An ultrasonic surgical apparatus and method of use including a signal generator outputting a drive signal having a frequency, an oscillating structure, receiving the drive signal and oscillating at the frequency of the drive signal, a bridge circuit, detecting the mechanical motion of the oscillating structure and outputting a signal representative of the mechanical motion, and a microcontroller receiving the signal output by the bridge circuit, the microcontroller determining an instantaneous frequency at which the oscillating structure is oscillating based on the received signal, and comparing the instantaneous frequency to a known frequency value and estimating a temperature of the oscillating structure based on the comparison.
