Tensile bond force of glass ionomer cements in direct bonding of orthodontic brackets: an in vitro comparative study.

Tensile bond force of three glass ionomers was evaluated in vitro. Ketac-Cem and Aqua-Cem, two conventional cements, and light-cured Vitrabond were used in this study. The results were then compared with the values obtained for a composite resin (Concise) by means of the Mann-Whitney two-sample rank test adjusted for ties. The composite resin had a significantly higher bond force (152.5 N) than any of the other adhesives (5.5 to 27.53 N) used. Tensile bond strength was also calculated and the failure bond site investigated on the enamel surface was evaluated. The composite resin and the two conventional glass ionomers used had high cement percentages (86% to 62%) adhering to the enamel surface. Cement remaining on enamel was lower (20%) for the light-cured glass ionomer. It was concluded that the in vitro bond force of Vitrabond might be adequate for orthodontic bracket bonding.