Abstract
Since a considerable amount of the world population is exposed to high doses of fluoride, it is of special concern to investigate its action mechanisms during dental enamel development. In this study, the toxicity of fluoride in ameloblasts during enamel development was evaluated by means of ultrastructural morphometric analysis. A total of 18 male Wistar rats were distributed into three groups. In Group I, the animals received deionized drinking water ad libitum (negative control) and in Groups II and III, they received sodium fluorided (NaF) drinking water at doses of 7 and 100 ppm ad libitum, respectively, for 6 weeks. Morphometric data were expressed as volume density of the most significant organelles present in the secretory and maturation phases of amelogenesis such as RER, granules, lysosomes, phagic vacuoles, microfilaments and mitochondria. The results showed that the volume density of mitochondria in the 100 ppm experimental group was 29% (P < 0.05) higher than the control group in secretory ameloblasts. No remarkable differences were found in maturation ameloblasts for all organelles evaluated. Taken together, these data indicate that NaF at high doses is able to induce cellular damage in secretory ameloblasts, whereas no noxious effect was observed during maturation stage of amelogenesis as depicted by ultrastructural analysis.
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs10735-006-9065-2/MediaObjects/10735_2006_9065_Fig1_HTML.jpg)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs10735-006-9065-2/MediaObjects/10735_2006_9065_Fig2_HTML.jpg)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs10735-006-9065-2/MediaObjects/10735_2006_9065_Fig3_HTML.jpg)
![](http://media.springernature.com/m312/springer-static/image/art%3A10.1007%2Fs10735-006-9065-2/MediaObjects/10735_2006_9065_Fig4_HTML.jpg)
Similar content being viewed by others
References
Anuradha CD, Kanno S, Hirano S (2001) Oxidative damage to mitochondria is a preliminary step to caspase-3 activation in fluoride-induced apoptosis in HL-60 cells. Free Radic Biol Med 31:367–373
Bartlett JD, Dwyer SE, Beniash E, Skobe Z, Payne-Ferreira TL (2005) Fluorosis: a new model and new insights. J Dent Res 84:832–836
Chen J, Chen X, Yang K, Xia T, Xie H (2002) Studies on DNA damage and apoptosis in rat brain induced by fluoride. Zhonghua Yu Fang Yi za Zhi 36:222–224 (Article in Chinese)
Denbesten PK (1999) Mechanism and timing of fluoride effects on developing enamel. J Public Health Dent 59:247–251
DenBesten PK, Yan Y, Featherstone JD, Hilton JF, Smith CE, Li W (2002) Effects of fluoride on rat dental enamel matrix proteinases. Arch Oral Biol 47:763–770
Eisenmann DR, Ashrafi S, Zaki AE (1982) Multi-method analysis of calcium localization in the secretory ameloblast. J Dent Res Spec No 1555–62
Fejerskov O, Josephen K, Larsen MJ, Thylstrup A (1980) Cytological features of rat ameloblasts following long-term fluoride exposure. Carie Res 14:181–182
Ghosh D, Das Sarkar S, Maiti R, Jana D, Das UB (2002) Testicular toxicity in sodium fluoride treated rats: association with oxidative stress. Reprod Toxicol 16:385–390
Josephen K, Fejerskov O (1977) Ameloblast modulation in the maturation zone of the rat incisor enamel organ. A light and electron microscopy study. J Anat 124:45–70
Kruger BJ (1968) Ultrastructural changes in ameloblasts from fluoride treated animals. Arch Oral Biol 13:969–977
Kubota K, Lee DH, Tsuchiya M, Young CS, Everett ET, Martinez-Mier EA, Snead ML, Nguyen L, Urano F, Bartlett JD (2005) Fluoride induces endoplasmic reticulum stress in ameloblasts responsible for dental enamel formation. J Biol Chem 280:23194–23202
Li Y, Decker S, Yuan ZA, Denbesten PK, Aragon MA, Jordan-Sciutto K, Abrams WR, Huh J, McDonald C, Chen E, MacDougall M, Gibson CW (2005) Effects of sodium fluoride on the actin cytoskeleton of murine ameloblasts. Arch Oral Biol 50:681–688
Lyaruu DM, Bervoets TJ, Bronckers AL (2006) Short exposure to high levels of fluoride induces stage-dependent structural changes in ameloblasts and enamel mineralization. Eur J Oral Sci 114:111–115
Matsuo S, Kiyomiya K, Kurebe M (1998) Mechanism of toxic action of fluoride in dental fluorosis: whether trimeric G proteins participate in the disturbance of intracellular transport of secretory ameloblast exposed to fluoride. Arch Toxicol 72:798–806
Mornstad H, Hammarstrom L (1978) Morphologic changes in the rat enamel organ following a single intraperitonial injection of sodium fluoride. Scand J Dent Res 86:211–220
Pergolizzi S, Santoro A, Santoro G, Trimarchi F, Anastaso G (1995) Enamel fluorosis in rat’s incisor: S.E.M. and T.E.M. investigation. Bull Group Int Rech Stomatol Odontol 38:95–105
Reinolds ES (1963) The use of lead citrate at pH as an electron opaque stain in electron microscopy. J Ultrastruc Res 17:208–222
Ribeiro DA, Marques ME, de Assis GF, Anzai A, Poleti ML, Salvadori DM (2004) No relationship between subchronic fluoride intake and DNA damage in Wistar rats. Caries Res 38:576–579
Robinson C, Connell S, Kirkham J, Brookes SJ, Shore RC, Smith AM (2004) The effect of fluoride on the developing tooth. Caries Res 38:268–276
Smith CE, Nanci A (1989) A method for sampling the stages of amelogenesis on mandibular rat incisors using the molars as a reference for dissection. Anat Rec 224:292–316
Smith CE, Nanci A, Denbesten PK (1993) Effects of chronic fluoride exposure on morphometric parameters defining the stages of amelogenesis and ameloblast modulation in rat incisor. Anat Rec 237:243–258
Ten cate AR (1998) Oral histology: development, structure and funcion. 5th edn. Mosby-Year book Inc. St. Louis, USA
Walton RE, Eisenmann DR (1974) Ultrastructural examination of various stages of amelogenesis in the rat following parenteral fluoride administration. Arch Oral Biol 8:171–182
Warshawsky H, Moore G (1967) A technique for the fixation and decalcification of rat incisors for electron microscopy. J Histochem Cytochem 15:542–549
Weibel ER, Kistler GS, Scherle WF (1970) Practical stereological methods for morphometric cytology. WB Saunders Company, pp 58–82
World Health Organization (WHO) (1994) Available from:http://home.iae.nl/users/lightnet/health/fluoride.htm. Accessed July 17, 2006
Zhang Y, Yan Q, Li W, DenBesten PK (2006) Fluoride down-regulates the expression of matrix metalloproteinase-20 in human fetal tooth ameloblast-lineage in vitro. Eur J Oral Sci 114:105–110
Zhou R, Zaki AE, Eisenmann DR (1996) Morphometry and autoradiography of altered rat enamel protein processing due to chronic exposure to fluoride. Arch Oral Biol 41:739–747
Acknowledgements
This work was supported by CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) Grant number 130155/00-4 and FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) Grant number 99/07035-5, Brazil. Our thanks are extended to Professor Elliot W. Kitajima—ESALQ-USP for his assistance and the use of the transmission electron microscopy.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ribeiro, D.A., Hirota, L., Cestari, T.M. et al. Ultrastructural morphometric analysis of ameloblasts exposed to fluoride during tooth development. J Mol Hist 37, 361–367 (2006). https://doi.org/10.1007/s10735-006-9065-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10735-006-9065-2