CR & CO Flashcards
What was the old definition of Centric Relation?
The most retruded relation of the mandible to the maxilla when the condyles are in the most posterior unstrained position int he glenoid fossae from which lateral movement can be made, at any given degree of jaw separation.
What is the most current definition of Centric Relation?
A condylar position that is in the most anterior and superior position within the glenoid fossa and with the articular disc properly interposed agains the articular eminence. There is no tooth contact in the centric relation position.
What is the most current definition of Centric Occlusion?
The position of the mandible when the relation ship of opposing occlusal surfaces provides for maximum planned contact and/or intercuspation. Because this is a tooth determined position, sufficient teeth must be present of the mandible to be placed in this position.
What is the Hinge Axis?
An imaginary line between the mandibular condyles around which the mandible can rotate without translator movement. (transverse hinge axis)
Define Hinge Movement.
The movement in space characterized by two divergent points moving around a central axis of rotation.
What is Vertical Dimension of Occlusion (VDO)?
The vertical dimension of the face (as determined by a vertical midline of the face between two arbitrary points above and below the mouth) when the mandible is in centric occlusion.
What is Vertical Dimension of Rest (VDR)?
The vertical dimension of the face when the mandible is in postural rest position; the person is resting their mandible while in an upright position. Teeth are not in contact.
Define Disclusion.
Non occlusion or the loss of occlusal contact between opposing teeth during tooth-guided movement or positioning of the mandible. i.e. The mandible is moved forward from centric occlusion so that the opposing incisors are in contact and the posterior teeth are no longer in contact, the posterior teeth are said to have been discluded. This term does not apply when the mandible is open and all teeth are out of occlusion.
What is Interocclusal distance?
The distance, commonly 2 to 4 mm, between the occluding surfaces of the maxillary and mandibular teeth when the mandible is in postural rest position. Usually measured at the first premolar.
AKA Freeway Space, Interocclusal Space
What is Translatory Movement?
The movement in space characterized by linear motion with no axis of rotation. Such motion can follow a straight path (rectilinear translation) or a curved path (curvilinear translation).
Define Protrusion.
Movement of the mandible in an anterior direction with an anterior translation of both condyles. Thus, when th mandible is moved forward from centric occlusion, with or without occlusal contact, it is said to be in protrusion.
Define Retrusion.
Retraction or posterior movement of the mandible from any given point.
What is Lateral Excursion?
Sideward movement of the mandible from a median occlusal position and characterized by a forward, inward and downward translation of the contralateral condyle. Thus, when the mandible is moved into a left lateral excursion, the left condyle rotates and the right condyle translates in a forward, inward, and downward direction on its articular eminence.
What is a Lucia Jig?
It is a polymer piece custom fitted to the individual that allows them to rest their mandible in Centric Relation.
AKA Anterior Deprogrammer.
