At the Biomechanics and Instrumentation Lab at the University of Victoria in Victoria, BC!

Collaborators: Bhavneet Bola, Jesse Knaggs

Principal Investigator: Christopher R. Dennison, PhD, PEng

Mouthguards are widely used in contact sports to mitigate orofacial injuries, yet there is currently no standardized method for evaluating their effectiveness. The project aim was to build a biomechanically accurate surrogate jaw model and experimental setup to simulate and measure impact forces during blunt-force trauma.

This project involved…

• designing and validating a biomechanically accurate 3D-printed human jaw surrogate and impact pendulum to evaluate the ability of commercial mouthguards to reduce orofacial impact forces.
• integrating high-frequency accelerometers into a modular dental model structure with a functional temporomandibular joint to replicate natural jaw motion.
• conducted standardized blunt-force impact testing using a custom pendulum system, comparing acceleration responses with and without mouthguard protection.
• acquired data using LabView, filtered in MATLAB per SAE J211 standards, and analyzed statistically to assess mouthguard’s effectiveness in reducing localized forces within the oral cavity.

SolidWorks assembly model of the maxilla and mandible, including the temporomandibular joint (TMJ). Accelerometers are seen in green.

This image showcases the head model the jaw is connected to. An example of the mouthguard loading on the jaw is shown.

Previous version of impact experiment setup: a high-speed camera was used to observe and verify whether the pendulum ball deflected to the right or left upon impact.

3D print of the jaw model with the accelerometers inserted. The maxilla and mandible are printed in ABS resin, and the TMJ is machined with aluminum metal.

Placement of the accelerometers inside of the mouth model. The maxilla was modified to ensure the accelerometers were fit tightly to reduce signal noise.

Final experimental setup deemed as repeatable per data analysis completed.

Repeatability of Experimental Model

During my time working in the lab, I implemented several design modifications to the maxilla surrogate model and the custom-built pendulum. Through making these modifications, we were able to achieve high repeatability of the impact testing experiment.

Experimental repeatability ensures consistent results across trials, allowing mouthguard presence to be the only varying factor and minimizing experimental error.

Some factors we considered during our repeatability studies:

• surrogate head alignment
• variance in acceleration values

Final data showcasing repeatability across 75 impacts for no mouthguard tests: