Orientation jaw relations are those orient the mandible to the cranium in such a way, that, when the mandible is kept in its most anterior and superior position, the mandible can rotate in sagittal plane around an imaginary transverse axis passing through or near the condyles. It demonstrates the relationship between the jaws & axis of movement. Heartwell defines hinge axis as an imaginary line around which the condyles can rotate without translation. The opening axis is an imaginary line around which the condyles may rotate during the opening & closing movements of the mandible. It serves only to orient the maxilla and to record the static starting point for functional mandibular movements. The four schools of theories regarding the Transverse Hinge axis are: Absolute location of axis, Arbitrary location of axis, Nonbelievers in the transverse axis location & Split axis rotation. The anatomic or the kinematic hinge axis face-bow transfer is the first step in recording the relationship of the maxillary arch to the condylar paths. Once the maxillary cast is oriented on the articulator, the centric relation record completes the static, or starting, relationship between the maxillae and the condyles in the temporomandibular fossae.
15 авг 2020
