Occlusion 4 Flashcards
what is Posselt’s envelope of motion?
refers to the extreme range of motion of the mandible in the sagittal view
what is mandibular translation (horizontal)?
the translatory (medio-lateral) movement of the mandible when viewed from the frontal plane
movement to the left causes the condyle on the left to remain stationary and rotates while the right condyle and disc move forward, downward and medially within the articular fossa
what is protrusive jaw movement?
position when the jaw moves anteriorly so that both mandibular condyle and discs are forward in their glenoid fossa
what is retrusive jaw movement?
mandibular movement towards the posterior
what is anterior guidance?
when the mandible moves into protrusive, the mandibular anterior teeth glide along the lingual surfaces of the maxillary anterior teeth and disclude the posterior teeth
when does mandibular protrusion occur?
as the mandibular teeth pass their maxillary counterparts in the anterior direction and the most protruded mandibular position may range from 6 to 12 mm from centric occlusion
what is a working side?
the side toward which the mandible moves in a lateral excursion
what is nonworking side (balancing side) ?
the side if the mandible that moves toward the medial line in a lateral excursion
what is lateral excursion?
the exact pathway of the condyle on the balancing side during mediotrusion is determined by the shape of the medial wall and the superior aspect of the articular fossae, the medial pole of the balancing condyle, the congruency of the articulating disc with the articulating surfaces, the tightness of the capsule and the ligaments
what is right working movement ?
the result of rotation of the right working condyle around a vertical axis and translation of the left non working condyle down, forward and inward
what is the Bennet Angle?
the angle between the midsagittal plane and the curve of the non working condyle
what is Bennet Movement or Immediate Side Shift?
miniscule lateral shift of the whole mandible
The amount of the translatory displacement (side shift) of both condyles varies individually ……what does it depend on?
anatomical constraints such as ligaments and capsule of the working side TMJ, shape of the congruency of the balancing side condyle with the medial and superior walls of the articulating fossa and the differential activity of the masticatory muscles
what is group function?
multiple contact relations between the maxillary and mandibular teeth in lateral movements on the working side whereby simultaneous contact if several teeth acts as a group to distribute occlusal forces
what is canine guidance?
a form of mutually protected articulation in which the vertical and horizontal overlap of the canine teeth disclude the posterior teeth in the excursive movements of the mandible
