title: Effect of acidity of in-office bleaching gels on tooth sensitivity and whitening: a two-center double-blind randomized clinical trial.
abstract: OBJECTIVE
  The study aimed to compare the tooth sensitivity (TS) and bleaching efficacy of two hydrogen peroxide gels with different pHs (acid pH [Pola Office, SDI] and the neutral pH [Pola Office+, SDI]) used for in-office bleaching.
  
  
  METHODS
  Fifty-four patients from Brazil and Chile, with right superior incisor darker than A2, were selected for this double-blind, split-mouth randomized trial. Teeth were bleached in two sessions, with 1-week interval. Each session had three applications of 8 min each, according to the manufacturer's instructions. The color changes were evaluated by subjective (Vita Classical and Vita Bleachedguide) and objective (Easy shade spectrophotometer) methods. Participants recorded TS with 0-10 visual analog scale. Color change in shade guide units (SGU) and ΔE was analyzed by Student's t test (α = 0.05). The absolute risk and intensity of TS were evaluated by McNemar's test and Wilcoxon-paired test, respectively (α = 0.05).
  
  
  RESULTS
  All groups achieved the same level of whitening after 30 days of clinical evaluation. The use of a neutral in-office bleaching gel significantly decreases the absolute risk of TS (28%, 95% CI 18-41) and intensity of TS when compared to the acid bleaching gel (absolute risk of 50%, 95% CI 37-63).
  
  
  CONCLUSIONS
  The use of a neutral in-office bleaching agent gel produced the same whitening degree than an acid bleaching gel but with reduced risk and intensity of tooth sensitivity.
  
  
  CONCLUSIONS
  Clinicians should opt to use in-office bleaching with a neutral gel than an acid product because the former causes a significant lower risk and intensity of tooth sensitivity.
authors.affiliation: School of Dentistry, Department of Restorative Dentistry, State University of Ponta Grossa, Ponta Grossa, Parana, Brazil. aloguercio@hotmail.com.|Department of Restorative Dentistry, School of Dentistry, Faculdade de Odontologia, Universidade Estadual de Ponta Grossa, Rua Carlos Cavalcanti, 4748, São Paulo, CEP 84030-900, Brazil. aloguercio@hotmail.com.
authors.forename: A D
authors.initials: AD
authors.lastname: Loguercio
authors.affiliation: School of Dentistry, Department of Restorative Dentistry, Center of Higher Education of Campos Gerais, Ponta Grossa, Brazil.
authors.forename: F
authors.initials: F
authors.lastname: Servat
authors.affiliation: School of Dentistry, Department of Restorative Dentistry, Center of Higher Education of Campos Gerais, Ponta Grossa, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Stanislawczuk
authors.affiliation: School of Dentistry, Department of Restorative Dentistry, Universidad de las Americas, Quito, Ecuador.
authors.forename: A
authors.initials: A
authors.lastname: Mena-Serrano
authors.affiliation: School of Dentistry, Department of Restorative Dentistry, State University of Ponta Grossa, Ponta Grossa, Parana, Brazil.
authors.forename: M
authors.initials: M
authors.lastname: Rezende
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, School of Dentistry of Santiago, Universidad de Chile, Santiago, Chile.
authors.forename: M V
authors.initials: MV
authors.lastname: Prieto
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, School of Dentistry of Santiago, Universidad de Chile, Santiago, Chile.
authors.forename: V
authors.initials: V
authors.lastname: Cereño
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, School of Dentistry of Santiago, Universidad de Chile, Santiago, Chile.
authors.forename: M F
authors.initials: MF
authors.lastname: Rojas
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, School of Dentistry of Santiago, Universidad de Chile, Santiago, Chile.
authors.forename: K
authors.initials: K
authors.lastname: Ortega
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, School of Dentistry of Santiago, Universidad de Chile, Santiago, Chile.|Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile.
authors.forename: E
authors.initials: E
authors.lastname: Fernandez
authors.affiliation: School of Dentistry, Department of Restorative Dentistry, State University of Ponta Grossa, Ponta Grossa, Parana, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Reis
mesh_terms: D001938:Brazil; D002677:Chile; D003807:Dentin Sensitivity / Q000139:chemically induced*; D004311:Double-Blind Method; D005260:Female; D005782:Gels; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008297:Male; D058205:Tooth Bleaching Agents / Q000737:chemistry*; D014075:Tooth Discoloration / Q000188:drug therapy*; D016896:Treatment Outcome
chemical_list: D005782:Gels; D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide
keywords: Acidic gel; In-office bleaching; Neutral gel; Tooth sensitivity; Whitening effectiveness