CT scans taken with this device in place show that the tongue is more superiorly placed with a narrowing of the dorsal aspect. There is also an enlargement of the airway. This appliance uses multiple clasps to positively lock the mandible into the appliance and prevent it from retruding. There is also a larger airway cut into the acrylic in this design. The position of the mandible must be predetermined and accurately produced in a construction bite for proper appliance fabrication. Typically, the mandible must be advanced to only 75% of its maximum protrusion with the anterior/vertical separation of 4mm. This prevents excessive strain on the TMJ and facial musculature.

 IMPORTANT: Construction bite should be taken with mandible 65%-75% advanced with 4mm interincisal opening.