Possible Physico-Chemical Processes in Human Dentin Caries

Abstract

This study correlated ultrastructural observations on the presence of beta-tricalcium phosphate (β-TCP) in arrested dentin caries with physico-chemical observations on the in vitro formation of Mg-substituted β-TCP. The ultrastructural studies were made using high-resolution transmission electron microscopy (TEM) with the capability of microdiffraction and microanalysis on sites less than 10 nm in diameter. Mg-substituted β-TCP was obtained, by a precipitation method, from solutions with Mg/Ca molar ratios of 5/95 and higher. Such correlation led to the postulation of a possible chronological sequence of physico-chemical events occurring at the crystal level during the progress and arrest of caries in human dentin. It is suggested that the initial mechanism for the observed occurrence of large crystals of Mg-substituted β-TCP and of apatite in the tubule lumen is due to the dissolution of the dentin mineral (a CO₃- and Mg-rich calcium OH-apatite) and reprecipitation of Mg-substituted β-TCP, followed by that of CO₃- and Mg-poor apatite.

Get full access to this article

View all access options for this article.

References

Bradford, E.W. (1960): The Dentine, a Barrier to Caries, Br Dent J 109:387-398.

Daculsi, G. ; Kerebel, B. ; LE Cabellec, M.T. ; and Kerebel, L.M. (1979): Qualitative and Quantitative Data on Arrested Caries in Dentine, Caries Res 13:190-202.

Frank, R.M. and Voegel, J.C. (1980): Ultrastructure of the Human Odontoblast Process and its Mineralization during Dental Caries, Caries Res 14:367-380.

Hawkinson, R.W. and Eisenmann, D.R. (1983): Electron Microscopy of Dentinal Sclerosis in the Enamel Free Region of the Rat Molar, Arch Oral Biol 28:409-414.

LeGeros, R.Z. (1967): Crystallographic Studies on the Carbonate Substitution in the Apatite Structure, PhD Thesis, New York University .

LeGeros, R.Z. (1974): Variations in the Crystalline Components of Dental Calculus. 1. Crystallographic and Spectroscopic Methods of Analysis, J Dent Res 53:45-50.

LeGeros, R.Z. (1981): Apatites in Biological Systems, Prog Cryst Growth Charact 4:1-45.

LeGeros, R.Z. (1984): Incorporation of Magnesium in Synthetic and Biological Apatites. In: Tooth Enamel IV, R.W. Fearnhead and S. Suga , Eds., Amsterdam: Elsevier Science Publishers , pp. 32-36.

LeGeros, R.Z. and LeGeros, J.P. (1984): Phosphate Minerals in Human Tissues. In: Phosphate Minerals , J. Nriagu and P. Moore , Eds., Berlin: Springer-Verlag, pp. 351-385.

10.

LeGeros, R.Z. ; Klein, E. ; and Miravite, M.A. (1974): Biological Whitlockites, Occurrence and Formation , IADR Progr & Abst 53: No. 199.

11.

LeGeros, R.Z. and Tung, M.S. (1983): Chemical Stability of Carbonate- and Fluoride-containing Apatites, Caries Res 17 :419-429.

12.

Lester, K.S. and Boyde, A. (1968): Some Preliminary Observations on Caries (Remineralization) Crystals in Enamel and Dentin by Surface Electron Microscopy, Virchows Arch A Path Anat 344:196-212.

13.

Newesely, H. (1965): Über die Existenzbedingungen von Oktacalcium phosphat, Whitlockit und Carbonatoapatit. Beitrag zur Kristallchemie Biologischer Hartsubstanzen, D Zahnärztl Z 20 :753-766.

14.

Rowles, S.L. (1967): The Precipitation of Whitlockite from Aqueous Solutions. Coll Int sur les Phosphates Mineraux solides, Vol. 1, CNRS, Toulouse, pp. 151-155.

15.

Suga, S. ; Soejima, H. ; and Tanaka, Y. (1967): Electron Probe X-ray Tissues, J Dent Res 46:1251-1252.

16.

Takuma, S. ; Ogiwara, H. ; and Suzuki, H. (1975): Electron Probe and Electron Microscope Studies of Carious Dentinal Lesions with Remineralized Surface Layer, Caries Res 9:278-285.

17.

Takuma, S. ; Sunohara, H. ; Watanabe, H. ; and Yama, K. (1969): Some Structural Aspects of Carious Lesions in Human Dentine, Bull Tokyo Dent Coll 10:173-181.

18.

Tronstad, L. (1973): Scanning Electron Microscopy of Attrited Dentinal Surfaces and Adjacent Dentine in Human Teeth, Scand J Dent Res 81:112-122.

19.

Vahl, J. ; Hohling, H.J. ; and Frank, R. (1964): Elektronenstrahlenbengung an rhombohedrisch aussehenden Mineralbildungen in kariosem Dentin, Arch Oral Biol 9:315-320.