Aim: The study aimed to evaluate the effects of an electric toothbrush with vibrational frequencies of 125 and 150 Hz on the changes in temperature of the pulpal chamber. Materials and methods: A total of 30 extracted teeth were included in the study which were divided into two groups I and II comprising 15 teeth each to which mechanical vibration of 125 and 150 Hz, respectively was applied through the electric toothbrush for one minute per tooth. The temperature of the pulpal chamber was measured using a J-type thermocouple with a 0.36-inch diameter attached to a data recorder. The temperatures of the pulp chamber in both groups I and II were measured at T0 where no application of mechanical vibration onto the teeth was done and at T1 where the mechanical vibration of 125 and 150 Hz was applied onto the teeth, respectively using an electric toothbrush. The data was recorded and statistically analyzed. Results: The mean difference in temperature from T0 to T1 in group I was 0.37° ± 0.27° and that of group II was 0.36° ± 0.23°, respectively. When the temperature of the pulp chamber from T0 to T1 between both groups was compared, it did not show any statistically significant difference (p = 0.94). Conclusion: The mechanical vibrations of 125 and 150 Hz through the electric toothbrush did not have any significant effect on the thermal changes of the pulp chamber. Clinical significance: One of the most important applications of mechanical vibrations in orthodontics is to accelerate the rate of orthodontic tooth movement. However, evaluation of the changes in the temperature of the pulpal chamber due to its application is equally important. The establishment of a balance is much required wherein tooth movement can be achieved without compromise.