Development of an ultra-miniaturized inertial measurement unit for jaw movement analysis during free chewing

Problem statement: Jaw movement analysis, as a clinical aid, can prov ide an objective basis for understanding and diagnosing jaw musculos keletal disorders. Therefore, the use and development of devices for quantitatively measuring and analyzing jaw movement have become more common and popular in the clinic. Many types of jaw tracking devices have been developed, but most of them are still not handy and easy to be used. Approach: To improve the handiness and utility of the jaw movement analysis devices, we developed a simple to be used jaw tracking prototype by using a new ultra-miniaturized Inertial Measurement Unit (I MU) named WB-3. The WB-3 IMU was composed by 3-axis gyroscope, 3-axis accelerometer and 3-aixs magnetometer, which can not only measure the acceleration and angular speed of jaw movement, but also can measure mouth opening angle. The IMU's extremely reduced weight and size allowed it to be easily adhered to mandible during normal tests without physical restriction to the subjects. A preliminary experiment for jaw movement analysis during free chewing of three types of food with different shapes and hardness was evaluated. A group of 15 healthy subjects aged from 21-36 years old kindly participated in the experiment. Results: The parameters of chewing time, chewing frequency, power spectrum density of jaw's angular speed and acceleration, cumulative di stribution function of jaw's acceleration and mouth opening angle were presented. The experimental results clearly showed that the subjects used less chewing time, less chewing frequency, less accelera tion cumulative distribution and energy to eat soft food; higher values were found in the case of hard food and there was no significant difference in mouth opening angle while eating these three foods. Conclusion: Our jaw movement analysis prototype using IMU WB-3 was proved to be a valid and handy method for jaw movement and pattern analysis which may be used clinically as an assista nt system for dental therapy.

[1]  Naoki Suzuki,et al.  Real-time mandibular movement analysis system using four-dimensional cranial bone model , 2006, Systems and Computers in Japan.

[2]  Akihiko Uchiyama,et al.  Real-time mandibular movement analysis system using four-dimensional cranial bone model , 2006 .

[3]  M Naeije,et al.  Biomechanics of the Human Temporomandibular Joint during Chewing , 2003, Journal of dental research.

[4]  Timothy S Miles,et al.  A simple and inexpensive system for monitoring jaw movements in ambulatory humans. , 2002, Journal of biomechanics.

[5]  Hiroshi Iseki,et al.  Development of the Ultra-Miniaturized Inertial Measurement Unit WB3 for Objective Skill Analysis and Assessment in Neurosurgery: Preliminary Results , 2009, MICCAI.

[6]  C.N. Riviere,et al.  Performance Envelope and Physiological Tremor in Microsurgery , 2006, Proceedings of the IEEE 32nd Annual Northeast Bioengineering Conference.

[7]  Salvatore Sessa,et al.  Waseda Bioinstrumentation System #3 as a tool for objective rehabilitation measurement and assessment - Development of the inertial measurement unit - , 2009, 2009 IEEE International Conference on Rehabilitation Robotics.

[8]  Robert B. McGhee,et al.  An extended Kalman filter for quaternion-based orientation estimation using MARG sensors , 2001, Proceedings 2001 IEEE/RSJ International Conference on Intelligent Robots and Systems. Expanding the Societal Role of Robotics in the the Next Millennium (Cat. No.01CH37180).

[9]  Masahiro Yamaguchi,et al.  A new tracking system of jaw movement using two magnets , 2002 .

[10]  W. T. Latt,et al.  Bandlimited Multiple Fourier Linear Combiner for Real-time Tremor Compensation , 2007, 2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[11]  Christopher J. Taylor,et al.  Medical Image Computing and Computer-Assisted Intervention – MICCAI 2009 , 2009, Lecture Notes in Computer Science.