how to choose mouth guards from store? as a of office clerk, I think there are some tips for you reference: 1, you should know the size of mouth guards that you want to purchase. 2, you should know the material of mouth guards, in general there are several material of MG: POE,EVA, and silicone, the safety of these mouth guards are tested. 3, the logo printing position, though now the ink safety of printing has been increased greatly, but there is trace unfriendly ingredient, so the safety of mouth guards with logo printed array is as following: only mouth guards box printed> inlay logo mouth guards(logo placed inside two layer of MG)> logo printed on the mouth guards itself. 4, mouth guards color, general, light color mouth guard is more safe than dark mouth guards.