Device for demonstrating occlusion and the effects thereof on the temporomandibular joint

A device for demonstrating occlusion which includes an upper member, portions of which simulate the maxilla and maxillary teeth located thereon and a fossa, a lower member, portions of which simulate a mandible, mandibular teeth located thereon and a condyle in a position relative to said fossa, said condyle being movable with respect to said fossa so as to permit said lower member to be moved relative to said upper member in a manner simulating normal jaw movement, such movement including rotating movement of said condyle about a hinge axis, said device including the improvement which comprises:

• said condyle being smaller than said fossa so as to be capable of being moved into and out of a centric position of said hinge axis of said condyle with respect to said fossa,
• a plurality of resilient members extending between said upper and lower members, said resilient members being connected to said upper and lower members so as to simulate muscles which normally support a mandible,
• said resilient members tending to bias said condyle generally towards said fossa into a position within said fossa which depends upon the occlusion between said maxillary and said mandibular teeth,
• said upper and lower members include hooks located thereon,
• said resilient members are rubber bands each of which extends between a hook on said upper member and a hook on said lower member,
• said hooks and said rubber bands being located so as to be visible so as to permit an explanation of the movement of said mandible to include an explanation of muscles which normally support a mandible,
• cam means associated with said condyle for controlling the position of said condyle within said fossa, said cam means being capable of being actuated so as to vary the position which said condyle assumes as the result of being biased by said resilient members,
• said cam means comprising a cam element located generally between the interior of said fossa and a part of the exterior of said condyle, said cam element being movable with respect to both said fossa and said condyle,
• said cam element is a generally wedge shaped element, said wedge shaped element being rotatable relative to said condyle around the exterior thereof,
• a transparent member overlying said condyle and said fossa,
• said condyle is represented as a disk, the periphery of which is opposite the interior of said fossa, said disk including a centrally located element,
• said transparent member including a margin which, when aligned with said centrally located element, indicates that said condyle is in said centric position,
• said mandibular teeth are located on an insert, said insert being detachable from said mandible so that different inserts simulating differently shaped mandibular teeth corresponding to different types of occlusion can be located on said mandible.