Ultrasonic Dental Scaler Performance Assessment with an Innovative Cavitometer

Problem statement: There is no specific instrument to test ultrasonic dental scalers used in dentistry. Approach: The aim of this research was to develop and test an innovative cavitometer for quantitative and automatic performance assessments of Ultrasonic Dental Scalers (UDS) through the acoustic emission produced by cavitation induced by the tip of the UDS ultrasonic transducer when immersed in aqueous solution. Firstly, an optimized acoustic emission sensor specifically for UDS ultrasonic transducers, software to process the acoustic emission sensor signal and to calculate a Figure of Merit (FM) and a hydraulic-pneumatic circuit were developed; these parts together constituted the cavitometer. To validate the developed cavitometer, two groups of UDS transducers were tested with the cavitometer and with one cleaning test; 48 units of the Jet1 UDS model and 12 units of the Jet2 model (Gnatus, Ribeirao Preto, Brazil) were tested. Sixteen assessments were carried out with each transducer, for a total of 768 measurements with Jet1 and 192 with Jet2. Spearman test was employed to observe correlations between the measurements from the different methods. Jet1 transducers were compared with Jet2 employing Student t test for cavitometer assessments and Mann Whitney U test for the cleaning test assessments. Results: Was found correlation between the cavitometer and cleaning results. The developed cavitometer detected a significant difference between average results for the two transducer groups (Jet1: 4.3±0.7 Vs Jet2: 6.2±0.5) and this was also observed for the cleaning test (Jet1: 7.0±0.8 Vs Jet2: 8.7±0.4) Conclusion: The results showed that the developed cavitometer is adequate for the UDS quantitative performance assessment, particularly for replacement of the cleaning test for industrial quality control.