title: Shear bond strength of orthodontic brackets bonded to deciduous teeth with different etching times.
abstract: OBJECTIVE
  This was to compare shear bond strength (SBS) of brackets bonded to deciduous teeth with that of permanent teeth, to evaluate  the effect of increasing etching time on the SBS of brackets bonded to deciduous teeth and to evaluate the modes of bond failure after de-bonding.
  
  
  METHODS
  ex vivo  study.
  
  
  METHODS
  A total of 120 freshly extracted human maxillary teeth were divided into six groups of 20 teeth each as follows: Group 1, permanent canines with 15-second etching time; Group 2, first premolars with 15-second etching time; Group 3, deciduous canines with 15-second etching time; Group 4, deciduous first molars with 15-second etching time; Group 5, deciduous canines with 30-second etching time; Group 6, deciduous first molars with 30-second etching time. After bonding, all specimens were thermocycled from 5 °C to 55 °C and back to 5 °C 500 times. The modified ARI was used to determine the mode of bond failure.
  
  
  METHODS
  Comparison between groups was performed using Univariate General Linear Model (UGLM) and chi-squared tests.
  
  
  RESULTS
  SBS for permanent and deciduous teeth etched for 15 seconds averaged 106.60 ± 34.69 N and 96.90 ± 28.51 N, respectively. SBS for deciduous teeth etched for 15 seconds (91.90 ± 32.90 N and 101.80 ± 23.12 N for canines and molars respectively) and 30 seconds (110.40 ± 30.11 N and 94.20 ± 25.74 N for canines and molars, respectively). No significant differences were recorded between the different groups. Bond failure at the enamel-adhesive interface occurred more frequently in the deciduous teeth groups, while failure at bracket-adhesive interface occurred more frequently in the permanent teeth group.
  
  
  CONCLUSIONS
  SBS of brackets bonded to deciduous teeth was comparable to that of permanent teeth.
authors.affiliation: Department of Preventive Dentistry, Jordan University of Science and Technology, Irbid, Jordan. elham@just.edu.jo
authors.forename: E S J
authors.initials: ES
authors.lastname: Abu Alhaija
authors.forename: S M
authors.initials: SM
authors.lastname: Irshaid
authors.forename: A M S
authors.initials: AM
authors.lastname: Alwahadni
mesh_terms: D016009:Chi-Square Distribution; D003481:Cuspid; D001840:Dental Bonding; D045662:Dental Etching / Q000379:methods*; D003799:Dental Stress Analysis; D019229:Dentition, Permanent; D006801:Humans; D016014:Linear Models; D008963:Molar; D016910:Orthodontic Brackets; D033081:Shear Strength; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013997:Time Factors; D014094:Tooth, Deciduous