Q8-Vertical Determinants of Occlusal Morphology Flashcards
What is the condylar guidance angle
it is generated by the orbiting condyle when the mandible moves laterally is larger than when the mandibular protrudes straight forward
True or False
condylar guidance is considered to be a fixed factor
True
Why is condylar guidance a fixed factor
because it is inalterable in a healthy patient; can only be altered by trauma, pathosis, and surgical procedure
What are five things that influence the height of cusps and the depths of fossa
condylar guidance anterior guidance plane of occlusion curve of spee mandibular lateral translation movement
The nearer a tooth is the to the TMJ, what will happen
the more the joint anatomy will influence its eccentric movement
The nearer a posterior tooth is the the anterior teeth, what will happen
the more the anatomy of the anterior teeth will influence its movement
The morphologic characteristics of each posterior tooth must be in harmony with what
those of opposing tooth or teeth during all eccentric mandibular movements
Mandibular movement has what components
vertical and horizontal
The greater the horizontal overlap, then what
the shorter the posterior cusps
Anterior and posterior controlling factos cause the mandibular to do what
move away from the reference (horizontal) plane at the angle degree of the articular eminence posteriorly and the anterior guidance created by the vertical and horizontal overlaps of the anterior teeth
For the maxillary premolar to disclude from the mandibular premolar during a protrusive movement, what happens
the cuspal inclines must be less than the poster and anterior controlling factors angle (45º and 60º respectively)
This is an imaginary line touching the incisal edges of the maxillary anterior teeth and the cusps of the maxillary posterior teeth
plane of occlusion
The more the plane of occlusion diverges from the angle of eminentia, what happens
the longer the cusps may be
The more parallel the plane of occlusion to the angle of eminentia, what happens
the shorter the posterior cusps
This is a bodily side shift of the mandible that occurs during lateral movements
mandibular lateral translation movement
True or False
The less medial the medial wall is from the condyle, the greater the LTM
False; the MORE medial the medial wall is, the greater the LTM
When distance exists between the medial wall and medial pole of the orbiting condyle and the TM ligament allows some movement of the rotating condyle, what occurs
LTM movement occurs
True or False
With proximity of the medial wall and tight TM ligament, no LTM
True
A what radius causes a flatter place of occlusion
longer
A what radius causes a more acute place of occlusion
shorter
Posterior teeth located distal to the radius will need what type of cusps
will need shorter cusps than those located mesial to the radius
Lateral translation movement has what three attributes
direction
amount
timing
Direction of lateral translation movement depends on what
primarily on the direction taken by the rotating condyle during bodily movement
What are the directions the rotating condyle can take
superior
anterior
inferior
posterior
The rotating condyle is capable of moving laterally within an area of what
a 60º cone during LTM;
i.e. laterally superoanterior, laterally inferoposterior
As LTM increases, the shift of the mandible distracts what
that the posterior cusps be shorter to permit LT to prevent contact between maxillary and mandibular posterior teeth
What are the two effects of timing of the LTM on cusp height
immediate LTM
progressive LTM
The more immediate the LTM, the what of the posterior cusp
the shorter the posterior cusp
The steeper the condylar guidance…
the taller the posterior cusps
The greater the vertical overlap of anterior guidance…
the taller the posterior cusps
The greater the horizontal overlap of anterior guidance…
the shorter the posterior cusps
The more parallel the plane of occlusion to the condylar guidance…
the shorter the posterior cusps
The more acute of the curve of Spee…
the shorter the most posterior cusps
The greater the LTM…
the shorter the posterior cusps
The more superior the movement of the rotating condyle…
the shorter the posterior cusps
The greater the immediate side shift
the shorter the posterior cusps
