Noise Reduction Using Active Vibration Control Methods in CAD/CAM Dental Milling Machines

Abstract

Used in close proximity to dental practitioners, dental tools and devices, such as hand pieces, have been a possible risk factor to hearing loss due to the noises they produce. Recently, additional technologies such as CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) milling machines have been used in the dental environment and have emerged as a new contributing noise source. This has created an issue in fostering a pleasant hospital environment. Currently, because of issues with installing and manufacturing noise-reducing products, the technology is impractical and insufficient relative to its costly nature. In this experiment, in order to create a safe working environment, we hoped to analyze the noise produced and determine a practical method to attenuate the noises coming from CAD/CAM dental milling machines. In this research, the cause for a noise and the noise characteristics were analyzed by observing and measuring the sound from a milling machine and the possibility of reducing noise in an experimental setting was examined using a noise recorded from a real milling machine. Since a milling machine generates noise mainly due to vibration of the dust collector, the possibility of reducing noise was examined by controlling vibration. This study was conducted to understand the cause for noise from the milling machine and verify the possibility of improving noise by a tactile transducer.

A User-Specific Approach for Comfortable Application of Advanced 3D CAD/CAM Technique in Dental Environments Using the Harmonic Series Noise Model

“…In our previous study [8], we obtained noise reduction of a CAD/CAM dental milling machine through the vibration control method. However, those results just indicated a decrease in noise levels.…”

“…Our previous study [8] demonstrated that noise reduction of CAD/CAM dental milling machines can be done through an active vibration control (AVC) method with tactile transducers. Earlier studies accomplished noise reduction through active noise control methods [9].…”

“…The results of the active cancellation procedure in our previous study [8] are shown in Table 1. Test results showed that the primary source of noise, dust collector vibrations, was effectively decreased through the anti-vibrations produced by the AVC method.…”

Application of Soundproofing Materials for Noise Reduction in Dental CAD/CAM Milling Machines

“…When observing a frequency spectrum of milling machine noise, there is a peak frequency which can explain the noise characteristics, although this may depend on the manufacturing company [11]. To apply effective noise control in this study, the peak frequency was discovered, and the frequency features of the milling machine noise were examined on the basis of the peak frequency.…”

“…Consequently, it is critical to identify the noise transmission paths and the causes of such noise in a milling machine [10]. Our previous study suggested an active noise control method by identifying the noise characteristics of the milling machine but also reported the disadvantage of having to generate the control sound depending on where the machine is installed [11].…”