Effect of activation mode on shear bond strength of metallic brackets.
The aim of this study was to evaluate the shear bond strength (SBS) of metallic orthodontic brackets bonded to bovine teeth using light-activated or chemically activated composite resins. One hundred and twenty bovine mandibular incisors were divided into 6 groups (n=20), according to the bonding materials: Transbond XT (T); Enforce Dual (ED); Enforce chemical (EC); Enforce Light-activated (EL); Concise Orthodontic (C); and RelyX Unicem Capsule (UN). Metallic brackets were positioned and firmly bonded to the teeth. Light-activation for T, ED, EL and UN was carried out with four exposures on each side of the bracket with 20 s total exposure times using XL2500 (3M ESPE). EC and C were chemically cured. Next, all specimens were stored in deionized water at 37 °C for 24 h. The shear bond strength was carried out at a crosshead speed of 1.0 mm/min. Data were subjected to one-way ANOVA and Tukey's test (α=0.05). The adhesive remnant index (ARI) was evaluated at 8× magnification. C (17.72 ± 4.45) presented significantly higher SBS means (in MPa) than the other groups (p<0.05), followed by EC (11.97 ± 5.77) and ED (10.57 ± 1.32). EL (5.39 ± 1.06) and UN (4.32 ± 1.98) showed the lowest SBS means, while T (9.09 ± 2.56) showed intermediate values. For ARI, there was a predominance of score 0 for EC, C and UN, and score 3 for T, ED and EL. In conclusion, the activation mode influenced the SBS.
Department of Restorative Dentistry, Dental Materials Division, Piracicaba School of Dentistry, UNICAMP - University of Campinas, PiracicabaSP, Brazil.
Américo Bortolazzo
AB
Correr
Department of Restorative Dentistry, Dental Materials Division, Piracicaba School of Dentistry, UNICAMP - University of Campinas, PiracicabaSP, Brazil.
Ana Rosa
AR
Costa
Department of Orthodontics, Graduate Program in Orthodontics, UNIARARAS - University of Araras, ArarasSP, Brazil.
Adriana Simoni
AS
Lucato
Department of Orthodontics, Graduate Program in Orthodontics, UNIARARAS - University of Araras, ArarasSP, Brazil.
Silvia Amélia
SA
Vedovello
Department of Orthodontics, Graduate Program in Orthodontics, UNIARARAS - University of Araras, ArarasSP, Brazil.
Heloísa Cristina
HC
Valdrighi
Department of Orthodontics, Graduate Program in Orthodontics, UNIARARAS - University of Araras, ArarasSP, Brazil.
Mário
M
Vedovello Filho
Department of Restorative Dentistry, Dental Materials Division, Piracicaba School of Dentistry, UNICAMP - University of Campinas, PiracicabaSP, Brazil.
Lourenço
L
Correr-Sobrinho
D008422:Materials Testing; D008670:Metals; D016910:Orthodontic Brackets; D033081:Shear Strength
D008670:Metals