Continuous monitoring of pH and Eh in bacterial plaque grown on a tooth in an artificial mouth.

Apparatus which enables the simultaneous continuous monitoring of pH and Eh of bacterial dental plaque as it develops on a tooth surface in an artificial mouth is described. Details of the electrodes used, monitoring equipment, and culture conditions are given. Preliminary results are given showing the Eh and pH values of plaque produced in vitro to be in close agreement with readings reported for plaque in vivo. The effect of the incorporation of 1 per cent sucrose in the medium on these parameters is reported and a distinct inverse relationship between pH and Eh recorded.