Clinical evaluation of the failure rates of metallic brackets

objectives: the aim of this study was to evaluate in vivo the bonding of metallic orthodontic brackets with different adhesive systems. material and methods: twenty patients (10.5-15.1 years old) who had sought corrective orthodontic treatment at a university orthodontic clinic were evaluated. brackets were bonded from the right second premolar to the left second premolar in the upper and lower arches using: orthodontic concise, conventional transbond xt, transbond xt without primer, and transbond xt associated with transbond plus self-etching primer (tpsep). the 4 adhesive systems were used in all patients using a split-mouth design; each adhesive system was used in one quadrant of each dental arch, so that each group of 5 patients received the same bonding sequence. initial archwires were inserted 1 week after bracket bonding. the number of bracket failures for each adhesive system was quantified over a 6-month period. results: the number of debonded brackets was: 8- orthodontic concise, 2- conventional transbond xt, 9- transbond xt without primer, and 1- transbond xt + tpsep. by using the kaplan-meier methods, statistically significant differences were found between the materials (p=0.0198), and the logrank test identified these differences. conventional transbond xt and transbond xt + tpsep adhesive systems were statistically superior to orthodontic concise and transbond xt without primer (p<0.05). there was no statistically significant difference between the dental arches (upper and lower), between the dental arch sides (right and left), and among the quadrants. conclusions: the largest number of bracket failures occurred with orthodontic concise and transbond xt without primer systems and few bracket failures occurred with conventional transbond xt and transbond xt+tpsep. more bracket failures were observed in the posterior region compared with the anterior region.