Effect of three fluoride compounds on the growth of oral normal and tumor cells.

Aim: Comparative study of the growth inhibition by different types of fluoride compounds used in dentistry has been limited. We investigated the effects of sodium fluoride (NaF), diammine silver fluoride [Ag(NH3)2F] and 5-fluorouracil (5-FU) on the growth of eleven human normal and tumor cells in total.

Materials And Methods: Viable cell number was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.

Enhancement of cytotoxic activity of sodium fluoride against human periodontal ligament fibroblasts by water pressure.

Whether or not water pressure enhances the cytotoxic activity of sodium fluoride (NaF) against human periodontal ligament fibroblast (HPLF) was investigated. Loading with water pressure (up to 5 g) alone did not affect the cell proliferation, but significantly enhanced the cytotoxic activity of millimolar concentrations of NaF. Cytotoxic activity of NaF was reduced by supplementation with Ca2+, whereas it was enhanced by removal of Ca2+ from the culture medium.

Changes in fluoride sensitivity during in vitro senescence of normal human oral cells.

We have previously reported that sodium fluoride (NaF) showed slightly higher cytotoxicity against human oral tumor cell lines than normal human oral cells. Possible changes in the NaF sensitivity of three normal human oral cell types (gingival fibroblast HGF, pulp cell HPC, periodontal ligament fibroblast HPLF) during in vitro ageing were investigated in the present study. When these cells were subcultured at 1:4 split ratio every week, their saturation density declined with increasing population doubling level (PDL), and they ceased to divide when they reached 20 PDL.

Effect of antitumor agents on cytotoxicity induction by sodium fluoride.

We have recently found that sodium fluoride (NaF) induced apoptotic cell death in tumor cell lines. We investigated here whether 6 popular antitumor compounds modify the cytotoxic activity of NaF against human squamous cell carcinoma (HSC-2) and human promyelocytic leukemia (HL-60) cell lines. Cytotoxic concentrations of cisplatin, etoposide, doxorubicin or peplomycin (tentatively termed as Group I compounds), but not methotrexate and 5-FU (tentatively termed as Group II compounds), enhanced the cytotoxic activity of NaF.

Effect of endodontic agents on cytotoxicity induction by sodium fluoride.

We investigated six endodontic agents for their ability to induce apoptosis and modify the cytotoxic activity of NaF against human squamous cell carcinoma (HSC-2) and human promyelocytic leukemia (HL-60) cell lines. Four Group I agents (Form Cresol, Cam Phenic, Eucaly Soft, GC Fuji Varnish), but not two Group II agents (Caviton, Canals-N), induced internucleosomal DNA fragmentation and activated caspases 3, 8 and 9 in HL-60 cells. Only Cam Phenic among these agents additively enhanced the cytotoxic activity of NaF in HSC-2 and HL-60 cells.

Effect of antioxidants, oxidants, metals and saliva on cytotoxicity induction by sodium fluoride.

We have recently found that millimolar concentrations of sodium fluoride (NaF) induced apoptotic cell death, characterized by caspase activation and DNA fragmentation, in tumor cell lines. This finding paved the way to investigating the interaction between NaF and the oral environment. As an initial step, we investigated redox compounds, metals and saliva, which may modify the cytotoxic activity of NaF against a human oral squamous cell carcinoma cell line (HSC-2).