Son HJ, et al. - Authors evaluated the differences in thickness of mouthguards that result from different groove shapes of ethylene vinyl acetate sheets used to make these appliances. They used a 3-dimensional printer to make the mouthguards and produced by softening 4-mm transparent circular sheets. They evaluated 4 different shapes of sheets: normal sheets, sheets with anterior V-shaped grooves, sheets with anterior A-shaped grooves, and sheets with posterior A-shaped grooves. The mouthguard thickness was not influenced by the presence of grooves on the sheets.