title: Effect of halogen light irradiation on hydrogen peroxide bleaching: an in vitro study.
abstract: BACKGROUND
  The aim of this study was to evaluate the effect of halogen light irradiation on hydrogen peroxide (HP) bleaching by assessing HP concentrations, tooth whitening efficacy, and temperature variations in bleaching agents and pulp chambers.
  
  
  METHODS
  Sixteen premolars were randomly divided into two groups: Group BL (bleaching agent with halogen light irradiation for 3 × 10 minutes) and Group B (bleaching agent alone). HP concentrations were tested before and after treatment. CIE L*a*b* values of specimens were obtained using a spectrophotometer. Temperatures of bleaching gels and pulpal chambers were recorded by a digital multimeter with K-type thermocouple. Data were analysed using ANOVA and paired t-test.
  
  
  RESULTS
  After treatment, HP concentration in group BL was slightly higher than that in group B. Paired t-tests revealed significant differences of ΔE between groups BL and B in all time intervals except at day 35. The temperature rise of bleaching gels and pulpal chambers in group BL was significantly higher than that in group B.
  
  
  CONCLUSIONS
  In-office bleaching was effective for tooth whitening. The involvement of halogen light was beneficial for the immediate whitening effect but had little impact on the long-term whitening effect.
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: S
authors.initials: S
authors.lastname: Liang
authors.forename: Y
authors.initials: Y
authors.lastname: Sa
authors.forename: L
authors.initials: L
authors.lastname: Sun
authors.forename: X
authors.initials: X
authors.lastname: Ma
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: W
authors.initials: W
authors.lastname: Xing
authors.forename: T
authors.initials: T
authors.lastname: Jiang
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000704:Analysis of Variance; D001641:Bicuspid / Q000737:chemistry*; D003116:Color; D055117:Curing Lights, Dental; D003786:Dental Pulp Cavity / Q000528:radiation effects*; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis; D066298:In Vitro Techniques; D013053:Spectrophotometry; D013696:Temperature; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000032:analysis
chemical_list: D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide