title: Effect of etching time and light source on the bond strength of metallic brackets to ceramic.
abstract: This study evaluated the bond strength of brackets to ceramic testing different etching times and light sources for photo-activation of the bonding agent. Cylinders of feldspathic ceramic were etched with 10% hydrofluoric acid for 20 or 60 s. After application of silane on the ceramic surface, metallic brackets were bonded to the cylinders using Transbond XT (3M Unitek). The specimens for each etching time were assigned to 4 groups (n=15), according to the light source: XL2500 halogen light, UltraLume 5 LED, AccuCure 3000 argon laser, and Apollo 95E plasma arc. Light-activation was carried out with total exposure times of 40, 40, 20 and 12 s, respectively. Shear strength testing was carried out after 24 h. The adhesive remnant index (ARI) was evaluated under magnification. Data were subjected to two-way ANOVA and Tukey's test (α=0.05). Specimens etched for 20 s presented significantly lower bond strength (p<0.05) compared with those etched for 60 s. No significant differences (p>0.05) were detected among the light sources. The ARI showed a predominance of scores 0 in all groups, with an increase in scores 1, 2 and 3 for the 60 s time. In conclusion, only the etching time had significant influence on the bond strength of brackets to ceramic.
authors.affiliation: Department of Orthodontics, Dental School, São Leopoldo Mandic Research Center, Campinas, SP, Brazil.
authors.forename: Paulo Roberto Amaral
authors.initials: PR
authors.lastname: Gonçalves
authors.forename: Rafael Ratto de
authors.initials: RR
authors.lastname: Moraes
authors.forename: Ana Rosa
authors.initials: AR
authors.lastname: Costa
authors.forename: Américo Bortolazzo
authors.initials: AB
authors.lastname: Correr
authors.forename: Paulo Roberto Aranha
authors.initials: PR
authors.lastname: Nouer
authors.forename: Mário Alexandre Coelho
authors.initials: MA
authors.lastname: Sinhoreti
authors.forename: Lourenço
authors.initials: L
authors.lastname: Correr-Sobrinho
mesh_terms: D000268:Adhesiveness; D000538:Aluminum Silicates / Q000737:chemistry; D055117:Curing Lights, Dental / Q000145:classification*; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods*; D003776:Dental Porcelain / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D008422:Materials Testing; D016910:Orthodontic Brackets; D055668:Photochemical Processes; D058105:Polymerization; D017680:Potassium Compounds / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014070:Tooth / Q000033:anatomy & histology
chemical_list: D000538:Aluminum Silicates; D003722:Dental Alloys; D017680:Potassium Compounds; D019279:Resin Cements; D012821:Silanes; C477790:Transbond XT; D003776:Dental Porcelain; C016447:feldspar; D013193:Stainless Steel; D006858:Hydrofluoric Acid