Fluoride Action Network


Objectives: Toothpastes and mouthwashes contain ingredients that may be toxic for oral mucosal tissues. This study aimed to assess the cytotoxicity of the ingredients of commonly used toothpastes and mouthwashes.

Materials and methods: This experimental study was performed on 16 toothpastes and four mouthwashes widely available in the Iranian market. First, the concentration of six main ingredients of these products, namely sodium fluoride (NaF), sodium lauryl sulfate, cocamidopropyl betaine, zinc lactate, paraben, and sodium benzoate, was determined. The methyl thiazolyl tetrazolium (MTT) assay was used to assess the cytotoxicity of these materials for human gingival fibroblasts (HGFs). The MTT assay was performed at 1, 15, and 30 minutes following exposure to five concentrations of each material in triplicate (according to the concentrations obtained in the isolation step). Data were analyzed using three-way analysis of variance (ANOVA).

Results: The difference in the cytotoxicity of the materials was statistically significant (P<0.001). Cytotoxicity was time- and concentration-dependent; by an increase in the concentration of the materials, their cytotoxicity increased over time. The cytotoxicity of sodium lauryl sulfate and cocamidopropyl betaine was >90%. The cytotoxicity of NaF varied from 25% to 70%, and the cytotoxicity of all concentrations of zinc lactate and sodium benzoate was <50% for HGFs.

Conclusion: To decrease the cytotoxic effects of toothpastes, sodium lauryl sulfate and cocamidopropyl betaine should be replaced with safer detergents, and the concentration of fluoride should be decreased to 400 parts per million (ppm). Alternatively, fluoride may be replaced with other antibacterial and cariostatic agents.

Keywords: Cytotoxicity Tests, Immunologic; Parabens; Sodium Benzoate; Sodium Dodecyl Sulfate; Sodium Fluoride; Zinc; cocamidopropyl betaine.


  1. Binney A, Addy M, Newcombe RG. The plaque removal effects of single rinsings and brushings. J Periodontol. 1993 Mar;64(3):181-5.
  2. Ghapanchi J, Kamali F, Moattari A, Poorshahidi S, Shahin E, Rezazadeh F, et al. In vitro comparison of cytotoxic and antibacterial effects of 16 commercial toothpastes. J Int Oral Health. 2015 Mar;7(3):39-43.
  3. Torrado A, Valiente M, Zhang W, Li Y, Muñoz CA. Cytotoxicity of a new toothpaste based on an ion exchange resin mixture. Am J Dent. 2005 Aug;18(4):267-9.
  4. Cvikl B, Lussi A, Gruber R. The in vitro impact of toothpaste extracts on cell viability. Eur J Oral Sci. 2015 Jun;123(3):179-85.
  5. Barbier O, Arreola-Mendoza L, Del Razo LM. Molecular mechanisms of fluoride toxicity. Chem Biol Interact. 2010 Nov 5;188(2):319-33.
  6. Ritter AV, Eidson RS, Donovan TE. Dental caries: etiology, clinical characteristics, risk assessment, and management. In: Heymann HO, Swift EJ, Ritter AV (editors). Sturdevant’s Art and Science of Operative Dentistry. Elsevier/Mosby, St. Louis, MO, 2013:41-88.
  7. Healy CM, Cruchley AT, Thornhill MH, Williams DM. The effect of sodium lauryl sulphate, triclosan and zinc on the permeability of normal oral mucosa. Oral Dis. 2000 Mar;6(2):118-23.
  8. Herlofson BB, Brodin P, Aars H. Increased human gingival blood flow induced by sodium lauryl sulfate. J Clin Periodontol. 1996 Nov;23(11):1004-7.
  9. Haraszthy VI, Zambon JJ, Sreenivasan PK. Evaluation of the antimicrobial activity of dentifrices on human oral bacteria. J Clin Dent. 2010;21(4):96-100.
  10. Nowak K, Ratajczak-Wrona W, Górska M, Jab?o?ska E. Parabens and their effects on the endocrine system. Mol Cell Endocrinol. 2018 Oct 15;474:238-251.
  11. Nair B. Final report on the safety assessment of Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate. Int J Toxicol. 2001;20 Suppl 3:23-50.
  12. Park YD, Jang JH, Park JE, Kim JH, Kim EC, Song YJ, et al. Analysis of parabens in dentifrices and the oral cavity. Biomed Chromatogr. 2014 Dec;28(12):1692-700.
  13. Jeng JH, Hsieh CC, Lan WH, Chang MC, Lin SK, Hahn LJ, et al. Cytotoxicity of sodium fluoride on human oral mucosal fibroblasts and its mechanisms. Cell Biol Toxicol. 1998 Dec;14(6):383-9.
  14. Camargo SE, Jóias RP, Santana-Melo GF, Ferreira LT, El Achkar VN, Rode Sde M. Conventional and whitening toothpastes: cytotoxicity, genotoxicity and effect on the enamel surface. Am J Dent. 2014 Dec;27(6):307-11.
  15. Tsay HJ, Wang YH, Chen WL, Huang MY, Chen YH. Treatment with sodium benzoate leads to malformation of zebrafish larvae. Neurotoxicol Teratol. 2007 Sep-Oct;29(5):562-9.
  16. Harvey PW, Everett DJ. Significance of the detection of esters of p-hydroxybenzoic acid (parabens) in human breast tumours. J Appl Toxicol. 2004 Jan-Feb;24(1):1-4.
  17. Ng CT, Yong LQ, Hande MP, Ong CN, Yu LE, Bay BH, et al. Zinc oxide nanoparticles exhibit cytotoxicity and genotoxicity through oxidative stress responses in human lung fibroblasts and Drosophila melanogaster. Int J Nanomedicine. 2017 Feb 28;12:1621-1637.