title: Survival analysis of brackets and tubes: A twelve-month assessment.
abstract: OBJECTIVE
  To compare the clinical performance of brackets bonded to anterior and posterior teeth, including second molars.
  
  
  METHODS
  One operator, using the straight-wire technique, bonded metallic brackets to the teeth of 127 consecutive patients. All patients were observed for 12 months during their regular orthodontic appointments. Bracket failures were recorded and summarized for statistical analysis. The Cox proportional hazards regression analysis was performed to evaluate bracket failure rates.
  
  
  RESULTS
  Statistically significant differences in survival rates were observed between molar tubes and anterior brackets (P < .05). Twelve-month failure rates of incisor, canine, premolar, and molar brackets were 3.6, 1.6, 4.8, and 11.6%, respectively. The first and second molar did not show significant difference in bond failure. Young patients (age <18 years) showed a higher failure rate than old patients (≥18 years).
  
  
  CONCLUSIONS
  Brackets directly bonded to the buccal surfaces of molars failed significantly more often than those directly bonded to anterior teeth or premolars, but showed acceptable failure rate especially in adult patients. Bonding on second molars seems to be as reliable as bonding on the first molars.
authors.affiliation: a  Adjunct Associate Professor, Department of Orthodontics, Dental Research Institute and School of Dentistry, Seoul National University; Private practice, Seoul, Korea.
authors.forename: Min-Ho
authors.initials: MH
authors.lastname: Jung
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001641:Bicuspid; D015331:Cohort Studies; D055117:Curing Lights, Dental / Q000145:classification; D003481:Cuspid; D003722:Dental Alloys / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods; D004868:Equipment Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007180:Incisor; D008297:Male; D008963:Molar; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets / Q000706:statistics & numerical data*; D010756:Phosphoric Acids / Q000737:chemistry; D016016:Proportional Hazards Models; D011446:Prospective Studies; D019279:Resin Cements / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D003722:Dental Alloys; D010756:Phosphoric Acids; D019279:Resin Cements; C477790:Transbond XT; D013193:Stainless Steel; C030242:phosphoric acid
keywords: Bonding; Bracket failure; Molar tube