Measurement System for Human Lateral Mandibular Forces

Lateral mandibular movement is essential for grinding previously ingested food. By measuring the maximum lateral force of the mandible, it is possible to quantify the functionality of this important movement. However, state-of-the-art force sensors utilize the force application through the teeth, causing unknown measurement uncertainties, and, thus, making them unsuitable for qualitative measurements. We present a lateral force measurement system with a nominal force of 200 $\mathrm{N}$ and an accuracy of 0.5 %, which is capable of measuring protrusive forces as well. The connection between the jaw and the measuring system is established by a mandibular brace, which is located under the subject's jaw. The brace is interchangeable and can be customized for each individual subject to ensure optimal force application. A three-dimensional force sensor measures forces of the mandible in every translational direction. The measurement system is validated with a study of eight subjects. The maximum measured isometric forces of the mandible are 31.47 $\pm\ 11.00\ \mathrm{N}$ in lateral left direction, 37.32 $\pm\ 22.10\ \mathrm{N}$ in lateral right direction, and 82.96 $\pm\ 16.14\ \mathrm{N}$ in protrusive direction. The system builds a promising basis for measuring a variety of mandibular force parameters, allowing a deeper insight into the subject's masticatory system.