Magnetostrictive calibration of a precision optical measurement device for studies of tooth eruption.

In order to calibrate a precision-measuring instrument for studies of tooth eruption, a calibration device capable of repositioning an optical grating in steps accurate to at least 0.02 microns was required. At this level, piezoelectric and similar pushers encounter problems. A new calibration device based on the magnetostrictive properties of nickel was developed. Accuracy better than 0.02 microns was verified by relating its movements to the wavelength of the green line of mercury, and the device was successfully used to calibrate the instrument for establishing tooth position. Magnetostriction offers a way to calibrate precision measurement instruments for other applications.