Brainscape's Knowledge GenomeTM

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


See full index

Dentistry BDS3 > DENTURES2 > Flashcards

DENTURES2 Flashcards

1
Q

What is an Impression?

A

Negative replica of tissues which is converted into positive model cast in stone or plaster

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

What are the main impression materials used in denture making?

A

Alginate

Impression compound

Silicone

Polyether

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

What other impression materials may be used to aid denture construction?

A

ZOE- not elastic

Agar (reversible hydrocolloid)- duplication of casts

Impression plaster

Impression waxes

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

What are the advantages/disadvantages of alginate?

A

ADV- cheap, easy to use, elastic, accurate

DIS- messy, poor dimensional stability (but ok for dentures)

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

What are the features of impression compound?

A

Non-elastic (only used for free end saddles)

Poor surface detail

Expensive

Messy

Only used for primary impressions

Can burn patient

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

What are silicones and polyethers used for?

A

Master impressions- more accurate than alginate

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

What are the features of silicones

A

Dimensionally stable

Hydrophobic

Variety of consistencies

Can be messy to use

Very accurate

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

What are the features of polyethers?

A

Dimensionally stable

Hydrophilic (better)

No variety of consistencies (always medium body)

Can be messy to use

Very accurate

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

What is the clinical relevance of impressions?

A

Allows link and communication between dentist and technician

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

What tray should be used in complete dentures?

A

Edentulous tray- shallower

Should engage over alveolar ridge and engage full depth of sulcus

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

How do you choose the right tray?

A

Look and estimate correct size

Try it in:
Too small if flanges hit ridge

Too large- stretches mouth

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

When do you sue elastic impression materials like alginate?

A

If there are undercuts

Use non-elastic if no undercuts

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

Where should you stand when taking an impression?

A

Upper- behind

Lower- in front

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

What are the steps in taking an alginate impression?

A

Rotate the tray in

Position the tray before seating it

Manipulate the tissues (pull lip over etc)

Keep holding the tray until it is set

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

What are the steps in preparing impression compound?

A

Immerse in water bath at 55-60°C for 4-5 mins- ensures complete softening

Place gauze/paper towel at bottom of bath to prevent sticking

Handle with vaseline on gloves

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

What happened if you knead compound?

A

Water is incorporated and acts as plastciser

17
Q

What happens if you leave impression compound in bath too long?

A

Becomes difficult to handle- components leach out and affect properties

18
Q

How do you take an impression using compound?

A

Rotate the tray into patients mouth

Use firm pressure to seat tray

Tissuemoulding

Remove the impression

19
Q

What should be checked when inspecting impressions?

A

Is denture bearing area covered

Peripheral seal (should be difficult to remove)

Surface detail- accurate

Can a satisfactory cast be produced

20
Q

How are impression decontaminated in GDS?

A

Rinse under tap to remove gross debris or saliva

PERFORM- 10mins

21
Q

What should be detailed in the stage and date sections of the prescription card?

A

Stage- what you want done

Date- when is work required

22
Q

Following a primary impression what should you ask the lab to provide?

A

Light cured special trays with handles (IO or EO) with spacing

Casts

23
Q

How much spacing is required for different materials?

A

Alginate- 3mm

Silicone or polyether:
Upper- 2mm
Lower- 0.5-1mm

24
Q

How do you correct an under/over-extended special tray

A

Over- trim extension

Under- border moulding

25
Q

What is border moulding? (may not be needed for alginate)

A

Addition of material (greenstick/silicone or wax) to the outside of the periphery of the trays to fill the functional sulcus

26
Q

Where are stops prescribed to be positioned to create space in the upper tray?

A

In canine and post dam regions (whole posterior border)

27
Q

What are the purposes of occlusal stops?

A

Allows accurate correction of posterior borders of tray

Preform space for impression material

Help stabilise special tray

28
Q

How thick should the occlusal stops be for different impression materials?

A

Alginate- 3mm

Light body silicone- 1mm

29
Q

Where are occlusal stops prescribed to create space in the lower tray?

A

Retromolar pad

Ridge in canine areas

30
Q

What do we look for upon inspection of master impression?

A

Coverage of denture bearing area

Good functional sulcus

Good surface detail

Suitability for master casting

31
Q

What does the replication of the functional sulcus help the technician with?

A

Getting right flange width

32
Q

What do we want the lab to produce for the next visit?

A

Master casts

Wax record blocks

33
Q

When making replica dentures why is it helpful to modify them temporarily with green stick?

A

Checks assessment is correct

Makes later stages easier

34
Q

What are the steps in modifying a denture with green stick

A

Heat slowly- wait until it goes matt

Place large piece

Shape approximately

Mould in mouth (finger pressure and swallowing)

35
Q

When temporarily modifying a denture where should green stick not be placed?

A

On fitting surface

Modification should be done on polished surface (often in mylohoid space)

36
Q

What are the objectives when taking replica dentures?

A

Replica should be dimensionally accurate, have a solid base for recording working impression and have easily modifiable occlusal and polished surfaces

37
Q

What should you ask the lab to produce following replica impression?

A

Replica blocks in wax or shellac

Ready for second impressions and occlusion

Dentistry BDS3 (7 decks)

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