Journal of Dental Research, Vol 75, 1936-1941, Copyright © 1996 by International & American Associations for Dental Research Online Journals

ARTICLES

Protein characterization of fluorosed human enamel

J. T. Wright, S. C. Chen, K. I. Hall, M. Yamauchi and J. W. Bawden
Department of Pediatric Dentistry, School of Dentistry University of North Carolina at Chapel Hill 27599-7450, USA.

Despite extensive investigation, the development mechanism or mechanisms resulting in dental fluorosis are unknown. Several hypotheses suggest abnormal matrix synthesis, secretion, and delayed and/or defective matrix degradation with retention of enamel protein. The purpose of this study was to characterize the protein composition of fluorosed human enamel. Nine permanent moderately fluorosed (developed in a 3.2 ppm H2O area) and ten permanent normal control teeth (from individuals with < 0.2 ppm F in their drinking water) were evaluated. The enamel fluoride concentration, protein content, and amino acid composition were determined for each tooth. The enamel proteins were further characterized by gel electrophoresis and by Western blot analysis by means of polyclonal antibodies raised against recombinant amelogenin protein. Fluorotic enamel had significantly elevated (p = 0.0001) F levels compared with normal enamel (mean [F-] fluorosed = 431 ppm; mean [F-] control = 62 ppm). While there was a significantly greater protein content by weight in fluorosed enamel compared with normal enamel (mean fluorosed = 0.27%; mean control = 0.11%), the amino acid profiles were similar for fluorosed and normal enamel. Gel electrophoresis showed fluorosed enamel to have a greater diversity of primarily low-molecular-weight proteins compared with normal enamel. Western blot analysis did not indicate retention of amelogenin in either fluorosed or normal enamel. This investigation showed that the protein content of fluorosed enamel was greater than that of normal enamel; however, the amino acid compositions were similar for fluorosed and normal enamel. Furthermore, there does not appear to be retention of significant amounts of amelogenin in fully mature, moderately fluorosed human enamel. Although delayed removal of the enamel matrix proteins may play a role in the hypomineralization defects seen in fluorosed enamel, the majority of these proteins are absent in the mature tissue of these moderately fluorosed teeth.

This article has been cited by other articles:

				J.D. Bartlett, S.E. Dwyer, E. Beniash, Z. Skobe, and T.L. Payne-Ferreira Fluorosis: A New Model and New Insights J. Dent. Res., September 1, 2005; 84(9): 832 - 836. [Abstract] [Full Text] [PDF]

				T. A. Marshall, S. M. Levy, J. J. Warren, B. Broffitt, J. M. Eichenberger-Gilmore, and P. J. Stumbo Associations between Intakes of Fluoride from Beverages during Infancy and Dental Fluorosis of Primary Teeth J. Am. Coll. Nutr., April 1, 2004; 23(2): 108 - 116. [Abstract] [Full Text] [PDF]

				T. Aoba and O. Fejerskov DENTAL FLUOROSIS: CHEMISTRY AND BIOLOGY Crit. Rev. Oral. Biol. Med., March 1, 2002; 13(2): 155 - 170. [Abstract] [Full Text]