Human factors in the measurement of the masseteric silent period

Human variability in the measurement of the masseteric silent period (SP) was quantified. There were significant differences among (1) observer groups (technicians and dental students), (2) individual observers, (3) repeated measures of the same SP, and (4) trials. No significant observer bias was found. SP's were significantly longer at an inter-incisal distance of 10 mm (48.8 +/- 5.4 ms) than at 14 or 19 mm (44.7 +/- 9.8 ms, 44.5 +/- 6.5 ms).