Ultrasonic Scaling Tip Movements Investigated with a Scanning Laser Vibrometer

Objectives: Previous research has shown that ultrasonic scalers change their vibrational behaviour when operated at different generator power settings. The aim of this study was to investigate differences in displacement amplitude values when various designs of ultrasonic scaler tips are operated under a range of operating conditions. Methods: A piezoelectric (EMS Piezon P) and a magnetostrictive (FSI-SLI-10S) probe were operated under three different power settings. Recordings were taken using a Scanning Laser Vibrometer. Probes were operated without loading in air, under flowing water (water flow rate: 28.5 ml/min) and in a water bath with no water flowing over the probes from the generator. Results: Under all conditions tested the EMS Piezon P tip showed two nodal points occurring along the probe, whilst the FSI-SLI-10S tip only had one. Water flowing over the tips resulted in the smallest observed displacement amplitude values. Both types of probes operated at low and medium generator power settings resulted in maximum displacement amplitude values when immersed in water. At high generator power settings in water displacement amplitude values are slightly smaller than when the probe was operated in air. Conclusion: The structure of the ultrasonic probe including cross-section, shape and length is crucial in terms of maximum vibration displacement amplitude values. Slim designs result in higher values than beaver-tale shaped tips. Under flowing water, tip vibration displacement amplitude is minimal whereas when immersed in water, displacement amplitudes are increased at high generator power settings.

This work is supported by a project grant from the EPSRC (EP/C536894/1).