title: Responses of dental pulp cells to a less invasive bleaching technique applied to adhesive-restored teeth.
abstract: OBJECTIVE
  To assess the cytotoxicity of 35% hydrogen peroxide (HP) bleaching gel applied for 15 min to sound or restored teeth with two-step self-etching adhesive systems and composite resin.
  
  
  METHODS
  Sound and restored enamel/dentin disks were stored in water for 24 h or 6 months + thermocycling. The disks were adapted to artificial pulp chambers and placed in compartments containing culture medium. Immediately after bleaching, the culture medium in contact with dentin was applied for 1 h to previously cultured odontoblast-like MDPC-23 cells. Thereafter, cell viability (MTT assay) and morphology (SEM) were assessed. Data were analyzed by two-way ANOVA and Tukey's test (a = 5%).
  
  
  RESULTS
  In comparison to the negative control group (no treatment), no significant cell viability reduction occurred in those groups in which sound teeth were bleached. However, a significant decrease in cell viability was observed in the adhesive-restored bleached groups compared to negative control. No significant difference among bleached groups was observed with respect to the presence of restoration and storage time.
  
  
  CONCLUSIONS
  The application of 35% HP bleaching gel to sound teeth for 15 min does not cause toxic effects in pulp cells. When this bleaching protocol was performed in adhesive-restored teeth, a significant toxic effect occurred.
authors.forename: Diana Gabriela
authors.initials: DG
authors.lastname: Soares
authors.forename: Nancy Tomoko
authors.initials: NT
authors.lastname: Sacono
authors.forename: Ana Paula Dias
authors.initials: AP
authors.lastname: Ribeiro
authors.forename: Fernanda Gonçalves
authors.initials: FG
authors.lastname: Basso
authors.forename: Débora Sales
authors.initials: DS
authors.lastname: Scheffel
authors.forename: Josimeri
authors.initials: J
authors.lastname: Hebling
authors.forename: Carlos Alberto de Souza
authors.initials: CA
authors.lastname: Costa
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D002417:Cattle; D018929:Cell Culture Techniques; D002460:Cell Line; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003188:Composite Resins / Q000737:chemistry; D003470:Culture Media; D003743:Dental Enamel / Q000187:drug effects; D003764:Dental Materials / Q000737:chemistry; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects*; D003793:Dental Restoration, Permanent / Q000379:methods*; D003804:Dentin / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000633:toxicity*; D055115:Light-Curing of Dental Adhesives; D051379:Mice; D009804:Odontoblasts / Q000187:drug effects; D013696:Temperature; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000633:toxicity*
chemical_list: D003188:Composite Resins; D003470:Culture Media; D003764:Dental Materials; D058205:Tooth Bleaching Agents; C533204:filtek Z350; D006861:Hydrogen Peroxide