title: Morphological alterations associated with the cytotoxic and cytostatic effects of citric acid on cultured human dental pulp cells.
abstract: Citric acid exerts potential harmful effects on the pulp when used for root surface demineralization, smear layer removal, and dentin etching. Using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay, we found that incubation of cultured human dental pulp cells in medium containing 0.5% (pH 4.74) or 1.0% (pH 3.42) of citric acid for 2 h lead to 25% and 48% of cell death, respectively. Cytotoxicity of citric acid was associated with its acidity. Exposure of cells to pure 1% citric acid (pH 2.26) for 60 s lead to immediate cell death. Cytotoxicity was usually preceded by cell retraction, cell surface blebbing, and finally uptake of trypan blue, implicating the presence of cell membrane damage. A medium containing 0.05% citric acid can retard the growth of pulp cells. These results indicate that adequate protection of the pulp is important, especially when the remaining dentin is thin in deep carious lesions or in the presence of accessory canals on the root surface.
authors.affiliation: Department of Dentistry, Chang-Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: C P
authors.initials: CP
authors.lastname: Chan
authors.forename: J H
authors.initials: JH
authors.lastname: Jeng
authors.forename: C C
authors.initials: CC
authors.lastname: Hsieh
authors.forename: C L
authors.initials: CL
authors.lastname: Lin
authors.forename: D
authors.initials: D
authors.lastname: Lei
authors.forename: M C
authors.initials: MC
authors.lastname: Chang
mesh_terms: D000134:Acid Etching, Dental / Q000009:adverse effects; D002455:Cell Division / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects; D002478:Cells, Cultured; D019343:Citric Acid / Q000633:toxicity*; D003239:Connective Tissue Cells / Q000187:drug effects; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration
chemical_list: D019343:Citric Acid