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|Title:||Reducing the noise from dental handpieces with adaptive filtering (Abstract)|
|Publisher:||International Association for Dental Research (IADR)|
|Citation:||Journal of Dental Research, 87, (1): (Special Issue C), pp. 93 - 93, (2008)|
|Abstract:||Objective: To develop a system to reduce the patient's discomfort and provide hearing protection for the clinical team from the noise from dental handpieces. The specific aim of this part of the study was to reduce the handpiece noise in the frequency range from 2.5kHz to 11kHz by at least 6 dB. This would mean that the power of the noise would be reduced to only a quarter of its original value so the frequency would then be barely audible against background sound. Method: Five sound recordings were made of five dental air turbine handpieces in use with different amounts of loading: no load, 1N, 2N and 2.5N according to BS EN ISO 7785-1. The sound recordings were analysed using FFT power spectral density plots in the Matlab Signal Processing Tool (SPT). A Normalised Least Mean Square (NLMS) adaptive filter algorithm was applied to the recordings. Comparisons were made between the original recordings and the filtered recordings. Results: Five air turbine handpieces were tested and sound recordings at the four different loads were recorded and analysed. The application of adaptive filtering brought about noise reduction in each case with a maximum noise reduction of the sound peak of 27dB. For each test the noise reduction was always greater than 6dB and was statistically significant (p<0.001) for each handpiece at each loading condition. Conclusions: Adaptive filtering can be used to specifically reduce the unpleasant noise from dental air turbine handpieces without removing other background sounds. Supported by W&H.|
|Appears in Collections:||Dept of Mechanical Aerospace and Civil Engineering Research Papers|
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