Shear bond strength of metallic brackets: influence of saliva contamination

Abstract

Objective:To evaluate the influence of saliva contamination on shear bond strength and the bond failure pattern of 3 adhesive systems (Transbond XT, AdheSE and Xeno III) on orthodontic metallic brackets bonded to human enamel.Material and Methods:Seventy-two permanent human molars were cut longitudinally in a mesiodistal direction, producing seventy-two specimens randomly divided into six groups. Each system was tested under 2 different enamel conditions: no contamination and contaminated with saliva. In T, A and X groups, the adhesive systems were applied to the enamel surface in accordance with manufacturer's instructions. In TS, AS and XS groups, saliva was applied to enamel surface followed by adhesive system application. The samples were stored in distilled water at 37°C for 24 h, and then tested for shear bond strength in a universal testing machine (Emic, DL 2000) running at a crosshead speed of 1 mm/min. After bond failure, the enamel surfaces were observed under an optical microscope at 40x magnification.Results:The control and contaminated groups showed no significant difference in shear bond strength for the same adhesive system. However, shear bond strength of T group (17.03±4.91) was significantly higher than that of AS (8.58±1.73) and XS (10.39±4.06) groups (p<0.05). Regarding the bond failure pattern, TS group had significantly higher scores of no adhesive remaining on the tooth in the bonding area than other groups considering the adhesive remnant index (ARI) used to evaluate the amount of adhesive left on the enamel.Conclusion:Saliva contamination showed little influence on the 24-h shear bond strength of orthodontic brackets.

Blood contamination effect on shear bond strength of an orthodontic hydrophilic resin

“…Those in vitro characteristics support the clinical practice through the shear bond strength and ARI scores 23 . The correlation between in vitro and in vivo adhesive/resin interfaces and bond strength tests has been shown elsewhere 25 .…”

Effect of methacrylated-based antibacterial monomer on orthodontic adhesive system properties

“…The sample size calculation for each assay was based on previous studies. 19,20 Comparisons of antibacterial activity, degree of conversion, percentage of variation of Knoop hardness, and shear bond strength data were performed with 1-way analysis of variance and Tukey tests. Comparisons of initial and final Knoop hardness values were performed with paired t tests for each group.…”

Efeito da contaminação por saliva na resistência adesiva de braquetes cerâmicos utilizando uma resina ortodôntica hidrofílica

“…Os sistemas adesivos ortodônticos convencionais foram desenvolvidos para serem utilizados em ambiente sem contaminação por umidade, proporcionando uma resistência adesiva apropriada 10,11 . Embora alguns estudos [13][14][15] tenham mostrado que a contaminação por umidade é um fator importante na diminuição da RA de braquetes ortodônticos, outros estudos não encontraram diferença na RA frente à contaminação [16][17][18] . Estes resultados diferentes podem ser atribuídos aos diferentes sistemas adesivos utilizados nos estudos.…”

“…Visando melhorar a colagem de braquetes e acessórios ortodônticos em meio úmido, a indústria odontológica vem desenvolvendo novos adesivos hidrofílicos para que, além de diminuírem os passos clínicos na rotina profissional, sejam resistentes às forças ortodônticas e de mastigação 19 . Estes resultados concordam com outros estudos [16][17][18]21 , comprovando que estes materiais apresentam adequada performance, mesmo quando há contaminação. Estes resultados proporcionam segurança ao clínico, já que o ambiente bucal é extremamente úmido e, mesmo com cuidados de controle da saliva, pode ocorrer esta contaminação durante o procedimento de colagem de braquetes.…”