title: Toxicity of chlorhexidine on odontoblast-like cells.
abstract: Chlorhexidine gluconate (CHX) is recommended for a number of clinical procedures and it has been pointed out as a potential cavity cleanser to be applied before adhesive restoration of dental cavities.
  
  
  OBJECTIVE
  As CHX may diffuse through the dentinal tubules to reach a monolayer of odontoblasts that underlies the dentin substrate, this study evaluated the cytotoxic effects of different concentrations of CHX on cultured odontoblast-like cells (MDPC-23).
  
  
  METHODS
  Cells were cultured and exposed to CHX solutions at concentrations of 0.06%, 0.12%, 0.2%, 1% and 2%. Pure culture medium (alpha-MEM) and 3% hydrogen peroxide were used as negative and positive control, respectively. After exposing the cultured cells to the controls and CHX solutions for 60 s, 2 h or 60 s with a 24-h recovery period, cell metabolism (MTT assay) and total protein concentration were evaluated. Cell morphology was assessed under scanning electron microscopy. CHX had a dose-dependent toxic effect on the MDPC-23 cells.
  
  
  RESULTS
  Statistically significant difference was observed when the cells were exposed to CHX in all periods (p<0.05). Significant difference was also determined for all CHX concentrations (p<0.05). The 60-s exposure time was the least cytotoxic (p<0.05), while exposure to CHX for 60 s with a 24-h recovery period was the most toxic to the cells (p<0.05).
  
  
  CONCLUSIONS
  Regardless of the exposure time, all CHX concentrations had a high direct cytotoxic effect to cultured MDPC-23 cells.
authors.affiliation: Department of Orthodontics and Pediatric Dentistry, São Paulo State University, Araraquara Dental School, Araraquara, SP, Brazil.
authors.forename: Fernanda Campos Rosetti
authors.initials: FC
authors.lastname: Lessa
authors.forename: Andreza Maria Fabio
authors.initials: AM
authors.lastname: Aranha
authors.forename: Indri
authors.initials: I
authors.lastname: Nogueira
authors.forename: Elisa Maria Aparecida
authors.initials: EM
authors.lastname: Giro
authors.forename: Josimeri
authors.initials: J
authors.lastname: Hebling
authors.forename: Carlos Alberto de Souza
authors.initials: CA
authors.lastname: Costa
mesh_terms: D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000633:toxicity*; D002448:Cell Adhesion / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002710:Chlorhexidine / Q000008:administration & dosage / Q000633:toxicity*; D004396:Coloring Agents; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008928:Mitochondria / Q000187:drug effects; D009804:Odontoblasts / Q000187:drug effects* / Q000378:metabolism; D016877:Oxidants / Q000633:toxicity; D011506:Proteins / Q000032:analysis; D013385:Succinate Dehydrogenase / Q000187:drug effects; D013778:Tetrazolium Salts; D013844:Thiazoles; D013997:Time Factors
chemical_list: D000891:Anti-Infective Agents, Local; D004396:Coloring Agents; D016877:Oxidants; D011506:Proteins; D013778:Tetrazolium Salts; D013844:Thiazoles; D006861:Hydrogen Peroxide; D013385:Succinate Dehydrogenase; C022616:thiazolyl blue; D002710:Chlorhexidine