title: Comparative clinical study of the effectiveness of different dental bleaching methods - two year follow-up.
abstract: This study evaluated color change, stability, and tooth sensitivity in patients submitted to different bleaching techniques.
  
  
  METHODS
  In this study, 48 patients were divided into five groups. A half-mouth design was conducted to compare two in-office bleaching techniques (with and without light activation): G1: 35% hydrogen peroxide (HP) (Lase Peroxide - DMC Equipments, São Carlos, SP, Brazil) + hybrid light (HL) (LED/Diode Laser, Whitening Lase II DMC Equipments, São Carlos, SP, Brazil); G2: 35% HP; G3: 38% HP (X-traBoost - Ultradent, South Jordan UT, USA) + HL; G4: 38% HP; and G5: 15% carbamide peroxide (CP) (Opalescence PF - Ultradent, South Jordan UT, USA). For G1 and G3, HP was applied on the enamel surface for 3 consecutive applications activated by HL. Each application included 3x3' HL activations with 1' between each interval; for G2 and G4, HP was applied 3x15' with 15' between intervals; and for G5, 15% CP was applied for 120'/10 days at home. A spectrophotometer was used to measure color change before the treatment and after 24 h, 1 week, 1, 6, 12, 18 and 24 months. A VAS questionnaire was used to evaluate tooth sensitivity before the treatment, immediately following treatment, 24 h after and finally 1 week after.
  
  
  RESULTS
  Statistical analysis did not reveal any significant differences between in-office bleaching with or without HL activation related to effectiveness; nevertheless the time required was less with HL. Statistical differences were observed between the results after 24 h, 1 week and 1, 6, 12, 18 and 24 months (intergroup). Immediately, in-office bleaching increased tooth sensitivity. The groups activated with HL required less application time with gel.
  
  
  CONCLUSIONS
  All techniques and bleaching agents used were effective and demonstrated similar behaviors.
authors.affiliation: Department of Restorative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, São Paulo, Brazil. rafamond@fob.usp.br
authors.forename: Rafael Francisco Lia
authors.initials: RF
authors.lastname: Mondelli
authors.forename: Juliana Felipi David E Góes de
authors.initials: JF
authors.lastname: Azevedo
authors.forename: Ana Carolina
authors.initials: AC
authors.lastname: Francisconi
authors.forename: Cristiane Machado de
authors.initials: CM
authors.lastname: Almeida
authors.forename: Sérgio Kiyoshi
authors.initials: SK
authors.lastname: Ishikiriama
mesh_terms: D000293:Adolescent; D000328:Adult; D000077463:Carbamide Peroxide; D003116:Color; D003743:Dental Enamel / Q000187:drug effects; D003807:Dentin Sensitivity; D005500:Follow-Up Studies; D005782:Gels; D006801:Humans; D006861:Hydrogen Peroxide / Q000627:therapeutic use*; D008422:Materials Testing; D010545:Peroxides / Q000627:therapeutic use*; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000627:therapeutic use*; D016896:Treatment Outcome; D014508:Urea / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D005782:Gels; D010545:Peroxides; D058205:Tooth Bleaching Agents; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide