Lecture 7- Posselt's Envelope of Movement Flashcards
what are the 3 reference positions
-CR
-MI
-Postural position
what is pure rotational movement also referred to as and the axis
hinge movement and the terminal hinge axis
what is maximum intercuspal position
position in which the maxillary and mandibular teeth make maximum surface contact with each other. the mandible is elevated as superiorly as possible in the sagittal plane
does MIP provide any info about the TMJ
no
what is the condyle disc assembly in MIP
anterior and inferior and/or medial or lateral but usually anterior and inferior
when do you use MI
if the patient needs minimal restorations
what is postural position
the habitual postural of the mandible when the patient is resting comfortably in the upright position and the condyles are in a neutral unstrained position in the glenoid fossae
in postural position what is in equilibrium
the forces acting on the mandible
are the muscles totally relaxed in PP
no theres a degree of electromyographic activity
what is PP determined by
the muscles and the forces of gravity
does PP give info about the condyle or the teeth
neither
where are the condyles situated in PP compared to CR
anteriorly and inferiorly
what is the interocclusal space and what is it usually measured at
the wedge shaped space in between the teeth in postural position
-usually measured at 2-3 mm between incisors, 2 mm between the premolars, and 3/4-1mm between the molars
what is another term for postural position
physiological rest position
what is PP used to determine clinically
the occlusal vertical dimension in edentulous patients or in patients with severely worn dentition
what is the OVD
the distance measured between two points when the occluding members are in contact
what is the relationship between vertical dimension at rest vs OVD
vertical dimension at rest is usually 2-3 mm greater than the OVD
what are mandibular movements limited by
ligaments, the articular surfaces of the TMJ and the morphology and alignment of the teeth
what is border movements
the outer range of movements that are reproducible
where do functional movements begin and end
in the MIP
what are border and functional movements in the sagittal plane called
posselts envelope of movement
what are the movement components in posselts envelope of movement
-posterior opening border
- anterior opening border
- superior contact border
-functional movements
is the envelope the same person to person
no it differs but has the same characteristic shape
what planes are the envelope border movements
sagittal horizontal and frontal (all 3)
in posterior opening border movement what do the condyles do in opening of the mouth
forward and down the articular eminence
when maximum opening is reached in posterior opening border movement what prevents further movement
capsular ligaments
what does anterior opening border movement represent
the movement from maximum opening to maximum protrusion
what is maximum protrusion determined by in anterior opening border movement
partly by the stylomandibular ligaments
where are the condyles located in maximum protrusion in anterior opening border movement
most anterior position
where does the initial tooth contact occur in superior contact border movement
between the mesial inclines of the maxillary teeth and the distal inclines of the mandibular teeth
where does the mandible move after initial tooth contact in superior contact border movement
superio-anteriorly until maximum intercuspation occurs. also may be a lateral component to the shift
what is the average distance between Cr and MIP in 90% of the population
1.25 plus or minus 1 mm
where does the mandible move in superior contact border movement from MIP and what is it determined by
to edge to edge, determined by the lingual surfaces of the maxillary anterior teeth
where can the mandible move further horizontally
for the width of the incisal edges
what does contiuned forward movement of the mandible with the anterior teeth in contact in superior contact border movement result in
superior movement guided by the lingual surfaces of mandibular anterior teeth
continued forward movement of the mandible is guided by the posterior teeth until ___
the mandible reaches maximum protrusion
where does the chewing stroke start and return
starts at the MIP and drops downwards and forwards to the position of desired opening. returns in a straighter pathway slightly posterior
what pattern are border and functional movements in the horizontal plane
rhomboid shaped
what are the four movement components in border and functional movements in the horizontal plane
-left lateral border
-continued left lateral border with protrusion
-right lateral border
-continued right lateral border with protrusion and functional movements
what happens in left lateral border movement
contraction of the right inferior lateral pterygoid causes the right condyle to move anteriorly and medially. the left inferior lateral pterygoid relaxes
- left condyle: rotating or working condyle
-right condyle: orbiting or non-working
what happens in left lateral border movement with protrusion
from the left lateral the left inferior lateral pterygoid starts to contract while the right stays contracted and causes the left condyle to move anteriorly and to the right to maximum protrusion
where do functional movements occur
near MIP
when is the outer range of movement greater in functional movements
in the early stages of mastication
what is the pattern in border and functional movements in the frontal plane
shield shaped pattern
what are the four distinct movement components in border and functional movements in the frontal plane
- left lateral superior border
- left lateral opening border
- right lateral superior border
- right lateral opening border and functional movements
what happens in left lateral superior border movement
from MIP the mandible moves to the left
what is the path of left lateral superior border movement determined by
the morphology and interarch relationship of the teeth
what is the maximum lateral border position determined by
the ligaments of the rotating condyle
describe the path of the left lateral opening border
lateral convex path
what happens to the left lateral opening border as maximum opening approaches
ligmanets tighten and produce medial shift
what is the superior surface of the envelope determined by
tooth contacts
what are other borders in the envelope of motion determined by
the TMJ anatomy and the ligaments
