Extraoral anchorage device for use in orthopedics

Claim 1

In combination, a head harness for exerting an upward force; a pair of buccal tubes adapted to be connected to the molar teeth on the opposite sides of a human mouth and to which a vertical force is to be imparted; an extra-oral anchorage device for imparting an orthopedic force vertically to said molar teeth comprising a face bow including outer bows adapted to extend along the opposite cheeks of the user and connected to said head harness; an inner bow connected to each outer bow and having an outer free end inserted into the associated buccal tube to transmit the force applied by said harness thereto, each inner bow inserted in its associated buccal tube, means for preventing rotation of the inner bow within the buccal tube, and each inner bow being rotated or twisted about its longitudinal axis so as to impart a reverse rotation moment which substantially cancels a moment produced between each buccal tube and the resistance center of the associated tooth by said upward force transmitted thereto, whereby the orthopedic forces substantially parallel to the vertical axes of the molar teeth can be transmitted without imparting an undesired rotational moment to the teeth.