An in-dwelling electrode for in-vivo measurement of the pH of dental plaque in man.

A system for the measurement of plaque pH in vivo has been developed, using an in-dwelling miniature glass electrode. The reliability of the electrode and the closeness of the experimental conditions to natural ones compared favourably with previous techniques for measuring plaque pH. The effect on plaque pH of sucrose and saccharin rinses, and a chlorhexidine mouthwash were studied. Continuous small, rapid fluctuations in the pH of both stimulated and resting plaques were consistently observed and larger changes of pH were noted on opening the mouth and swallowing.