Sport mouth guard
You should consider wearing a mouth guard to protect your teeth during vigorous physical activities. For teenagers, until they have fully grown adult teeth, a mouth guard may need to be remade annually.
Nightguard / Occlusal splint
If you are a bruxer (grinder) or a clencher, who worries about teeth wear, or if you are suffering from the side effects from bruxing (grinding) or clenching (eg. stiff neck, headache in the forehead, cheek muscle aches), having a nightguard can be a solution for you. It requires two visits. There are a range of designs (eg. ball clasps, double layer) and can be fitted either to upper teeth or to lower teeth.