The effect of rate of increase of electrical current on the sensation thresholds of teeth.

The effect of the rate of increase of electrical current during stimulation of human teeth was examined on clinically sound upper anterior teeth. The teeth were stimulated with a current of 10 msec duration at a frequency of 50 Hz. Eight different rates of current increase were used, viz.: 1, 2, 3, 4, 5, 6, 7, and 8 mu a/sec. The results showed that there was a linear relationship between the sensation threshold and the rate of current increase, and that the threshold increased significantly as the rate of current rise increased. Slowly increasing current gave more accurate and reproducible results than did rapidly increasing current, and a rate of 2 mu a/sec was found to be appropriate for clinical pulp-testing.