Is it as simple as it seems?

If blows to the jaw transfer force to the skull, or if having a chinstrap on a helmet helps transfer energy to the skull in a collision, what could be the resistance to wearing custom mouthguards?

"It’s a device, Maher said, that’s simple and effective—two small pieces of acrylic that fit over the back four teeth of each side of the lower jaw, linked by a thin ‘‘lingual bar’’ that rests behind the front teeth and allows better breathing and communication than the conventional wraparound mouth guard.

Maher’s mouth guard brings the lower jaw slightly forward, moving the condyle (the nobby tip of the jaw) to rest against a slightly thicker portion of the skull, thereby providing more cushioning. The mouth guard also ensures that the condyle does not slip off the thin disk of cartilage that is supposed to sit on top of it and act as a ‘‘shock absorber.’’

The point is to make the jaw absorb and dissipate the force of a blow that otherwise would radiate upward into the skull, where it could rattle the brain."