RPD design

Question 1

In what order should RPD design be approached?

Answer 1

Saddles
Support
Retention
Bracing/reciprocation
Major connnector 
Minor connector

Question 2

Kennedy class I

Answer 2

Bi-lateral free-end saddle

Question 3

Kennedy class II

Answer 3

Uni-lateral free-end saddle

Question 4

Kennedy class III

Answer 4

Bounded saddle

Question 5

Kennedy class IV

Answer 5

Bounded saddle crossing midline

Question 6

Craddocks class I

Answer 6

Tooth borne

Question 7

Craddocks class II

Answer 7

mucosa borne

Question 8

Craddocks class III

Answer 8

Tooth and mucosa borne

Question 9

Benefits of tooth borne denture?

Answer 9

Allows denture to feel like normal teeth
Protects soft tissue from trauma
Transmits load via perio membrane

Question 10

how far should base be placed from gingival margin?

Answer 10

3mm

Question 11

Define Support

Answer 11

Resistance of a denture to occlusally directed loads

Question 12

What provides support?

Answer 12

Rests - occlusal, cingulum, incisal

Question 13

Other than support, what can rest seats help with?

Answer 13

Preventing over-eruption of teeth

Question 14

Define Retention

Answer 14

Resistence of a denture to vertical displacement

Question 15

What provides direct retention?

Answer 15

clasps - occlusally approaching or gingivally approaching

Question 16

Define Indirect retention

Answer 16

resistance of denture to rotational displacement

Question 17

When is indirect retention used?

Answer 17

In dentures with free end saddles

Question 18

Why is indirect retention used?

Answer 18

Because it prevents displacement of denture around fulcrum axis (where tooth and mucosa borne dentures tend to rock)

Question 19

Clasp thickness - CoCr

Answer 19

0.25mm

Question 20

Clasp thickness - Gold

Answer 20

0.5mm

Question 21

Clasp thickness - SS

Answer 21

0.75mm

Question 22

How long must a CoCr clasp be?

Answer 22

15mm

Question 23

How does should a clasp engage an undercut?

Answer 23

Terminal 1/3 engages undercut with only tip of clasp engaging to depth of 0.25mm

Question 24

What rules are there for lingual bar?

Answer 24

Reqs 8mm clearance - 3mm from ginigval margin, 4mm height of bar, 1mm from floor of mouth

Should be 2mm thick

Question 25

What kind of major connector is common choice for craddock class I?

Answer 25

Bar

Question 26

What kind of connector is the choice for craddock class II?

Answer 26

Plate

Question 27

What does an open design major connector provide?

Answer 27

< gingival coverage
> clearance
< gingival irritation

Question 28

What does a closed major connector design provide?

Answer 28

> contact = > retention

> irritation to gingival tissues

Question 29

Explain RPI

Answer 29

Stress relieving clasp system used in free-end saddle designs to prevent stress on the last abutment tooth

Question 30

What is an RPI?

Answer 30

R - Rest - mesial on occlusal surface of tooth

P - Proximal plate - adjacent to saddle. Guide surface of 2-3mm, undercut to permit movement

I - I-bar clasp - ginigvally approaching

Question 31

describe a tooth borne denture

Answer 31

denture is supported by the adjacent teeth by components such as occlusal rests, the force is transmitted to bone via teeth and periodontal ligaments

Question 32

describe a mucosa borne denture

Answer 32

denture rests on the mucoperiosteum then the force is transmitted through that tissue