An ex vivo study of self-, light-, and dual-cured composites for orthodontic bonding.

It was postulated that using a dual-cured composite to bond orthodontic brackets could result in bond strengths comparable with those of chemically-activated materials and higher than those for light-activated materials. The shear bond strength of four composite resins used to attach mesh-backed orthodontic brackets was measured at 24 hours and following mechanical insult in the ball-mill. Analysis of variance and an SNK range test showed that at 24 hours Dual-cured Porcelite gave a significantly higher mean bond strength than the other materials (P < 0.05). However, following ball-milling the mean bond strength for Right-on was apparently significantly higher than that of the other materials. (P < 0.05). In this study, the mode of bond failure is also analysed and the use of Weibull analysis in bond strength testing is described.