Hi my 13 year old son has just got twin block braces today but am needin a little advice dentist told us he must wear them at all times apart from eating but he has been told to wear them whilst sleeping however the bottom brace comes off very easily when its knocked with his tounge am just wondering if anyone else has experienced this as im a little uncomfortable letting him wear it whilst sleeping due to the easiness it comes off when knocked therefore am worried it could choke him whilst he sleeping anyone any advice ??