Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Prostho > 8. Lower occlusion rim > Flashcards

8. Lower occlusion rim Flashcards

1
Q

What does the lower occlusion rim determine? (3)

A
  • Determining vertical dimension.
  • Recording centric relation.
  • Mounting lower cast.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define physiologic rest position: (4)

A
  • Mandibular position, head is upright
  • Elevator and depressor muscles = equilibrium in tonic contraction (muscle tonus)
  • condyles = neutral, unstrained
  • no tooth contacts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Condyle location in physiologic rest position?

A

in front and below their position at centric relation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

physiologic rest position mandible position? (2)

A

2-4mm below MI

-AKA interocclusal rest space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define vertical dimension:

A

Distance b/w 2 selected anatomic or marked points, one on a fixed and one on a movable member (usually one on the tip of the nose and the other upon the chin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Two types of vertical dimension?

A
  • Occlusal vertical dimension.

* Rest vertical dimension.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define occlusal vertical dimension:

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define rest vertical dimension

A

Distance between two selected points measured when the mandible is in the physiologic rest position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Formula for interocclusal rest space?

A

RVD – OVD = interocclusal rest space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What reference is taken to determine vertical dimension for dentures? why?

A

physiologic rest position, because it doesn’t change so much throughout the patient’s life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Determining vertical dimension with alveolar ridges? (2)

A
  • measure distance between alveolar ridges

- get ridge to be parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Determining vertical dimension with facial proportions? (2)

A
  • Willis: distance pupil-corner of mouth = base of nose-chin

- Mc gee: Distance glabella - base of nose = base of noce to chin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Willis facial proportion?

A

distance from pupil-corner of mouth = base of nose-chin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Mc gee facial proportion?

A

Distance glabella - base of nose = base of nose to chin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What technology can we use to determine vertical dimension? (2)

A

Electromyography and kinesiography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Determining vertical dimension with lateral teleradiography?

A
  • Angle ANS-centroid-supragonion = 47o (Slavicek)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Phonetic methods to determine VD? (2)

A
  • Silverman- 2mm space for “S” sound

- Gollis - 4mm space for “M” sound (while saying emma)

18
Q

The main way to determine vertical dimension?

A

subtract 2-4mm from physiologic rest position

19
Q

Secondary method for assessing vertical dimension? (3)

A

Deglutition assessment:

  • when swallowing the mandible is at occlusal VD
  • constant height throughout life
20
Q

How do we alternatively check VD? (4)

A
  • lower occlusion rim is set at RVD (instead of OVD)
  • lower cast mounted at +2-3mm pin (interocclusal rest space)
  • Pin put at 0 again
  • inaccurate unless kinematic facebow used
21
Q

Resorption with incorrect vertical dimension? (2)

A
  • high VD = ridge resoprtion long term

- low VD = accelerated anterior ridge resorption (due to antero-rotation of mandible)

22
Q

What happens if the VD is too high? (7)

A
  • rims hit eachother when talking
  • mucosa sores
  • pain (muscles and joint)
  • bone resorption
  • long face appearance
  • full mouth sensations
  • higher ridge resoption
23
Q

What happens if the VD is too low? (3)

A
  • bone resorption (b/c antero-rotation of mandible)
  • facidity and wrinkles around mouth
  • bites own cheeks and lips b/c lack of muscle tone
24
Q

What do we use to get occlusal records? how thick? how do we fix it?

A
  • Aluwax (soft, sticky)
  • 1mm thick rectangles over the lower
  • fixed with hot wax knife
25
Q

Why do we aim for centric relation for dentures? (4)

A
  • More stability is achieved for the dentures.
  • Less ridge resorption (even load distribution).
  • Healthier position for stomatognatic system.
  • That ́s the reference that we have.
26
Q

Why is the lower occlusion rim split into 2? (2)

A
  • space for tongue - it pushes forward

- patient tends to bite with anterior teeth, moving mandible forward

27
Q

What does the thickness of the aluwax record end up becoming

A

0.5mm from 1mm intially

28
Q

How do we guide the patient into CR? (2)

A
  • press chin down with thumbs

- use rest of fingers to push angle of mandible up and forwards

29
Q

How do we heat aluwax?

A

45 degrees for 30 seconds

30
Q

The aluwax record is taken in what position? (3)

A

centric relation

  • back 45 degrees
  • head and neck hyper extended
31
Q

When mounting the lower cast what do we set the articulator to? (4)

A
  • incisal pin at 1mm
  • centric lock closed
  • PCPI 45degrees
  • articulator upside down
32
Q

Do we take three CR records and check them with a split-cast?

A

no because we would need three record bases and occlusion rims

33
Q

What type of rest vertical dimension do edentulous patients usually have?

A

Lowered rest VD

34
Q

What type of occlusal vertical dimension do edentulous patients usually have?

A

They dont have an occlusal vertical dimension

35
Q

What vertical dimensions can we restore with complete dentures and with what refences? why? (4)

A
  • Restore OVD and RVD
  • Don’t have dental refernces
  • Reference to be taken: Physiologic rest position because it doesn’t change throughout life
36
Q

What is the usual vertical rest dimension?

A

2-4mm

37
Q

What are the consequences of a low VD?

A

edentulous face

38
Q

What are the consequences of a high VD?

A

difficulty in joining the lips

39
Q

Clinical procedure to determine VD ?

A
  • Remove occlusal rims from mouth of patient
  • Mark the tip of the nose and chin
  • ask patient to open mouth for 2 mins
40
Q

What is the clinical procedure to determine VD after tiring out muscles? (4)

A
  • Ask patient to close mouth slowly relaxed
  • minimal lip pressure
  • upright position
  • head not on headrest
  • measure distance between drawn points & calculate avg
  • Ask patient to swallow a few times
  • check difference between rest VD and OVD = 2-4mm (interocclusal rest space)
41
Q

How do we alter VD when placing the occlusal rims in the patients mouth? (4)

A
  • No changes on upper rim (info would be lost)
  • Modify lower rim until it touches upper tim evenly
  • When biting at CR patient must be at estimated OVD
  • at rest there should be a space between upper and lower rims 2-4mm
42
Q

If you put too much pressure while guiding the patient into CR which muscle protectively contracts?

A

Lateral pterygoid

Prostho (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions