Clinical evaluation of the failure rates of metallic brackets

Objectives

The aim of this study was to evaluate in vivo the bonding ofmetallic orthodontic brackets with different adhesive systems.

Material and Methods

Twenty patients (10.5-15.1 years old) who had sought corrective orthodontictreatment at a University Orthodontic Clinic were evaluated. Brackets were bondedfrom the right second premolar to the left second premolar in the upper and lowerarches using: Orthodontic Concise, conventional Transbond XT, Transbond XT withoutprimer, and Transbond XT associated with Transbond Plus Self-etching Primer(TPSEP). The 4 adhesive systems were used in all patients using a split-mouthdesign; each adhesive system was used in one quadrant of each dental arch, so thateach group of 5 patients received the same bonding sequence. Initial archwireswere inserted 1 week after bracket bonding. The number of bracket failures foreach adhesive system was quantified over a 6-month period.

Results

The number of debonded brackets was: 8- Orthodontic Concise, 2- conventionalTransbond XT, 9- Transbond XT without primer, and 1- Transbond XT + TPSEP. Byusing the Kaplan-Meier methods, statistically significant differences were foundbetween the materials (p=0.0198), and the Logrank test identified thesedifferences. Conventional Transbond XT and Transbond XT + TPSEP adhesive systemswere statistically superior to Orthodontic Concise and Transbond XT without primer(p<0.05). There was no statistically significant difference between the dentalarches (upper and lower), between the dental arch sides (right and left), andamong the quadrants.

Conclusions

The largest number of bracket failures occurred with Orthodontic Concise andTransbond XT without primer systems and few bracket failures occurred withconventional Transbond XT and Transbond XT+TPSEP. More bracket failures wereobserved in the posterior region compared with the anterior region.