title: Cytotoxicity of a new toothpaste based on an ion exchange resin mixture.
abstract: OBJECTIVE
  To evaluate the effects for cytotoxicity of two dentifrices: a toothpaste commercially available (Crest Extra-Whitening toothpaste) and a new experimental toothpaste based on a mixture of ion-exchange resins (named NMTD) that supplies calcium, fluoride, phosphate and zinc ions.
  
  
  METHODS
  Cultures of mouse fibroblasts cells L929 were used in a MTT assay for in vitro cytotoxicity of the dentifrices. Cells were cultured in Eagle's minimal essential medium supplemented with 10% fetal bovine serum. Cultures were incubated at 37 degrees C in a humidified atmosphere of 5% CO2 and collected by tripsinization (0.05% trypsin/0.5mM EDTA). A 96-well microplate method was employed for the MTT colorimetric assay. Positive control consisted of 10 microl of phenol in 5 ml of 6% media, a dose that produces zero percent cell survival. Negative control was prepared by adding 0.5 ml of HBSS to 4.5 ml of 6% media. The plates were incubated for 24 and 48 hours at 37 degrees C in a 5% CO2 atmosphere.
  
  
  RESULTS
  Means and standard deviations of absorbance values for each group and percentage inhibitory dosage (%ID) for each test material were calculated. None of the dentifrices resulted in a percentage of inhibition higher than 50% and did not observe marked increases in cytotoxicity with time of incubation. The positive control gave almost zero percent cell survival, whereas the negative control gave a hundred percent cell survival. Analysis of the results indicated that test dentifrice dose had no significant effect towards the cell viability (P<0.05).
authors.affiliation: Analytical Chemistry, Autonomous University of Barcelona, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Torrado
authors.forename: Manuel
authors.initials: M
authors.lastname: Valiente
authors.forename: Wu
authors.initials: W
authors.lastname: Zhang
authors.forename: Yiming
authors.initials: Y
authors.lastname: Li
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Muñoz
mesh_terms: D000818:Animals; D002118:Calcium / Q000008:administration & dosage; D002470:Cell Survival / Q000187:drug effects; D003124:Colorimetry; D004396:Coloring Agents; D005347:Fibroblasts / Q000187:drug effects*; D005459:Fluorides / Q000008:administration & dosage; D007475:Ion Exchange Resins / Q000633:toxicity*; D007739:L Cells; D051379:Mice; D010710:Phosphates / Q000008:administration & dosage; D013778:Tetrazolium Salts; D013844:Thiazoles; D014089:Tooth Remineralization / Q000379:methods*; D014100:Toothpastes / Q000633:toxicity*; D015032:Zinc / Q000008:administration & dosage
chemical_list: D004396:Coloring Agents; D007475:Ion Exchange Resins; D010710:Phosphates; D013778:Tetrazolium Salts; D013844:Thiazoles; D014100:Toothpastes; C022616:thiazolyl blue; D015032:Zinc; D005459:Fluorides; D002118:Calcium