Teaching about Torques and Composite Movements through Examples in Orthodontics

Many life-sciences majors hope to pursue careers in dentistry. Introductory physics classes, including those designed for life-sciences majors, often lack curricular material with examples based on orthodontics, a branch of dentistry that deals with movement and alignment of teeth. A good understanding of forces and torques is important in orthodontics. A combination of different movements such as translation and rotations about the center-of-resistance (a concept equivalent to center-of-mass for constrained objects) is required to achieve the desired orthodontic results. To connect orthodontics to physics concepts, we developed curriculum discussing different orthodontic movements in the context of torques and forces, incorporating the physiological processes underlying orthodontic treatment. We developed interactive simulations for students to explore the main concepts associated with torque, such as the moment arm and line of action of forces. Students worked on visualizing the motion of teeth as a combination of translation and rotation. We also produced videos of interviews with an orthodontist discussing current orthodontic technology. This curriculum can be used as a model to integrate physics and health sciences concepts, thereby increasing class engagement by pre-health students.