title: Immediate and late analysis of dental pulp stem cells viability after indirect exposition to alternative in-office bleaching strategies.
abstract: OBJECTIVE
  To evaluate human dental pulp stem cell viability and capacity to recover from experimental dental bleaching techniques.
  
  
  METHODS
  Enamel/dentin disks adapted to trans-wells were positioned on previously cultivated dental pulp stem cells. Bleaching gels containing 35, 17.5, 10, and 8 % hydrogen peroxide (H2O2) were applied one or three times (each application lasting 15 min) on enamel. Cell viability (MTT assay) and morphology (SEM) were evaluated immediately (T1) or 72 h (T2) post-bleaching.
  
  
  RESULTS
  The 35 % H2O2 gel promoted intense reduction in viability (93-97 %) and morphological alterations of the cells at T1, irrespective of frequency of application, with absence or limited capacity for recovery being observed at T2. The other bleaching gels presented significant lower toxicity when compared with the 35 % H2O2 gel, in a time/concentration fashion. In T1, no significant difference was observed between the negative control (without bleaching) and the 8 and 10 % H2O2 gels applied on enamel for 15 min, in which the cells presented elevated viability and morphology similar to the negative control at T2.
  
  
  CONCLUSIONS
  Bleaching gels with 8 and 10 % H2O2 in their composition cause limited immediate toxic effect on pulp stem cells, which recover their viability 3 days after treatment.
  
  
  CONCLUSIONS
  This study presents proposals for in-office dental bleaching to be performed with limited aggressive effect on dental pulp stem cells. Therefore, we are able to offer interesting clinical alternatives for bleaching vital teeth, under professional supervision, maintaining the integrity and reparative capacity of pulp-dentin complex.
authors.affiliation: Department of Physiology and Pathology, Univ. Estadual Paulista - UNESP, Araraquara School of Dentistry, Humaitá Street, 1680, Araraquara, SP, Brazil, 14801-903.
authors.forename: Diana Gabriela
authors.initials: DG
authors.lastname: Soares
authors.forename: Fernanda Gonçalves
authors.initials: FG
authors.lastname: Basso
authors.forename: Josimeri
authors.initials: J
authors.lastname: Hebling
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: de Souza Costa
mesh_terms: D000818:Animals; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology*; D005782:Gels; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity*; D066298:In Vitro Techniques; D013234:Stem Cells / Q000187:drug effects*; D013499:Surface Properties; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000633:toxicity*
chemical_list: D005782:Gels; D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide