Shear bond strength differences of types of maxillary deciduous and permanent teeth used as anchor teeth.
OBJECTIVE
To compare the bond strengths of identical orthodontic brackets bonded to maxillary deciduous and permanent teeth, which were used as anchor teeth in sectional edgewise appliance therapy, and to evaluate the modes of bracket/adhesive failure.


METHODS
A total of 28 human maxillary teeth were divided into four groups by tooth type: permanent first premolars (group I), permanent second premolars (group II), deciduous canines (group III), and deciduous second molars (group IV). Each group consisted of seven teeth. Metal premolar brackets were bonded to these specimens using an acid-etching adhesive system. Shear bond strengths were measured using a universal testing machine, and the bracket/ adhesive failure modes were evaluated with the Adhesive Remnant Index.


RESULTS
The shear strengths of the bonds on the deciduous canines and second molars were significantly lower than those on the permanent first and/or second premolars. There were no significant differences in shear bond strength between the permanent first and second premolars, and between the deciduous canines and second molars. The shear bond strengths of all four tooth types were higher than the clinically sufficient range of strengths from 6 to 8 MPa. Bond failure at the enamel-adhesive interface occurred more frequently in the deciduous second molars than in the permanent first premolars.


CONCLUSIONS
There were significant differences in shear bond strength among different permanent and deciduous tooth types, but deciduous teeth could be used as anchor teeth in orthodontic treatment with sectional edgewise appliances.
Endo
Toshiya
T
Department of Orthodontics, The Nippon Dental University Niigata Hospital, 1-8 Hamaura-cho, Niigata, Niigata 951-8580, Japan. endoto@ngt.ndu.ac.jp
Yoshino
Sugako
S
Shinkai
Koichi
K
Ozoe
Rieko
R
Shimada
Michiyuki
M
Katoh
Yoshiroh
Y
Shimooka
Shohachi
S
D000704:Analysis of Variance; D001641:Bicuspid; D003481:Cuspid; D001840:Dental Bonding / Q000379:methods*; D003743:Dental Enamel / Q000648:ultrastructure; D006801:Humans; D008963:Molar; D016910:Orthodontic Brackets; D033081:Shear Strength; D018709:Statistics, Nonparametric; D014094:Tooth, Deciduous