You bet they are. A lost tooth must be re-implanted or false teeth made and fitted. Although easier to treat than a broken or fractured jaw, lost teeth are just as painful. A mouth guard is a piece of soft plastic shaped to fit inside the mouth, protecting the lips, cheeks, tongue and teeth and the jaw when they are hit by large object like a ball, or someone's elbow or head. You get what you pay for in terms of fit.
Some users complain that they are too wide in the back, making it hard to breath or talk.
Boil and Bite. A semi-custom fit can be made using a boil and bite model mouth guard. Hot water is used to soften the plastic and your child then bites into the guard, molding it to his or her teeth. A dentist makes the best fitting mouth guards in a dental office. Custom mouth guards are the best option if your child plays a number of sports each year or plays sports with continuous activity, like basketball or soccer.