title: Comparison of debonding characteristics of metal and ceramic orthodontic brackets to enamel: an in-vitro study.
abstract: BACKGROUND
  The objectives of this study were to compare the debonding strengths of 1 metal and 2 types of ceramic orthodontic brackets with different retention mechanisms bonded to enamel and to determine the risk of enamel damage after debonding.
  
  
  METHODS
  In this interventional in-vitro study, 36 maxillary premolars were divided into 3 groups. Three types of orthodontic brackets (metal, ceramic with chemical retention, and ceramic with mechanical retention) were bonded to the teeth with a luting resin composite. The brackets were debonded with a sharp-edged debonding pliers in a universal testing machine. Enamel cracks were evaluated with a stereomicroscope. The amount of residual adhesive on the enamel surfaces was evaluated with the adhesive remnant index.
  
  
  RESULTS
  The mean bond strength for the metal brackets was significantly higher than that of the 2 ceramic brackets (P <.001). No significant difference between the mean bond strengths for the 2 ceramic brackets was observed (P = .238). There was no statistically significant difference in the number (P = .871) or length (P = .188) of enamel cracks among the 3 groups. There were significant differences in the adhesive remnant index scores between metal and chemically retained ceramic brackets (P = .007), and between chemically and mechanically retained ceramic brackets (P = .002).
  
  
  CONCLUSIONS
  The risk of enamel damage when debonding ceramic brackets is not greater than the risk when debonding metal brackets.
authors.affiliation: Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Habibi
authors.forename: Tahereh Hosseinzadeh
authors.initials: TH
authors.lastname: Nik
authors.forename: Tabassom
authors.initials: T
authors.lastname: Hooshmand
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid; D002516:Ceramics; D003722:Dental Alloys; D017005:Dental Debonding / Q000009:adverse effects; D003743:Dental Enamel / Q000293:injuries; D003799:Dental Stress Analysis; D006801:Humans; D008422:Materials Testing; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D013193:Stainless Steel; D018709:Statistics, Nonparametric
chemical_list: D003722:Dental Alloys; D013193:Stainless Steel