title: Comparison of shear bond strengths of orthodontic brackets bonded to deciduous and permanent teeth.
abstract: BACKGROUND
  This study was conducted (1) to compare the bond strengths of identical orthodontic brackets bonded to deciduous and permanent teeth with either of 2 primer/adhesive systems and (2) to evaluate the modes of bracket/adhesive failure.
  
  
  METHODS
  Thirty-four permanent teeth and 34 deciduous teeth were collected. To these freshly extracted teeth, metal brackets were bonded with 2 primer/adhesive systems. These specimens were divided into 4 groups. In group I, consisting of 17 permanent teeth, the brackets were bonded with an acid-etching adhesive system; in group II, the self-etching adhesive system was used for bonding the brackets to 17 permanent teeth; in group III, consisting of 17 deciduous teeth, the acid-etching adhesive system was used; and in group IV, the self-etching adhesive system was used for bonding the brackets to 17 deciduous teeth. Shear bond strength was measured with a universal testing machine, and the mode of bracket/adhesive failure was determined according to the adhesive remnant index.
  
  
  RESULTS
  The shear bond strengths of all 4 groups exceeded what is believed to be clinically sufficient strength of 6 to 8 MPa. Whether deciduous or permanent teeth, there were no significant differences in shear bond strength between the acid-etching and self-etching adhesive systems. The shear bond strengths of the brackets bonded to the deciduous teeth with either adhesive system were lower than those to the permanent teeth. Bond failure occurred at the enamel-adhesive interface more frequently in the self-etching adhesive system than in the acid-etching adhesive system.
  
  
  CONCLUSIONS
  Bond strengths of brackets were lower with deciduous teeth but were high enough for clinical purposes.
authors.affiliation: Orthodontic Dentistry, Nippon Dental University, Niigata Hospital, Niigata, Japan. endoto@ngt.ndu.ac.jp
authors.forename: Toshiya
authors.initials: T
authors.lastname: Endo
authors.forename: Rieko
authors.initials: R
authors.lastname: Ozoe
authors.forename: Koichi
authors.initials: K
authors.lastname: Shinkai
authors.forename: Junko
authors.initials: J
authors.lastname: Shimomura
authors.forename: Yoshiroh
authors.initials: Y
authors.lastname: Katoh
authors.forename: Shohachi
authors.initials: S
authors.lastname: Shimooka
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry* / Q000627:therapeutic use; D001840:Dental Bonding / Q000379:methods*; D003743:Dental Enamel / Q000187:drug effects*; D045662:Dental Etching / Q000379:methods; D003799:Dental Stress Analysis; D019229:Dentition, Permanent; D006801:Humans; D066298:In Vitro Techniques; D008334:Mandible; D008437:Maxilla; D016910:Orthodontic Brackets; D033081:Shear Strength; D018709:Statistics, Nonparametric; D014094:Tooth, Deciduous
chemical_list: D003188:Composite Resins