The use of a dental ultrasonic descaler may be associated with biological hazards to structures within the oral cavity. Thermal hazards may result from either frictional contact between the oscillating probe and tooth or from absorption of acoustic energy within the tooth.
Transmission of ultrasound along the tooth may result in thrombogenic damage to nearby blood vessels. The vibrating probe tip may produce scratching of the tooth surface, and incorporation of oral bacteria within the aerosol generated by the instrument which may result in transmission of infected material. Damage to the ear may arise from the coupling of ultrasound to the bones of the skull via the tooth.
Furthermore the electro-magnetic field produced by these devices may interfere with cardiac pacemakers. It is the patient receiving treatment who is mainly exposed to these potential hazards. However, the clinician and his supporting staff may also be at risk.
During dental treatment, the oscillating tip of ultrasonic scaler will be in contact with the tooth. It may be possible that the tooth acts as a waveguide conducting the vibrational energy from the scaler toward the apex of the root. If sufficient energy reaches the root, then it could pose a thrombogenic hazard to the blood vessels passing through the apical foramen into the pulp. This may lead to a potential loss of tooth vitality.
A study conducted in vivo on mice to assess the effect of a wire vibrating at a frequency of 20 kHz placed against an intact blood vessel resulted in the production of platelet emboli and the formation of thrombi. This work was repeated with a commercially available ultrasonic scaler, which demonstrated similar findings. Thus, ultrasound transmissions into the tooth may result in potential damage to the structures such as blood vessels both within and around the teeth.