Physics Doesn't Bite—A Simple Experiment for Introducing Biomechanical Operational Principles of the Temporomandibular Joint

Biophysics is rarely mentioned as one of the most useful parts of dental and medical students' curricula. However, with the growing complexity of tools and methods used in diagnostics and therapy, the knowledge of their physical foundations becomes important and helps with choosing the optimal solutions for both, a patient and a doctor. The aim of the proposed activity is to develop students' intuition about simple physical models that help with understanding fundamental properties of temporomandibular joint (TMJ). A simple device, which allows for bite force measurement, is proposed. It is based on beam bending and a strain gauge Wheatstone bridge circuit mounted on two connected arms: the stiff one and the more elastic one. Linear regression is the only mathematical concept needed for understanding the physical background of the proposed activity. During the proposed activity—measuring of bite force for incisors, premolars, and molars—students are confronted with basic concepts, such as lever, torque, electrical circuit, calibration curve. By utilizing a simple idea, instead of a commercially available device, students can understand where the data come from. Proposed system delivers physiologically reasonable results.