The pH of human crevicular fluid measured by a new microanalytical technique

In physiological and pathological conditions, the pH of the crevicular fluid may play a significant role on the structure and function of the gingival crevice. In the present investigation the pH of human crevicular fluid was determined by a new microanalytical technique. The fluid was collected in 32 sites (19 patients) with capillary tubes. The tip of a double barreled, neutral carrier based microelectrode, highly selective for H + ions was introduced directly into the capillary tubes containing either the samples or the reference solutions. In each sampling site, the GI and the crevicular fluid volume were recorded and correlated with the pH. As the inflammation increased, an elevation of pH from 6.90 to as much as 8.66 was observed. These values have been measured at 20°C in absence of CO 2 . Whether this increase is due to the bacterial flora or to any metabolic activity in the crevice area is not clear at the moment.