Acid-Base Properties of Human Gingival Crevicular Fluid

Abstract

The pH of human gingival crevicular fluid (GCF) has been reported by many authors to be very alkaline (pH 7.5 - 8.7). This alkalinity could be explained, at least partially, by the fact that all measurements were performed either at low Pco, or in the absence of CO ₂. Therefore, we set up a procedure which allows for measurement of the pH of GCF samples from single inflamed sites at controlled Pco₂. At a Pco₂ of 4.7 kPa (= 35 mmHg) and at 37 °C, the pH was 7.96 ± 0.10 (SEM, n = 9), a value which differs significantly from the value of 8.38 ± 0.09 measured in the absence of CO₂ in the same samples. The non-bicarbonate buffer value of the sample determined by CO ₂ titration was 6.0 slykes. It is because this value is low that pH varies so greatly with Pco ₂. At physiological Pco ₂, the total buffering power becomes very high above pH 8.0, because of the high bicarbonate concentration.

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References

Ammann, D. ; Lanter, R.A. ; Schulthess, P. ; Shijo, Y. ; and Simon, W. (1981): Neutral Carrier Based Hydrogen Ion Se

lective Microelectrode for Extra- and Intracellular Studies , Analyt Chem 53:2267-2269.

Bang, J. and Cimasoni, G. (1971): Total Protein in Human Crevicular Fluid, J Dent Res 50:1683.

Bickel, M. and Cimasoni, G. (1985): The pH of Human Crevicular Fluid Measured by a New Microanalytical Technique, J Periodont Res 20:35-40.

Bickel, M. ; Cimasoni, G. ; and Andersen, E. (1985): Flow and Albumin Content of Early (Pre-inflammatory) Crevicular Fluid from Human Subjects, Arch Oral Biol (in press).

Borden, S.M. ; Golub, L.M. ; and Kleinberg, I. (1977): The Effect of Age and Sex on the Relationship Between Crevicular Fluid Flow and Gingival Inflammation in Humans, J Periodont Res 12:160-165.

DAVENPORT, H.W. (1958): The ABC of Acid-Base Chemistry, 4th ed. Chicago: The University of Chicago Press, pp. 39-40. IZUTSU, K.T. (1981): Theory and Measurement of the Buffer Value of Bicarbonate in Saliva, J Theoret Biol 90:397-403.

Kaiser, D. ; Songo-Williams, R. ; and Drack, E. (1974): Hydrogen Ion and Electrolyte Excretion of the Single Human Sweat Gland, Pflügers Arch 349:63-72.

Kleinberg, I. and Hall, G. (1969): pH and Depth of Gingival Crevices in Different Areas of the Mouths of Fasting Humans, J Periodont Res 4:109-117.

10.

Mettraux, G.R. ; Gusberti, F.A. ; and Graf, H. (1983): Oxygen Tension (pO2) in Untreated Human Periodontal Pockets, J Periodont 55:516-521.

11.

Munoz, J.L. ; Deyhimi, F. ; and Coles, J.A. (1983): Silanization of Glass in the Making of Ion-sensitive Microelectrode, J Neurosci Meth 8:231-247.

12.

Siggaard-Andersen, O. (1926): The CO2 Equilibration Curve of Plasma. In: The Acid-Base Status of the Blood, 4th ed. Copenhagen : Munksgaard, pp. 41-44.

13.

Stephen, K.W. ; McCrossan, J. ; and Mackenzie, D. (1980): Factors Determining the Passage of Drugs from Blood into Saliva, J Clin Pharmacol 9:51-55.

14.

Van Slyke, D.D. (1922): On the Measurement of Buffer Value and on the Relationship of Buffer Value to the Dissociation Constant of the Buffer and the Concentration and Reaction of the Buffer Solution, J Biol Chem 52:525-570.

15.

Walker, J.L., Jr. (1971): Ion Specific Liquid Ion Exchanger Microelectrodes , Analyt Chem 43:89A-93A.

16.

Woodbury, J.W. (1965): Regulation of pH. In: Physiology and Biophysics, T.C. Ruch and H.D. Patton , Eds., Philadelphia: W.B. Saunders Co.