American Journal of Orthodontics and Dentofacial Orthopedics
Original articleQuantitative analysis of enamel on debonded orthodontic brackets
Section snippets
Material and methods
Ethics approval for the study was obtained from the Human Research Ethics Committee (number 1136902) of the University of Melbourne in Australia. Patients close to finishing fixed orthodontic treatment were recruited from 5 private orthodontic practices. Practices were invited to participate if they met the following inclusion criteria: (1) the clinicians in the practice used either metal In-Ovation R brackets (GAC International, Bohemia, NY) or ceramic In-Ovation C brackets (GAC
Results
The frequency of enamel presence on the bonding material on the bracket base pad is shown in Table I; there were differences between the groups (P = 0.001). Of the 486 brackets collected, 26.1% had detectable enamel on the base pad. The MEC group had a significantly lower incidence of tearouts compared with the CEC group (P = 0.015). There were significant differences in enamel damage when ceramic brackets attached with different materials were compared, with the CEC and CSEP groups having
Discussion
The force used to debond brackets can be applied to the bracket or to the bonding material, with failure occurring at the weakest interface or within the material with the weakest cohesive strength. In this study, clinicians applied a “lift-off” force to the wings of the metal brackets or force to the adhesive of the ceramic brackets. None of the metal brackets collected in this study fractured when removed. The BARI scores indicated failure predominantly at the bracket-adhesive interface (BARI
Conclusions
The following conclusions can be made from this study:
- 1.
Enamel damage regularly occurs during debonding and can be quite severe, although major damage is limited to a relatively few patients.
- 2.
Damage occurs more frequently with removal of ceramic brackets than with metal brackets.
- 3.
Ceramic brackets attached with RMGIC showed less damage (frequency and amount) than ceramic brackets attached with composite resin.
- 4.
Ceramic bracket fracture was greatest with 2-step etch-and-bond with composite resin, and
Acknowledgment
We thank Roger Curtain at the Bio21 Institute and Emily Szycman and David Thomas at the Melbourne Dental School.
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Cited by (0)
All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest, and none were reported.
Supported by a grant from the Australian Dental Research Foundation and the Australian Society of Orthodontists, Foundation for Research and Education.
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Deceased.