Citadel Mouthguard Study

Title: Citadel Mouthguard Study

Abstract: The purpose of this project is to develop a testing protocol to establish standards for mouthguards. This interim report reviews the progress made on the project.

Study Design: A fully instrumented pendulum has been developed to impact surrogate teeth, conducted preliminary testing on four types of mouthguards with piezoelectric ceramic discs and are determining the optimum material for the surrogate dentition to give both precision and biofidelity.

Materials and Methods: We have constructed a pendulum impacting device using half-inch steel rods clamped together and cross-braced to minimize vibrations. The pendulum rod is a ¼-20 threaded rod that is 34.4 cm long with a mass of 64 grams. The threading allows us to adjust the length of the pendulum and then hold the length constant while taking data. The “hammer” (pendulum weight) was machined from a 2.5 cm diameter brass rod. One end of the hammer is conical with a slightly rounded tip that is 5 mm in diameter. That size was chosen so that the force exerted by the pendulum can be directed to one tooth, and the experiment then measures how the mouthguard spreads the force over the neighboring teeth. In operation, the pendulum rod starts horizontal with the hammer resting on a spring loaded platform that is activated by pulling a string. This device releases the pendulum with no initial velocity.

We have taken pendulum collision data on three very different mouthguards. These were: 1) a one size fits most mouthguard, 2) an EVA (Ethyl Vinyl Acetate) thermal formed mouthguard, and 3) a mouthguard with external lip protection. In each experiment, the mouthguard was placed on a dental stone cast of the maxillary teeth while the mandibular teeth rested on top of the mouthguard to hold it in place. Both sets of teeth were mounted in a dental articulator which allows the castings to rotate about one horizontal axis. For mouthguards 1) and 2), several teeth were broken in each of the four tests. For the third mouthguard, no teeth were damaged in the two tests. The outcome of these tests convinced us that we need to rethink the cast teeth models we are using in this experiment. The dental stone will be replaced with a more robust composition and commercially available dental models will also be tested.