Long-term clinical evaluation of bracket failure with a self-etching primer: a randomized controlled trial

OBJECTIVE: A long-term comparison of the failure rates of orthodontic brackets bonded with either a self-etching primer (SEP) or conventional etch and primer (AE). DESIGN: Prospective randomized controlled clinical trial. SETTING: UK district general hospital with one operator, 2003-6. PARTICIPANTS: Hospital waiting list patients needing fixed appliances (n=60). METHOD: Experimental (SEP) group patients (n=30) received pre-adjusted edgewise brackets (n=438) bonded with Transbond Plus following manufacturer's instructions. Control (AE) group patients (n=30, brackets n=433) were bonded using a 15-second conventional etch and primer (Transbond XT). In both groups brackets were light-cured for 20 seconds. First-time bond failures were recorded with the time of failure. Bracket bonding time was recorded. All patients were followed to the end or discontinuation of treatment. RESULTS: Bracket failure rates: SEP=4.8%, AE=3.5%, P=0.793. Mean placement time per bracket (seconds): SEP=75.5 (+/-6.7; 95% CI=72.9, 78.0), AE=97.7 (+/-9.1; 95% CI=94.3, 101.2) P=0.000. CONCLUSION: There was no difference in the failure rates of brackets bonded with either Transbond Plus SEP or conventional AE using Transbond XT paste. Bonding with SEP was significantly faster than using conventional AE.