High impact energy absorption is an essential property for mouthguard materials. Purpose: Compare the impact test performance of three mouthguard materials at two different loading speeds. Methods: Three mouthguard materials were selected: ethylene vinyl acetate (EVA, T&S Dental and Plastics, Myerstown, PA), which served as the control; ProForm (Dental Resources Inc, Delano, MN), another commercial ethylene vinyl acetate thermoplastic material; and Polyshok (Sportsguard Laboratories, Kent, OH), a new ethylene vinyl acetate product containing polyurethane. Test specimens of approximately 3 inch x 3 inch x 4 mm dimensions were loaded at 5 mph (miles per hour) and 10 mph by a 0.5-inch diameter indenter that contained a force transducer (Dynatup Model 9250 HV, Instron Corp, Canton, MA). The energy absorption during the impact process was determined from the area under the force-time curve, using computer software with the testing apparatus. Results were compared statistically using ANOVA and the Tukey multiple range test. Results: Total energy absorption (mean ± standard deviation for N = 5), normalized to specimen thickness, for the 10 mph loading speed was as follows (ft·lb/inch): EVA: 188.9 ± 43.4; ProForm: 77.8 ± 10.7; Polyshok: 178.4 ± 41.2. This normalized energy absorption was not significantly different for EVA and Polyshok, but was significantly higher (p < 0.01) than that for ProForm. Most EVA specimens did not puncture, whereas the opposite behavior was found for ProForm; no Polyshok specimens punctured. ProForm is completely ruptured approximately 11 ms after impact, while EVA and Polyshok continue to stretch for up to 30 ms. Conclusions: With this impact test, the energy absorption characteristics of Polyshok and EVA are very similar and much greater than that of ProForm. The ability of Polyshok to completely withstand puncturing is an advantageous feature. Future impact testing of these materials will utilize loading with an appropriate backing material.