Lecture 7- Posselt's Envelope of Movement

Question 1

what are the 3 reference positions

Answer 1

-CR
-MI
-Postural position

Question 2

what is pure rotational movement also referred to as and the axis

Answer 2

hinge movement and the terminal hinge axis

Question 3

what is maximum intercuspal position

Answer 3

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

Question 4

does MIP provide any info about the TMJ

Answer 4

no

Question 5

what is the condyle disc assembly in MIP

Answer 5

anterior and inferior and/or medial or lateral but usually anterior and inferior

Question 6

when do you use MI

Answer 6

if the patient needs minimal restorations

Question 7

what is postural position

Answer 7

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

Question 8

in postural position what is in equilibrium

Answer 8

the forces acting on the mandible

Question 9

are the muscles totally relaxed in PP

Answer 9

no theres a degree of electromyographic activity

Question 10

what is PP determined by

Answer 10

the muscles and the forces of gravity

Question 11

does PP give info about the condyle or the teeth

Answer 11

neither

Question 12

where are the condyles situated in PP compared to CR

Answer 12

anteriorly and inferiorly

Question 13

what is the interocclusal space and what is it usually measured at

Answer 13

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

Question 14

what is another term for postural position

Answer 14

physiological rest position

Question 15

what is PP used to determine clinically

Answer 15

the occlusal vertical dimension in edentulous patients or in patients with severely worn dentition

Question 16

what is the OVD

Answer 16

the distance measured between two points when the occluding members are in contact

Question 17

what is the relationship between vertical dimension at rest vs OVD

Answer 17

vertical dimension at rest is usually 2-3 mm greater than the OVD

Question 18

what are mandibular movements limited by

Answer 18

ligaments, the articular surfaces of the TMJ and the morphology and alignment of the teeth

Question 19

what is border movements

Answer 19

the outer range of movements that are reproducible

Question 20

where do functional movements begin and end

Answer 20

in the MIP

Question 21

what are border and functional movements in the sagittal plane called

Answer 21

posselts envelope of movement

Question 22

what are the movement components in posselts envelope of movement

Answer 22

-posterior opening border
- anterior opening border
- superior contact border
-functional movements

Question 23

is the envelope the same person to person

Answer 23

no it differs but has the same characteristic shape

Question 24

what planes are the envelope border movements

Answer 24

sagittal horizontal and frontal (all 3)

Question 25

in posterior opening border movement what do the condyles do in opening of the mouth

Answer 25

forward and down the articular eminence

Question 26

when maximum opening is reached in posterior opening border movement what prevents further movement

Answer 26

capsular ligaments

Question 27

what does anterior opening border movement represent

Answer 27

the movement from maximum opening to maximum protrusion

Question 28

what is maximum protrusion determined by in anterior opening border movement

Answer 28

partly by the stylomandibular ligaments

Question 29

where are the condyles located in maximum protrusion in anterior opening border movement

Answer 29

most anterior position

Question 30

where does the initial tooth contact occur in superior contact border movement

Answer 30

between the mesial inclines of the maxillary teeth and the distal inclines of the mandibular teeth

Question 31

where does the mandible move after initial tooth contact in superior contact border movement

Answer 31

superio-anteriorly until maximum intercuspation occurs. also may be a lateral component to the shift

Question 32

what is the average distance between Cr and MIP in 90% of the population

Answer 32

1.25 plus or minus 1 mm

Question 33

where does the mandible move in superior contact border movement from MIP and what is it determined by

Answer 33

to edge to edge, determined by the lingual surfaces of the maxillary anterior teeth

Question 34

where can the mandible move further horizontally

Answer 34

for the width of the incisal edges

Question 35

what does contiuned forward movement of the mandible with the anterior teeth in contact in superior contact border movement result in

Answer 35

superior movement guided by the lingual surfaces of mandibular anterior teeth

Question 36

continued forward movement of the mandible is guided by the posterior teeth until ___

Answer 36

the mandible reaches maximum protrusion

Question 37

where does the chewing stroke start and return

Answer 37

starts at the MIP and drops downwards and forwards to the position of desired opening. returns in a straighter pathway slightly posterior

Question 38

what pattern are border and functional movements in the horizontal plane

Answer 38

rhomboid shaped

Question 39

what are the four movement components in border and functional movements in the horizontal plane

Answer 39

-left lateral border
-continued left lateral border with protrusion
-right lateral border
-continued right lateral border with protrusion and functional movements

Question 40

what happens in left lateral border movement

Answer 40

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

Question 41

what happens in left lateral border movement with protrusion

Answer 41

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

Question 42

where do functional movements occur

Answer 42

near MIP

Question 43

when is the outer range of movement greater in functional movements

Answer 43

in the early stages of mastication

Question 44

what is the pattern in border and functional movements in the frontal plane

Answer 44

shield shaped pattern

Question 45

what are the four distinct movement components in border and functional movements in the frontal plane

Answer 45

• left lateral superior border
• left lateral opening border
• right lateral superior border
• right lateral opening border and functional movements

Question 46

what happens in left lateral superior border movement

Answer 46

from MIP the mandible moves to the left

Question 47

what is the path of left lateral superior border movement determined by

Answer 47

the morphology and interarch relationship of the teeth

Question 48

what is the maximum lateral border position determined by

Answer 48

the ligaments of the rotating condyle

Question 49

describe the path of the left lateral opening border

Answer 49

lateral convex path

Question 50

what happens to the left lateral opening border as maximum opening approaches

Answer 50

ligmanets tighten and produce medial shift

Question 51

what is the superior surface of the envelope determined by

Answer 51

tooth contacts

Question 52

what are other borders in the envelope of motion determined by

Answer 52

the TMJ anatomy and the ligaments