There are a few key reasons why mouthguards are recommended or required for certain sports:

1. Protection against oral injuries – Mouthguards help cushion and protect the teeth, lips, cheeks, and jaw from impacts and blows that can occur in contact and collision sports. This helps prevent dental injuries like chipped, broken, or knocked-out teeth.

2. Reducing concussion risk – Some studies have shown that mouthguards can help absorb and distribute the forces from impacts to the head, potentially reducing the risk or severity of concussions.

3. Preventing soft tissue injuries – Mouthguards can help prevent lacerations, bruises, and other injuries to the tongue, lips, and inside of the cheeks from teeth striking them during impacts.

4. Compliance with sports rules – Many organized sports, especially youth and high school sports, require the use of mouthguards for certain activities like football, hockey, boxing, martial arts, and others. This is to help protect the safety of the athletes.

So in summary, mouthguards serve as important protective equipment to help safeguard the teeth, jaw, and soft oral tissues from the impacts and collisions that can occur in many popular sports. Their use is recommended by dental and sports medicine professionals.