title: The effects of light on bleaching and tooth sensitivity during in-office vital bleaching: a systematic review and meta-analysis.
abstract: OBJECTIVE
  To evaluate the influence of light on bleaching efficacy and tooth sensitivity during in-office vital bleaching.
  
  
  METHODS
  We performed a literature search using Medline, EMBASE and Cochrane Central up to September 2011.
  
  
  METHODS
  All randomised controlled trials (RCTs) or quasi-RCTs comparing the light-activated bleaching system with non-activation bleaching system were included. Reports without clinical data concerning bleaching efficacy or tooth sensitivity were excluded.
  
  
  RESULTS
  Eleven studies were included in the meta-analysis. A light-activated system produced better immediate bleaching effects than a non-light system when lower concentrations of hydrogen peroxide (15-20% HP) were used (mean difference [MD], -1.78; 95% confidence interval [CI]: [-2.30, -1.26]; P<0.00001). When high concentrations of HP (25-35%) were employed, there was no difference in the immediate bleaching effect (MD, -0.39; 95% CI: [-1.15, 0.37]; P=0.32) or short-term bleaching effect (MD, 0.25; 95% CI: [-0.47, 0.96]; P=0.50) between the light-activated system and the non-light system. However, the light-activated system produced a higher percentage of tooth sensitivity (odds ratio [OR], 3.53; 95% CI: [1.37, 9.10]; P=0.009) than the non-light system during in-office bleaching.
  
  
  CONCLUSIONS
  Light increases the risk of tooth sensitivity during in-office bleaching, and light may not improve the bleaching effect when high concentrations of HP (25-35%) are employed. Therefore, dentists should use the light-activated system with great caution or avoid its use altogether. Further rigorous studies are, however, needed to explore the advantages of this light-activated system when lower concentrations of HP (15-20%) are used.
authors.affiliation: State Key Laboratory of Oral Diseases, Sichuan University, Chengdu, China.
authors.forename: Li-Bang
authors.initials: LB
authors.lastname: He
authors.forename: Mei-Ying
authors.initials: MY
authors.lastname: Shao
authors.forename: Ke
authors.initials: K
authors.lastname: Tan
authors.forename: Xin
authors.initials: X
authors.lastname: Xu
authors.forename: Ji-Yao
authors.initials: JY
authors.lastname: Li
mesh_terms: D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000528:radiation effects; D008027:Light; D028022:Low-Level Light Therapy / Q000379:methods; D038761:Photobleaching; D016032:Randomized Controlled Trials as Topic; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000008:administration & dosage / Q000528:radiation effects*; D014098:Toothache / Q000209:etiology*
chemical_list: D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide