Stock ones shift and can cause injury; custom molded to teeth are safer and more comfortable for breathing/talking. Many teams recommend them. We got one for hockey; holds secure during hits. Alberta Dentures offers custom sports mouthguards in Calgary – durable materials, good ventilation, personalized fit https://albertadentures.com/service/custom-sports-mouthguards-in-calgary . Quick process. Check insurance – some cover protective appliances.