title: Effect of tooth bleaching on orthodontic stainless steel bracket bond strength.
abstract: OBJECTIVE
  The objective was to assess the shear bond strength (SBS) of composite resins on stainless steel brackets immediately bonded to previously bleached teeth with 35% hydrogen peroxide and to compare the neutralization effect of various antioxidant agents on the bond strength after bleaching.
  
  
  METHODS
  One hundred sound human maxillary premolars were used for the study. Teeth were divided into 5 groups (n = 20); Group 1 (control), Group 2 (bleach treatment), Group 3 (sodium ascorbate treatment), Group 4 (tocopherol acetate treatment), and Group 5 (retinol acetate treatment). Teeth in Group 3, 4, and 5 were treated as in Group 2, but after that and before bleaching received treatment with sodium ascorbate, tocopherol acetate, and retinol acetate, respectively. Subsequently, teeth were bonded with stainless steel brackets (Ormco) using 3M Transbond XT. After 24 h, each specimen was loaded into a universal testing machine to determine the SBS at debonding. The data were exposed to the analysis of variance, Bonferroni, and Weibull Analysis.
  
  
  RESULTS
  There significant SBS difference (P = 0.000, F = 32.125) between various groups. Group 1 had the highest SBS (12.182 ± 1.41 MPa) and Group 2 the least SBS (6.182 ± 1.49 MPa). Significant SBS differences observed between Group 1 and 2; Group 2 and 3; Group 2 and 4; and Group 2 and 5 (P = 0.000). There was no significant SBS difference between Group 1 and 3; Group 1 and 4; and Group 3 and 4 (P = 1.000). Bonferroni results also indicated that there was a significant difference between Group 1 and 5 (P = 0.002); Group 3 and 5 (P = 0.144); and between Group 4 and 5 (P = 0.008). Weibull analysis indicated that bond strength for a 90% probability of failure, which was highest for Group 1 (13.99 MPa) and lowest for Group 2 (8.49 MPa).
  
  
  CONCLUSIONS
  The in-vitro study showed that bleaching with 35% hydrogen peroxide reduced the SBS significantly and this could be effectively reversed by the application of 10% sodium ascorbate, 10% tocopherol acetate, or 10% retinol acetate. Thus, treatment of bleached teeth with antioxidants can be a good clinical option for bonding immediately after bleaching.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Inderprastha Dental College and Hospital, Sahibabad, Ghaziabad, India.
authors.forename: Deepti
authors.initials: D
authors.lastname: Yadav
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Inderprastha Dental College and Hospital, Sahibabad, Ghaziabad, India.
authors.forename: Vineet
authors.initials: V
authors.lastname: Golchha
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Inderprastha Dental College and Hospital, Sahibabad, Ghaziabad, India.
authors.forename: Rahul
authors.initials: R
authors.lastname: Paul
authors.affiliation: Amity Institute of Physiotherapy, Amity University, Noida, Uttar Pradesh, India.
authors.forename: Pooja
authors.initials: P
authors.lastname: Sharma
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Inderprastha Dental College and Hospital, Sahibabad, Ghaziabad, India.
authors.forename: Jitesh
authors.initials: J
authors.lastname: Wadhwa
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Inderprastha Dental College and Hospital, Sahibabad, Ghaziabad, India.
authors.forename: Sidhant
authors.initials: S
authors.lastname: Taneja
keywords: Antioxidants; bleaching; bonding; shear bond strength