2/21: Posselt's Envelope of Movement

Question 1

What is centric relation?

Answer 1

Position of the mandible in which the condyles are in the most superior and anterior position in the articular fossae, resting against the posterior slopes of the articular eminences

Question 2

What is the condyle determined position?

Answer 2

Centric relation

Question 3

When the mandible is in centric relation the condyles can rotate around a horizontal axis up to an opening of _________ mm measured at the central incisors

Answer 3

20-25mm

Question 4

What is pure rotational movement referred to? And the axis is referred to as?

Answer 4

Hinge movement; terminal hinge axis

Question 5

What is maximal intercuspal position?

Answer 5

Maxillary and mandibular teeth make maximum surface contact with eachother
- the mandible is elevated as superiorly as possible in the sagittal plane

Question 6

What is a tooth determined position?

Answer 6

Maximal intercuspal position or maximum intercuspation

Question 7

What position doesn’t provide any information about the TMJ?

Answer 7

MI

Question 8

In most people, ______ does not coincide with ______

Answer 8

MIP; CR

Question 9

Describe the condyle-disc assembly in MIP?

Answer 9

Condyle assembly is anterior and inferior and/or medial or lateral or a combination of the above compared to their position in CR

Question 10

What position are restorations made in with minimal restoration (e.g., amalgam or composite resin restorations, single crowns, etc)?

Answer 10

Maximum intercuspation

Question 11

What is postural pisition?

Answer 11

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 12

Where is there an equilibrium in postural position?

Answer 12

Equilibrium between the forces acting on the mandible

Question 13

How are muscles in postural position?

Answer 13

Not totally relaxed; there is a degree of electromyographic activity

Question 14

What is postural position determined by?

Answer 14

The muscles and the forces of gravity

Question 15

What does postural position NOT give us information on?

Answer 15

Condyles or the teeth

Question 16

How are the teeth positioned in postural position?

Answer 16

Teeth are apart and there is a wedge space between the teeth

Question 17

What is the wedge shaped space called?

Answer 17

Interocclusal space and is usually 2-3mm between the incisors, 2mm between the premolars, and 3/4-1mm between the molars

Question 18

What is postural position aka physiological rest position clincially used to determine?

Answer 18

The occlusal vertical dimension (OVD) in edentulous patients or in patients with severly warn dentition

Question 19

What is the occlusal vertical dimension?

Answer 19

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

Question 20

Compare the vertical dimension at rest and the occlusal vertical dimension

Answer 20

The vertical dimension at rest (in the physiological rest position) is usually 2-3mm greater than the occlusal vertical dimension

Question 21

What are the types of movement?

Answer 21

Rotation
Translation
Combination of both

Question 22

What are mandibular movements limited by?

Answer 22

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

Question 23

What is the outer range of movements called?

Answer 23

Border movements

Question 24

When do functional movements occur?

Answer 24

During functional activity of the mandible

Question 25

What are functional movements confined within?

Answer 25

Border movements

Question 26

When do functional movements begin and end?

Answer 26

In the maximum intercuspation position

Question 27

What are movement components of posselt's envelope of movement?

Answer 27

Posterior opening border Anterior opening border Superior contact border Functional movements

Question 28

What is envelope of motion a combination of?

Answer 28

Border movements in all 3 planes: A. Sagittal B. Horizontal C. Frontal

Question 29

What happens during opening of the mouth in posterior opening border movement?

Answer 29

The condyles will move forward and down the articular eminence

Question 30

When is maximum opening reached?

Answer 30

When capsular ligaments prevent further movement

Question 31

What does anterior opening border movement represent?

Answer 31

The movement from maximum opening to maximum protrusion

Question 32

What ligaments is maximum protrusion determined by?

Answer 32

Stylomandibular ligaments

Question 33

Where are the condyles in anterior opening border movement?

Answer 33

Most anterior position

Question 34

Where does initial tooth contact occur in superior contact border movement?

Answer 34

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

Question 35

Where does the mandible move in superior contact border movement?

Answer 35

From MIP to edge to edge

Question 36

What is the mandible movement determined by in superior contact border movement?

Answer 36

The lingual surfaces of the maxillary anterior teeth

Question 37

What does continued forward movement of the mandible, with the anterior teeth in contact result in?

Answer 37

Superior movement guided by the lingual surfaces of mandibular anterior teeth

Question 38

What are continued forward movement of the mandible guided by?

Answer 38

The posterior teeth until the mandible reaches maximum protrusion

Question 39

Where does the chewing stroke start at? then where does it go?

Answer 39

MIP and drops downwards and forwards to the position of desired opening

Question 40

What shape pattern is the border and functional movements in the horizontal plane?

Answer 40

Rhomboid shaped pattern

Question 41

What four movement components make up horizontal plane?

Answer 41

1. Left lateral border 2. Continued left lateral border with protrusion 3. Right lateral border 4. Continued right lateral border with protrusion and functional movements

Question 42

What does contraction of the right inferior lateral pterygoid cause?

Answer 42

The right condyle to move anteriorly and medially The left interior lateral pterygoid relaxes Left condyle: Rotating or working condyle Right condyle: Orbiting or non-working or balancing

Question 43

What happens in the left lateral border with protrusion?

Answer 43

From the left lateral the left inferior lateral pterygoid starts to contract (the right stays contracted) and causes the left condyle to move anteriorly and to the right to maximum protrusion

Question 44

Where do functional movements occur?

Answer 44

Near MIP

Question 45

When are the outer range of movements greater?

Answer 45

In the early stages of mastication

Question 46

When are the outer range of movements smaller?

Answer 46

In the late stages of mastication

Question 47

What pattern of the border and functional movements of the frontal plane follow?

Answer 47

Shielf-shaped pattern

Question 48

What are the four distinct movement components of the frontal plane?

Answer 48

1. Left lateral superior border 2. Left lateral opening border 3. Right lateral superior border 4. Right lateral opening border

Question 49

What is the maximum lateral border position determined by?

Answer 49

The ligaments of the rotating condyle

Question 50

What is the superior surface of the envelope determined by?

Answer 50

The tooth contacts

Question 51

What are borers primarily determined by?

Answer 51

TMJ anatomy and the ligaments

Question 52

1. What is the name of this envelope 2. Define the position of all the numbers and letters 3. What does it represent

Answer 52

1. Posselt's envelope 2. 1. CI 2. MI 3. Protrusion 5-3. Maximum opening R. Postural position