T. Eliades et al., FAILURE MODE ANALYSIS OF CERAMIC BRACKETS BONDED TO ENAMEL, American journal of orthodontics and dentofacial orthopedics, 104(1), 1993, pp. 21-26
The purpose of this study was to evaluate in vitro the failure pattern
of ceramic brackets bonded to enamel with a light-cured orthodontic a
dhesive. Five types of ceramic brackets and 125 incisors were used in
the study. The brackets were bonded onto enamel with a light-cured ort
hodontic adhesive. After 1 week storage and thermal cycling, the sampl
es were debonded by one operator according to the individual technique
for each bracket group proposed by each manufacturer. The fracture su
rfaces were examined under a stereomicroscope to reveal the type of fa
ilures. The effect of the debonding procedure on enamel structure was
significantly affected by the various bonding mechanisms of the bracke
t bases. Cohesive enamel fractures were detected from brackets that pr
ovided a bonding mechanism of micromechanical retention and chemical a
dhesion. The brackets that combined mechanical retention and chemical
adhesion, presented both cohesive resin fractures and fractures locate
d at the bracket resin or the resin enamel interface. The higher frequ
ency of cohesive bracket fractures was obtained from a monocrystalline
bracket.