Patent ID: 6786732
Filing Date: 2004-09-07
Classification: A46B

Abstract:
A method of monitoring the position of a toothbrush relative to teeth of a subject, the method comprising:providing a toothbrush having a first position sensor, the first position sensor at least being sensitive to changes in position and orientation; providing a second position sensor in fixed positional relationship to the teeth, the second position sensor being sensitive to changes in position and orientation; transmitting the output of the first position sensor and second position sensor to a processing apparatus; comparing via the processing apparatus the two sensor outputs to monitor the position of the toothbrush relative to the teeth over a period of time; locating a third position sensor in turn in a known positional relationship to the second position sensor and at least four locations on or in fixed relationship to the teeth, and comparing the locations to corresponding positions of a computer model to derive a transformation between a reference frame of the computer model and a reference frame of the second position sensor.