group consisting of 15 specimens. Three groups were exposed to continuous irradiation of micro-xenon light for 10, 5, and 2 s, respectively, and used as controls. The remaining three groups were exposed to pulse irradiation of the same light source for 10, 5, and 2 s, respectively. After 24 h, all samples were tested in a shear mode on an Instron Machine (Instron Corp., Canton, MA, USA). Analysis was made by ANOVA with Scheffé's test for comparisons. The chi-square test was used to determine significant differences in the Adhesive Remnant Index scores. The mean shear bond strength of the brackets continuously cured for 10 s was not statistically different from that of the brackets pulse-activated for the same curing time. Also, no statistically significant differences were found between both groups cured for 5 s. The group pulse-activated for 5 s, however, had a significantly lower mean shear bond strength than the control group cured for 10 s. Finally, the group pulse-activated for 2 s showed significantly lower bond strength values than all the other groups tested. Compared with continuous light curing, the micro-xenon pulse activation provides similar shear bond strength values, except when used for only 2 s; but despite lower performance characteristics, the shear bond strength may be clinically acceptable.
authors.affiliation: Department of Orthodontics, University of Pavia, Pavia, Italy.
authors.forename: Maria Francesca
authors.initials: MF
authors.lastname: Sfondrini
authors.forename: Vittorio
authors.initials: V
authors.lastname: Cacciafesta
authors.forename: Catherine
authors.initials: C
authors.lastname: Klersy
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Sfondrini
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000528:radiation effects*; D002417:Cattle; D016009:Chi-Square Distribution; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry / Q000528:radiation effects; D003799:Dental Stress Analysis; D066298:In Vitro Techniques; D007180:Incisor; D008029:Lighting / Q000295:instrumentation; D008334:Mandible; D008422:Materials Testing; D016910:Orthodontic Brackets; D011897:Random Allocation; D033081:Shear Strength; D013997:Time Factors; D014978:Xenon
chemical_list: D003188:Composite Resins; D003738:Dental Cements; C065742:Transbond; D014978:Xenon; D017438:Bisphenol A-Glycidyl Methacrylate