Purpose: The essential function of mouthguards is protection against the effects of injuries sustained during sports activities. This purpose will be successfully achieved if appropriate materials ensuring sufficient reduction of the injury force are used for mouthguard fabrication. Objective: The objective of the study was to investigate the force reduction capability of selected materials as well as to identify which material reduces the impact force to the highest degree. Methods: The material for the study were samples of polymers (6 samples in total), obtained during the process of deep pressing (2 samples), flasking (3 samples) and thermal injection (1 sample), which were tested for impact force damping using an impact device – Charpy impact hammer. The control group comprised of the ceramic material samples subjected to the hammer impact. The statistical analysis applied in this study were one-way Welch ANOVA with post-hoc Games-Howell pairwise comparisons. Results: The test materials reduced the impact force of the impact hammer to varying degrees. The greatest damping capability was demonstrated for the following materials: Impak with 1:1 powder-to-liquid weight ratio polymerized with the conventional flasking technique, and Corflex Orthodontic used in the thermal injection technique of mouthguard fabrication. Conclusions: Impak with 1:1 weight ratio and Corflex Orthodontic should be recommended for the fabrication of mouthguards since they demonstrated the most advantageous damping properties.