title: Evaluation of bleaching efficacy of 37.5% hydrogen peroxide on human teeth using different modes of activations: An in vitro study.
abstract: BACKGROUND
  The aim of this in vitro study is to evaluate the role of light and laser sources in the bleaching ability of 37.5% H2 O2 on extracted human teeth.
  
  
  METHODS
  About 30 caries-free single-rooted maxillary central incisors were used for the study. Specimens were prepared by sectioning the crown portion of teeth mesiodistally, and labial surface was used for the study. Specimens were then immersed in coffee solution for staining. Color of each tooth was analyzed using Shadestar, a digital shademeter. Specimens were then divided into three groups of 10 each and were subjected to bleaching with 37.5% H2 O2, 37.5% H2 O2 + light activation, and 37.5% H2 O2 + laser activation, respectively. Postbleaching, the color was analyzed for all the specimens immediately and then after 1, 2, and 3 weeks intervals, respectively.
  
  
  RESULTS
  All the statistical analyses were done using SPSS version 17. Intra- and inter-group comparisons were done with Friedman test and Kruskal-Wallis ANOVA, respectively. Statistical analysis concluded with a significant improvement in their shade values from baseline in all the three groups. Halogen light activation and laser-activated groups showed comparatively enhanced bleaching results over no-activation group, though the difference was not statistically significant.
  
  
  CONCLUSIONS
  The results of the present study show that bleaching assisted with halogen light and laser showed increased lightness than nonlight activated group. Durability of bleaching results obtained postbleaching was maintained throughout the experimental trail period of 3 weeks for both halogen light and laser activation group, whereas no-light activation group presented with shade rebound after 2 weeks postbleaching.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India.
authors.forename: Neha
authors.initials: N
authors.lastname: Bhutani
authors.affiliation: Department of Conservative Dentistry and Endodontics, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India.
authors.forename: Bhuvan Shome
authors.initials: BS
authors.lastname: Venigalla
authors.affiliation: Department of Conservative Dentistry and Endodontics, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India.
authors.forename: Jaya Prakash
authors.initials: JP
authors.lastname: Patil
authors.affiliation: Department of Conservative Dentistry and Endodontics, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India.
authors.forename: Thakur Veerandar
authors.initials: TV
authors.lastname: Singh
authors.affiliation: Department of Conservative Dentistry and Endodontics, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India.
authors.forename: Sistla Venkata
authors.initials: SV
authors.lastname: Jyotsna
authors.affiliation: Department of Conservative Dentistry and Endodontics, Sri Sai College of Dental Surgery, Vikarabad, Telangana, India.
authors.forename: Abhilasha
authors.initials: A
authors.lastname: Jain
keywords: Bleaching; halogen light; hydrogen peroxide; laser; shade star