The cytotoxic effect of TiF4 and NaF on fibroblasts is influenced by the experimental model, fluoride concentration and exposure time

• Published in: PloS one Vol. 12; no. 6; p. e0179471
• Main Authors: Salomão, Priscila Maria Aranda, Oliveira, Flávia Amadeu de, Rodrigues, Paula Danielle, Al-Ahj, Luana Polioni, Gasque, Kellen Cristina da Silva, Jeggle, Pia, Buzalaf, Marilia Afonso Rabelo, Oliveira, Rodrigo Cardoso de, Edwardson, John Michael, Magalhães, Ana Carolina
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14-06-2017; Public Library of Science (PLoS)
• Subjects: Animals; Antibiotics; Apoptosis; Assaying; Atomic force microscopy; Biocompatibility; Biology and Life Sciences; Cariostatic Agents - pharmacology; Cell Physiological Phenomena - drug effects; Cell Survival - drug effects; Cytotoxicity; Dental caries; Dentistry; Dose-Response Relationship, Drug; Enamel; Exposure; Fibroblasts; Fibroblasts - cytology; Fibroblasts - drug effects; Fluoridation; Fluoride; Fluorides; Fluorides - pharmacology; Hydrogen-Ion Concentration; In vivo methods and tests; Laboratories; Lesions; Mathematical models; Medicine and Health Sciences; Mice; Microscopy; Microscopy, Atomic Force; Models, Theoretical; Nanoparticles; NIH 3T3 Cells; Physical Sciences; Research and analysis methods; Sodium; Sodium fluoride; Sodium Fluoride - pharmacology; Stiffness; Teeth; Time Factors; Titanium; Titanium - pharmacology; Toxicity; Toxicology; Varnishes
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0179471

Titanium tetrafluoride (TiF4) has shown promising effect in preventing tooth lesions. Therefore, we compared the cytotoxicity of TiF4 with sodium fluoride (NaF) (already applied in Dentistry) considering different fluoride concentrations, pH values and experimental models.
Step 1) NIH/3T3 fibroblasts were exposed to mediums containing NaF or TiF4 (from 0.15 to 2.45% F), both at native and adjusted pH, for 6 h. Step 2) NIH/3T3 were exposed to NaF or TiF4 varnishes with 0.95, 1.95 or 2.45% F (native pH), for 6, 12 or 24 h. We applied MTT (1st and 2nd steps) and Hoescht/PI stain (2nd step) assays. Step 3) NIH/3T3 were exposed to NaF or TiF4 varnish (2.45% F), at native pH, for 6 or 12 h. The cell stiffness was measured by atomic force microscopy (AFM).
Step 1) All cells exposed to NaF or TiF4 mediums died, regardless of the F concentration and pH. Step 2) Both varnishes, at 1.90 and 2.45% F, reduced cell viability by similar extents (33-86% at 6 h, 35-93% at 12 h, and 87-98% at 24 h) compared with control, regardless of the type of fluoride. Varnishes with 0.95% F did not differ from control. Step 3) TiF4 and NaF reduced cell stiffness to a similar extent, but only TiF4 differed from control at 6 h.
Based on the results of the 3 experimental steps, we conclude that TiF4 and NaF have similar cytotoxicity. The cytotoxicity was dependent on F concentration and exposure time. This result gives support for testing the effect of TiF4 varnish in vivo.