Athletic Associations currently require the use of mouthguards only for ice hockey, lacrosse, field hockey and football.
However, Dental Associations recommend the use of a mouthguard for 29 sports/exercise activities. These include the four activities
already mentioned, plus acrobatics, basketball, boxing, discus throwing, gymnastics, handball, martial arts, racquetball, rugby,
shot putting, skateboarding, skiing, skydiving, soccer, squash, surfing, volleyball, water polo, weightlifting and wrestling.
Essentially, whenever there's a chance of contact with other players or hard surfaces, wearing a mouthguard makes sense.