title: Effect of ProRoot MTA mixed with chlorhexidine on apoptosis and cell cycle of fibroblasts and macrophages in vitro.
abstract: OBJECTIVE
  To compare the percentage of apoptotic cells and the cell cycle profile of fibroblasts and macrophages exposed to either ProRoot mineral trioxide aggregate (MTA) mixed with chlorhexidine (CHX), or exposed to ProRoot MTA mixed with sterile water.
  
  
  METHODS
  Mouse gingival fibroblasts or mouse macrophages were seeded in six-well plates and allowed to attach overnight. Freshly mixed or set (allowed to dry for 24 h) specimens of tooth-coloured (white) ProRoot MTA were prepared with 0.12% CHX gluconate (MTA/CHX) or with sterile water (MTA/H2O). The cells were exposed for 24 h to the MTA specimens, which were placed over permeable membrane inserts to avoid direct contact with the cells. Untreated cells served as controls. Propidium iodide staining followed by flow cytometry was used to evaluate the effects of ProRoot MTA on cell apoptosis and cell cycle. Statistical analyses were performed by one-way anova followed by post-hoc tests with the use of the SigmaStat 2.0 software, and significance was determined at P < or = 0.05.
  
  
  RESULTS
  MTA specimens containing CHX induced apoptosis of macrophages and fibroblasts (P < 0.05). In contrast, no change in the proportion of apoptotic cells was observed when sterile water was used to prepare the specimens (P > 0.05). Cell cycle analysis showed that exposure to MTA/CHX decreased the percentage of fibroblasts and macrophages in S phase (DNA synthesis) as compared with exposure to MTA/H2O (P < 0.05).
  
  
  CONCLUSIONS
  This in vitro study demonstrated that the substitution of CHX for sterile water in MTA increases its cytotoxicity. This suggests that the potentially beneficial antimicrobial effect of CHX may be accompanied by an increase in the cytotoxicity of the resulting MTA-based material.
authors.affiliation: Department of Cariology, Restorative Sciences and Endodontics, University of Michigan School of Dentistry, Ann Arbor, MI, 48103-1078 USA.
authors.forename: E P
authors.initials: EP
authors.lastname: Hernandez
authors.forename: T M
authors.initials: TM
authors.lastname: Botero
authors.forename: M G
authors.initials: MG
authors.lastname: Mantellini
authors.forename: N J
authors.initials: NJ
authors.lastname: McDonald
authors.forename: J E
authors.initials: JE
authors.lastname: Nör
mesh_terms: D017607:Aluminum Compounds / Q000633:toxicity; D000704:Analysis of Variance; D000818:Animals; D000891:Anti-Infective Agents, Local / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D017610:Calcium Compounds / Q000633:toxicity; D002453:Cell Cycle / Q000187:drug effects*; D002478:Cells, Cultured; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000633:toxicity; D004338:Drug Combinations; D005347:Fibroblasts / Q000187:drug effects*; D005434:Flow Cytometry; D005881:Gingiva / Q000166:cytology / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D010087:Oxides / Q000633:toxicity; D012387:Root Canal Filling Materials / Q000633:toxicity*; D016196:S Phase; D017640:Silicates / Q000633:toxicity
chemical_list: D017607:Aluminum Compounds; D000891:Anti-Infective Agents, Local; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate; C010882:chlorhexidine gluconate; D002710:Chlorhexidine