title: Comparative evaluation of superoxide dismutase, alpha-tocopherol, and 10% sodium ascorbate on reversal of shear bond strength of bleached enamel: An in vitro study.
abstract: OBJECTIVE
  The aim of this study was to investigate the neutralizer effect of antioxidant agents on the bond strength of bleached enamel.
  
  
  METHODS
  Sixty enamel slabs were prepared from 60 freshly extracted maxillary central incisors and were divided into six groups. The negative control group received no bleaching treatment and the other groups were bleached with 35% carbamide peroxide (Opalescence Quick; Ultradent, South Jordan, USA). In Group II, composite was built immediately after bleaching and cured without any antioxidants. In Group III, bleached specimens received composite build ups delayed by 1 week. In Groups IV, V, and VI bleached specimens received applications of superoxide dismutase (SOD), sodium ascorbate (SA), and tocopherol solutions, respectively, for 10 min. Following composite bonding, the micro shear bond strength (μSBS) was measured at a speed of 1 mm/min in universal testing machine.
  
  
  METHODS
  The μSBS values of all the groups were analyzed using the analysis of variance followed by Tukey honestly significant difference post-hoc test.
  
  
  RESULTS
  Bonding of composites to unbleached group (Group I) exhibited the highest mean SBS values and among the antioxidant-treated groups, the highest SBS values were seen with SOD (Group IV) treated samples (23.0040 ± 4.30565 MPa).
  
  
  CONCLUSIONS
  Application of SA, alpha-tocopherol, and SOD can effectively reverse the bond strength with bleached enamel. SOD gave a comparatively more promising reversal of bond strength than SA and alpha-tocopherol, and deserves further studies.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Tamil Nadu Government Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Mahendran
authors.initials: M
authors.lastname: Kavitha
authors.affiliation: Department of Conservative Dentistry and Endodontics, Tamil Nadu Government Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Sharmila
authors.initials: S
authors.lastname: Selvaraj
authors.affiliation: Department of Conservative Dentistry and Endodontics, Tamil Nadu Government Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Ambica
authors.initials: A
authors.lastname: Khetarpal
authors.affiliation: Department of Conservative Dentistry and Endodontics, Tamil Nadu Government Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Aruna
authors.initials: A
authors.lastname: Raj
authors.affiliation: Department of Conservative Dentistry and Endodontics, Tamil Nadu Government Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Shakunthala
authors.initials: S
authors.lastname: Pasupathy
authors.affiliation: Department of Conservative Dentistry and Endodontics, Tamil Nadu Government Dental College and Hospital, Chennai, Tamil Nadu, India.
authors.forename: Shobana
authors.initials: S
authors.lastname: Shekar
keywords: Alpha-tocopherol; shear bond strength; sodium ascorbate; superoxide dismutase