Clinical evaluation of the failure rates of metallic brackets.
OBJECTIVE
The aim of this study was to evaluate in vivo the bonding of metallic orthodontic brackets with different adhesive systems.


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.
Department of Pediatric Clinic, Preventive and Community Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil. fabioromano@forp.usp.br
Fábio Lourenço
FL
Romano
Américo Bortolazzo
AB
Correr
Lourenço
L
Correr-Sobrinho
Maria Beatriz Borges de Araújo
MB
Magnani
Antônio Carlos de Oliveira
AC
Ruellas
D017677:Age Distribution; D000704:Analysis of Variance; D002648:Child; D055117:Curing Lights, Dental; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry*; D019232:Dental Restoration Failure; D004868:Equipment Failure; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D016910:Orthodontic Brackets; D019279:Resin Cements / Q000737:chemistry*; D017678:Sex Distribution; D013997:Time Factors
D003738:Dental Cements; D019279:Resin Cements; C477790:Transbond XT