Effect of using a new cyanoacrylate adhesive on the shear bond strength of orthodontic brackets

During bonding of orthodontic brackets to enamel, conventional adhesive systems use three different agents: an enamel conditioner, a primer solution, and an adhesive resin. A unique characteristic of some new bonding systems is that they need neither a priming agent nor a curing light to bond brackets. Such an approach should be more cost-effective for the clinician and indirectly also for the patient. The purpose of this study was to determine the effects of using a cyanoacrylate adhesive on the shear bond strength of orthodontic brackets and on the bracket/adhesive failure mode. The brackets were bonded to extracted human teeth according to one of two protocols. Group 1: Teeth were etched with 37% phosphoric acid. After applying the primer, the brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif) and were light-cured for 20 seconds. Group 2: Teeth were etched with 35% phosphoric acid. The brackets were then bonded with Smartbond (Gestenco International, Göthenburg, Sweden). The present in vitro findings indicated that the use of the cyanoacrylate adhesive to bond orthodontic brackets to the enamel surface did not result in a significantly different (P = .24) shear bond force (mean = 5.8 +/- 2.4 MPa) as compared to the control group (mean = 5.2 +/- 2.9 MPa). The comparison of the Adhesive Remnant Index scores indicated that there was significantly (P = .006) less residual adhesive remaining on the tooth with the cyanoacrylate than on the tooth with the conventional adhesive system. In conclusion, the new adhesive has the potential to be used to bond orthodontic brackets while reducing the total bonding time.