title: Evaluation of the debonding characteristics of 2 ceramic brackets: an in vitro study.
abstract: The objectives of this study were to evaluate and compare the shear bond strengths and bond failure locations of 2 currently available orthodontic ceramic brackets. Forty polycrystalline ceramic brackets (Clarity, 3M Unitek, Monrovia, Calif) and 40 monocrystalline ceramic brackets (Inspire, Ormco, Orange, Calif) were bonded to 80 extracted premolars with the same bonding system. All bonded specimens were placed in distilled water for 42 hours at 37 degrees C followed by thermal cycling for 700 complete cycles. Forty ceramic brackets, 20 of each type, were tested on a universal testing machine to determine the shear force levels required to debond them. Forty ceramic brackets were removed with the debonding pliers recommended by the manufacturers. All teeth were examined under an optical microscope, and the adhesive remnant index was used to assess the bond failure locations. The mean shear bond strength of the Clarity brackets was 21.67 +/- 5.19 MPa, and the mean shear bond strength of the Inspire brackets was 20.32 +/- 8 MPa. The mean shear bond strengths of both brackets were higher than those considered clinically optimal. Most of the brackets (85% of Clarity and 75% of Inspire) tested on the machine failed at the bracket-adhesive interface. One premolar bonded with an Inspire bracket had enamel fracture upon debonding. Most of the brackets (90% of Clarity and 95% of Inspire) debonded with pliers failed at the bracket-adhesive interface. No enamel damage was evident in any specimen when the brackets were removed with the appropriate pliers. The results indicate that the safest way to remove ceramic brackets with respect to reducing the chance of enamel damage is to use the debonding technique specifically designed for each.
authors.affiliation: Department of Orthodontics, University of Alabama at Birmingham, Birmingham, AL, USA. linatheodorakopoulou@yahoo.com
authors.forename: Lina P
authors.initials: LP
authors.lastname: Theodorakopoulou
authors.forename: P Lionel
authors.initials: PL
authors.lastname: Sadowsky
authors.forename: Alex
authors.initials: A
authors.lastname: Jacobson
authors.forename: William
authors.initials: W
authors.lastname: Lacefield
mesh_terms: D001641:Bicuspid; D002516:Ceramics / Q000737:chemistry*; D016009:Chi-Square Distribution; D003461:Crystallography; D001840:Dental Bonding; D017005:Dental Debonding / Q000295:instrumentation; D003743:Dental Enamel / Q000293:injuries; D003799:Dental Stress Analysis / Q000295:instrumentation; D004868:Equipment Failure; D006801:Humans; D008422:Materials Testing; D016910:Orthodontic Brackets; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D019279:Resin Cements; C477790:Transbond XT; D014867:Water