Jaw Relation Flashcards
(57 cards)
What is the maximal intercuspal position (MIP)?
The complete intercuspation of the opposing teeth, independent of condylar position.
What is centric occlusion?
The occlusion of opposing teeth when the mandible is in centric relation (may or may not coincide with MIP).
Define centric relation (CR).
A maxillomandibular relationship where the condyles articulate in the anterior-superior position against the posterior slopes of the articular eminences; the mandible performs a purely rotary movement.
What is the “Transverse horizontal axis”?
An imaginary line around which the mandible rotates within the sagittal plane, also called the terminal hinge axis.
What is a protrusive movement?
Mandibular movement anterior to centric relation (CR).
Define the working-side and nonworking-side during mandibular lateral translation.
The working-side is where the mandible moves in a lateral excursion; the nonworking-side moves toward the medial line in a lateral excursion.
What is a facebow?
An instrument used to record the spatial relationship of the maxillary arch to anatomical reference points, transferring this relationship to an articulator.
What are the vertical jaw relations?
The amount of separation between the maxilla and mandible under specified conditions, including Rest Vertical Dimension (RVD) and Occlusal Vertical Dimension (OVD).
Define Rest Vertical Dimension (RVD).
The postural position of the mandible when an individual is upright, with muscles in minimal contraction.
Define Occlusal Vertical Dimension (OVD).
The distance between two marked points (usually on the nose and chin) when teeth are in contact.
What is interocclusal rest distance (freeway space)?
The difference between RVD and OVD.
What are the hazards of increased vertical dimension?
Bulk sensation, loss of freeway space, muscular fatigue, TMJ pain, premature occlusion, increased ridge resorption, and elongated facial appearance.
What are the hazards of decreased vertical dimension?
Aged appearance, reduced masticatory efficiency, cheek/lip biting, angular cheilitis, prognathism, and excessive freeway space.
What are the roles of a record base and occlusal rim?
Establish vertical jaw relations, occlusal planes, and midline; determine centric relation (CR); and transfer jaw relationships to an articulator.
What is the Bennett angle setting?
An average value of 15° or calculated by the formula: L = H/8 + 12, where H is the inclination of the condylar pathway.
What is the protrusive condylar path?
The path the condyle travels when the mandible is moved forward from its initial position.
What is protrusive condylar inclination?
The angle formed by the path of the moving condyles within the sagittal plane compared with the horizontal plane.
Define mandibular lateral translation.
The translatory (medio-lateral) movement of the mandible when viewed in the frontal plane.
What is laterotrusion?
Condylar lateral movement on the working-side, also known as Bennett movement.
Define the working-side and nonworking-side condyles.
The working-side condyle is the condyle on the laterotrusive side (rotating condyle), while the nonworking-side condyle is on the translating (orbiting) side.
What is an articulator?
A mechanical instrument that represents the temporomandibular joints and jaws to which casts are attached to simulate some or all maxillomandibular relations and mandibular movements.
What is an arbitrary facebow?
A facebow designed to fit directly into the external auditory meatus (EAM), measuring an average distance from the EAM to an arbitrary hinge axis.
How is Rest Vertical Dimension (RVD) obtained?
Through methods such as swallowing, sounding M, relaxation, and electromyography.
How is Occlusal Vertical Dimension (OVD) obtained?
By subtracting 2-4 mm from the Rest Vertical Dimension (RVD).
