Impressions

Question 1

How can ridge resorption be classified?

Answer 1

Cawood and Howell classification- 1-6.

Question 2

Why do we render patients edentulous?

Answer 2

Caries
Advanced perio disease
Toothwear
Occlusal collapse
Failing dentitions
Appearance

Question 3

What information is required for a complete denture history?

Answer 3

How long have you had your current dentures for?
How many sets of dentures have you had?
When did you get your first set of dentures?
What do you like about them?
What do you not like about them?
Can you eat with them in?
Are they loose?
Speech
Any discomfort

Question 4

What aspects of the dental history are important?

Answer 4

Why were teeth lost?
When were teeth lost?
Any retained roots, pain or swelling?
Anxiety surrounding dental environment

Question 5

WHta aspects of the medical history will make denture provision difficult?

Answer 5

Xerostomia
Sjogren’s
Radiotherapy
Parkinson’s
Stroke
Dementia
Bisphosphonates- risk of MRONJ
Diabetes- higher risk of infection

Question 6

Where do you get primary support in the upper arch?

Answer 6

Mostly from the palate and tuberosity.

Secondary support from the alveolar ridge.

Question 7

Where do you get primary support in the lower arch?

Answer 7

Buccal shelf and retro molar pad.

Secondary support from the alveolar ridge and genial tubercles.

Question 8

What limiting areas exist in the upper arch?

Answer 8

Buccal sulcus, buccal frenum and labial frenum.

Question 9

What limiting areas exist in the lower arch?

Answer 9

Retromolar pad- denture should extend 2/3 along the retromolar pad.

Buccal sulcus, labial and buccal frenum.

Question 10

What relief areas are there in the lower arch?

Answer 10

Mylohyoid ridge.

Question 11

Where should the post dam be?

Answer 11

Anterior to the vibrating line.

Question 12

What should be examined at the initial appointment?

Answer 12

Full E/O examination (usual stuff)
I/O- teeth left, caries, perio, BPE, sensibility tests if required.
- Look at the soft tissues, any signs of denture stomatitis, denture hyperplasia, soft tissue lesions.

Face height
OVD, RVD and freeway space
Occlusal planes, incisal planes, dentofacial midline.
Naso-labial angle
Overextension or under extension
Lip support
Retention- push down on the anterior teeth and see if the posteriors drop
Stability- push down unilaterally on one side of the denture and see if the other side pops up
Adaptation
Check for a balanced occlusion- in RCP
Guidance

Question 13

Where should the upper and lower dentures extend to?

Answer 13

Uppers- to the vibrating line
Lowers- 2/3 along the retromolar pad

Question 14

What is the purpose of primary impressions?

Answer 14

To allow for the fabrication of special trays and treatment planning.

Question 15

What type of impression tray are you going to use for your primary impressions?

Answer 15

Edentate perforated tray.

Question 16

What materials can you use to extend your stock tray?

Answer 16

Green stick
Putty
Red composition wax
Soft red wax

Question 17

Where and why might you want to reduce the extension of the tray?

Answer 17

In post dam area if the patient has a bad gag reflex.

Frenal attachments and muscle attachments.

Lingual tori.

Remove with an acrylic bur.

Question 18

What are the limitations of a stock tray?

Answer 18

Might not be an exact fit of the patient

Often under or over extended

Limited sizes

Question 19

Under what circumstances might you use composition wax instead of alginate?

Answer 19

Retching patients- sets quicker and is more rigid so doesn’t compress with the denture bearing area.

Question 20

What is border moulding?

Answer 20

Shaping of the border areas of an impression tray by functional or manual manipulation of the tissues adjacent to the borders to duplicate the contour and size of the vestibule.

Ask the patient to stick their tongue out and move it from side to side.
You can also massage the border areas of the tray.

Question 21

What material are master impression trays made out of?

Answer 21

VLC resin PMMA (acrylic)

Question 22

Why might you want to ask for a close fitting tray?

Answer 22

If the ridge is very resorbed

Question 23

What are the advantages of special trays?

Answer 23

Uniform thickness of material

Accurate peripheral extension

Records denture bearing area more accurately.

Question 24

What modifications can you ask the lab to make for the special tray?

Answer 24

Finger rests for lower special trays
- usually when the ridges are very resorbed.

Intra-oral handle
- usually when the ridges are very resorbed.

Tight fitting tray

Question 25

Describe the technique for taking impressions with someone that has a flabby ridge.

Answer 25

You want to avoid compression of the fibrous tissue during the impression taking procedure.

Perforate the special tray over the flabby ridge
Take an alginate impression of the area.
Then remove the alginate from the flyby ridge area and add some light bodied silicone to that area and reinsert the impression.
- less mucocompressive.