Dynamic characterisation of teeth by laser vibrometry

摘要

The use of air compressed, high rotational velocity drill and of ultrasound devices in the dentist practice can cause pain for the patient and damage to the tooth structure.The authors, in this paper, have investigated the possible cause of these problems: the vibrations caused by the drill exciting the tooth. Particular attention has been dedicated to the frequency behaviour of teeth, in order to individuate their frequency resonances.A method for the investigation of human teeth dynamic response, in terms of natural frequencies and modal shapes has been proposed. Very short laser pulses have been used to excite teeth vibrations and a Scanning Laser Doppler vibrometer to measure thedynamic responses.An assessment of the amplitude of the characteristics of the excitation has been done using the theory of the impulse response function in such a way as to calculate the frequency response of the teeth. The results measured have been compared. Resultspermit to extract information extremely useful for the design of devices used in the dentist practice.