Mouthguards vary in comfort, fit and protection
Pressure-formed, custom-made mouthguards are the best
Proform is the best material available
Mouthguards should be replaced every 1-2 years
Mouth-formed mouthguards are made of thermoplastic vinyl and are commonly referred to as "boil & bite" mouthguards. They are placed in boiling water, transferred to cold water and then adapted to the teeth.
They are found in most stores, however offer limited comfort because of the one size fits all approach.