Brainscape's Knowledge GenomeTM

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


See full index

3rd yr- CSB- Partial dentures > Academic background for impressions for dentures > Flashcards

Academic background for impressions for dentures Flashcards

1
Q

What do we want to record when taking an impression for a denture

A
  1. We want the full extend t of the denture bearing area

2. Want the functional depth of the sulcus

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

List some key anatomical denture bearing areas for a lower denture

A
  1. Buccal sulcus
  2. Buccal shelf
  3. Pear shaped pad
  4. Retromolar pad
  5. Mylohyoid ridge
  6. Lingual sulcus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name the muscles that change the shape of the buccal sulcus in the lower arch

A
  1. Buccinator

2. incisive muscles

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

Name the muscles that change the shape of the buccal sulcus in the upper arch

A

Buccinator

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

Where is the buccal shelf found

A

Between the alveolar ridge and insertion of the buccinator into the external oblique ridge

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

Why is the buccal shelf important when making dentures

A

It is an area where the denture can extend onto

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

At the back of the mouth where does the denture bearing area extend up to?

A

The retormolar pad

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

What is the pad at the back of the lower arch split into?

A
  1. The retromolar pad

2. The pear shaped pad

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

Where is the pear shaped pad found?

A

It is the anterior to the retromolar pad

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

Where is the retromolar shaped pad found?

A

It is the posterior 2/3rds of the pad

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

Which pad do we usually cover with our denture?

A

The pear shaped pad

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

Where is the functional depth of the sulcus on the posterior lingual side of the lower arch

A

Extends beyond the Mylohyoid ridge into the posterior retro Mylohyoid area

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

List some key anatomical denture bearing areas for an upper denture

A
  1. Buccal sulcus
  2. Vibrating line
  3. Palate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where do we extend an upper denture up to?

A
  1. Extend as far as the buccinator posteriorly
  2. Palatal coverage unto vibrating line
  3. Upto to the palatine fovea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What should impressions record in terms of the frenum

A

Impressions should record the space created when the frenum moved to all possible positions

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

What is the frenum

A

It has no muscle fibres excepts at the mid line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What the natural portion of the frenum

A

Natural portion is perpendicular to the ridge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What can restrict the width of the upper posterior buccal sulci?

A

The coronoid process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What problems can arise if we don’t consider the coronoid process

A

We can make a bulky denture that will restrict patients masticatory function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How can we take the coronoid process into consideration when taking an impression?

A

We can ask the patient to move their jaw from side to Side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

List some physical properties of the oral mucosa that can affect impression taking

A

1, Depth of mucosa over the denture bearing area

  1. Visco elastic nature of mucosa
  2. Depth and width of the sulcus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens to the elasticity of the mucosa as you get older

A

It becomes less elastic and if you press the mucosa it doesn’t bounce back into its original position straight away

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What can happen if we make a denture that is in essence too tight

A

It can restrict blood flow to that area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What happens to the depth and width of the sulcus

A

It moves when you take an impression

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

At what depth do we need to record the sulus

A

Functional depth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is the functional depth determined by

A

Determined by anatomy and movement

So muscle movement and muscle insertion define the depth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Buccally the functional depth is usually the ___________ depth

A

Minimum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the functional depth limited by lingually?

A

Limited by the tongues movement to normal physiological positions (so not the minimum depth)

29
Q

What is the width of the sulcus created by

A

Created by the action of the muscles and frenum on the impression material

30
Q

Functional width is a _______ or ________ width

A

Tolerated

Accepted

31
Q

Why is the functional width usually a tolerated width

A

As there is no natural resting width to a sulcus until something is inserted into it

32
Q

List soem impression philosophies

A
  1. Muco-displasive,
  2. Muco-static
  3. Differential Pressure
  4. Functional
33
Q

What is the muco-displasive impression philosophy

A

It advocates a high viscosity material giving a high pressure technique which aimed to compress (displace) the mucosa into a loaded portion

34
Q

What are the benefits of the muco-displasive impression philosophy

A

Blains to give good retention

35
Q

What is a disadvantage of the muco-displasive impression philosophy

A

Likely to increase resorption of alveolar bone

36
Q

Is the muco-displasive impression philosophy used much today

A

No it is mostly for historical interest

37
Q

What has replaced the muco-displasive impression philosophy

A

The altered cast technique

38
Q

Name the only time we might use the muco-displasive impression philosophy

A

In a lower free end saddle

39
Q

What is the Muco-static principle

A

It is an attempt to record the mucosa in its rest position

40
Q

What are the advantages of the Muco-static principle

A

Comfortable for patient

Preserves underlying bone

41
Q

What is a disadvantage for the Muco-static principle

A
  1. Lack of peripheral seal
  2. Lack of retention
  3. Any impression moves the mucosa so mucosa isn’t really static
42
Q

What is the differential pressure impression philosophy

A

A broad term that covers all impression which aim to be high pressure in some areas and low pressure in relatively mucostatic in others

43
Q

What is the functional impression philosophy

A

It is a closed mouth technique in which an impression is taken beneath functioning dentures
It utilises a slow setting material which is placed beneath the denture
and the patient goes away for a period (2 hours upto 2 days) and
moulds the impression in function

44
Q

How is the functional impression technique carried out

A

It utilises a slow setting material which is placed beneath the denture
and the patient goes away for a period (2 hours upto 2 days) and
moulds the impression in function.

45
Q

What are the advantages of the functional impression technique

A

The denture bearing area is recorded in function that is said to give a better resultant contour when the denture is loaded

46
Q

What are the disadvantages of the functional impression technique

A

The patient need pre existing dentures
Theres hygiene problems when taking the denture
You cannot select the areas to load

47
Q

When is it useful to take a functional impression

A

Useful fro re lines of existing dentures

48
Q

How do we take dentures in Leeds

A

We use an acrylic, spaced special tray, unperforated from the lab which may be perforated chair side
We use silicone for chrome dentures and alginate for partial acrylic dentures

49
Q

Which technique have we adopted in Leeds

A

The relatively mucostatic impressions technique

50
Q

What material do we use to take an impression for a chrome denture

A

Silicone

51
Q

What material do we use to take an impression for a partial acrylic denture

A

Alginate

52
Q

What Qualities do we look at when picking our impression material

A
  1. Viscosity
  2. Elasticity
  3. Dimensional stability
  4. Hydrophilic
  5. Handling properties
53
Q

Do we want a high or low viscosity material for taking impressions?

A

Ideally low for low pressure relatively mucostatic impressions
BUT high enough viscosity not to run out of the tray

54
Q

How elastic do we want our impressions material to be?

A

Enough to emerge easily from undercut without tearing

55
Q

Why is dimensional stability an important property for impression materials

A

As the impression must stay the same shape over time until it is cast

56
Q

Do we want a hydrophilic or hydrophobic material when taking impressions

A

hydrophilic

57
Q

Why does out impression material need to be hydrophilic

A

TO give close adaptation and surface detail

58
Q

What handling poverties do we need to look at when deciding which impression material to use

A
  1. Mixing time
  2. Working time
  3. Setting time
59
Q

Name the ideal impression material

A

One hasn’t been invented yet

60
Q

How many impressions do we usually take before creating a denture

A

2
Primary impression
Secondary impression

61
Q

What does the primary impression aim to show

A

Gives us a bold outline of the denture bearing area and which teeth are present

62
Q

What does the secondary impress allow us to do

A

Produce a customised tray (special tray)

63
Q

Describe the type of tray you would use for a low pressure relatively mucostatic impressions

A
  1. Rigid material for the tray- acrylic
  2. Spaced- for a low pressure
  3. Unperforated
  4. Stub handles
  5. Finger rests
  6. tray adapted or trimmed 2mm short of the functional depth of sulci given on the primary cast
64
Q

Why do we use a spaced tray for partial dentures

A

As teeth are present so a spaced tray will allow the impression material to come out of the undercut without tearing

65
Q

Why do we need stub handles on our impression tray for partial dentures

A

so we don’t interfere with muscle trimming

66
Q

Why do we need finger rests on our impression tray for partial dentures

A

to make it easy to hold the impression intra orally

67
Q

What do perforation do

A

They reduce pressure BUT they also create uneven loading

68
Q

Which factor has the largest effect on impression taking

A

operator technique

3rd yr- CSB- Partial dentures (5 decks)

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