In vivo evaluation of a moisture-activated orthodontic adhesive: a comparative clinical trial

To evaluate and compare the clinical performance of a water-activated, ethyl-cyanoacrylate adhesive to a conventional composite resin. The null hypothesis tested was that there was no difference in bracket survival distribution, over a period of orthodontic treatment, for brackets bonded with either bonding agent.

Single center randomized controlled clinical study.

Twenty-five consecutive patients (15 females and 10 males) were selected and treated with fixed appliances in a university postgraduate orthodontic clinic. All teeth, but the molars, were bonded with twin stainless steel brackets (n = 429) using a split-mouth technique and random allocation of the two adhesives.

Bond failure rates during a period of 9 months were estimated for each adhesive system and the corresponding bracket survival curves were plotted using the Kaplan-Meier product-limit estimate. Bracket survival distributions with respect to adhesive material, tooth location, investigator, and bond failure interface were then compared by means of a log-rank test. Bond failure interface was determined using the Adhesive Remnant Index (ARI).

The water-activated bonding material recorded a significantly higher bond failure (22.4%) than the composite resin (5.1%). There were also statistically significant differences in bracket survival distributions between the two adhesives (log-rank test: p < 0.001). Premolars exhibited higher bond failure rates than incisors and canines (p < 0001). The predominant mode of failure was within the bonding material.

Further investigations focused on the improvement of the physical and mechanical properties of the water-activated bonding system are needed to make it a reliable alternative adhesive for the direct bonding of orthodontic brackets.