10. Lab Processes Setting Teeth for RPDs

Question 1

Aims when setting artificial teeth for partial dentures (4)

Answer 1

Complement existing teeth
Restoring arch
Restoring aesthetics
Restoring function

Question 2

What will be improved if the aims when setting artificial teeth for partial dentures can be achieved (2)

Answer 2

Greatly improve patient self-confidence

Protect their prosthetic/denture privacy

Question 3

Difference between setting teeth for a cobalt chromium (metal) base or PMMA (acrylic base)

Answer 3

No difference

Question 4

What should setting teeth achieve (2)

Answer 4

Fill in the gaps

Maintain the patients’ prosthetic privacy

Question 5

Setting teeth for aesthetics and functions involve (5)

Answer 5

Choosing artificial teeth
Matching the existing natural teeth
Customising artificial teeth
Setting teeth to the existing dentition
Trial dentures (assessment)

Question 6

Considerations when choosing artificial teeth

Answer 6

Teeth should be chosen to match the mould, shape and shade of the natural dentition under natural lighting

Question 7

Types of artificial teeth materials (2)

Answer 7

Acrylic

Porcelain

Question 8

Features of plastic/acrylic teeth materials (7)

Answer 8

Chemical bond with denture base
Natural appearance and feel - silent in function
Tough
Soft - low abrasion resistance
Easily trimmed and polished/customised
Cold flow underpressure
Insoluble in mouth fluids - some dimensional changes

Question 9

Features of porcelain teeth materials (7)

Answer 9

Mechanical attachment with the denture base (silane coupling agent - provided by a metal retention pin)
Natural appearance - possible noise in function
Brittle
Friable - grinding removes surface glaze
Inert in mouth fluids - no dimensional change
High heat distortion - no permanent deformation under forces of mastication

Question 10

Tooth moulds match (4)

Answer 10

Shape of tooth (square, ovoid, tapered)
Length of anterior teeth
Height of central incisor
Width of central incisor
(Moulds can be customised to make them look more natural)

Question 11

Definition of ridge lap (3)

Answer 11

Part of an artificial tooth (found in acrylic teeth) that is adjacent to the residual ridge and can lead to the appearance of a natural tooth
The ridge lap is slightly softer which improves bonding
If an alveolar ridge is present, the ridge lap may have to be trimmed, affecting bond strength

Question 12

Methods to provide symmetry of appearance (2)

Answer 12

Set teeth to the long axis of the corresponding tooth

Check the contact points