Athletic mouthpiece capable of sensing linear and rotational forces and protective headgear for use with the same

A mouthpiece assembly for use in detecting impact forces on the neck and head of a user is disclosed. The mouthpiece assembly includes sensors which determine linear and rotational impact forces on the user. The mouthpiece assembly includes a mouth guard having a channel sized to receive the upper teeth therein. A raised dome portion extends from the mouth guard and is adapted to be positioned adjacent the roof of the mouth. The sensors are located in the raised dome portion and the mouth guard or in other locations of the mouthpiece if mouthpiece sensors are required. An indicator is provided to provide a visual and/or audible indication when the magnitude of an impact exceeds a threshold value.