Removable Partial Denture Design - SDEO

Question 1

What is the saddle

Answer 1

The part of the removable denture which sits on the edentulous ridge and carries the replacement teeth

Question 2

What is the Kennedy Classification for this saddle and what is its name

Answer 2

Kennedy Class I

Bilateral free end saddle

Question 3

What is the Kennedy Classification for this saddle and what is its name

Answer 3

kennedy class 2

unilateral free end saddle

Question 4

What is the Kennedy Classification for this saddle and what is its name

Answer 4

Kennedy class 3

bounded saddle

Question 5

What is the Kennedy Classification for this saddle and what is its name

Answer 5

Kennedy Class 4

Anterior bounded saddle crossing the midline

Question 6

What is the classifcation for this saddle

Answer 6

Kennedy Class I, mod. 1

Question 7

What is the classification for this saddle

Answer 7

Kennedy Class II, mod. 2

Question 8

What is the classification for this saddle

Answer 8

Kennedy Class III, mod. 1

Question 9

What is support

Answer 9

the resistance of the denture to occlusally directed forces

Question 10

What should we think of when deciding which tooth to use and where each support will be placed (if using teeth)

Answer 10

the crown:root ratio

Question 11

What is class 1 Craddock Classification

Answer 11

denture is supported by remaining natural teeth

Question 12

what is class 2 craddck classification

Answer 12

vertical biting forces applied to the denture are resisted by soft tissue only

Question 13

What is class 3 craddock classification

Answer 13

tooth and mucosa borne

Question 14

how do we achieve tooth suport

Answer 14

by placing rests on the teeth which directs the forces down the long axis of the tooth

Question 15

how much can each healthy tooth support in addition to its own occlusal load

Answer 15

that of 1.5 similar teeth

Question 16

What type of dentures are rests best used

Answer 16

As part of the cast metal alloy base but can also be incorporated into the acrylic dentures however this can weaken the acrylic base

Question 17

What is essential in mucosal support

Answer 17

tilise a large area to provide greater support so to reduce load per area which is provided by the denture base

Question 18

When may we consider mucosal support

Answer 18

• Inadequate teeth available to support the number of teeth being replaced
• Teeth that are available are in poor condition
• The denture is required as a transitional or immediate denture

Question 19

When do we consider tooth and mucosal support

Answer 19

• here are inadequate teeth for tooth borne support only
• There is a free end saddle

Question 20

What are the rest types

Answer 20

• Small
• Large
• Full coverage
• Cingulum rests
• Incisal rests

Question 21

What is the issue with small rests

Answer 21

they apply a larger force per unit area and should be avoided

Question 22

how large should large rests be

Answer 22

large enough to direct forces down the long axis of the tooth

Question 23

what is a full coverage rest

Answer 23

tooth is covered with an onlay

Question 24

what does a cingulum rest require

Answer 24

may require some preparation of the enamel at the cingulum unless a prominent cingulum is already present

Question 25

what may incisal rests require

Answer 25

May require some preparation of the enamel at the incisal edge. These rests are very limited by aesthetic and are very rarely made

Question 26

Where are rests placed in a bounded saddle

Answer 26

Equal distance on either side of the saddle so the load is distributed evenly between supports

Question 27

How should rests be placed in a free end saddle

Answer 27

Should be placed on the mesial end of the abutment tooth

Otherwise abutment tooth may tilt distally - this is called distal axial torque

Question 28

What is the dimensions of a cobalt chrome rest

Answer 28

should be at least 1mm wide and a depth of 0.5mm and should cover enough tooth tissue (ideally to midline) to direct occlusal forces down the vertical axis of the tooth

Question 29

How do we ensure a rest does not interfere with occlusion

Answer 29

enamel of the tooth can be prepared if the space for a rest is required

position of a rest on the tooth can be changed to avoid preparing a rest seat

Question 30

what is the ideal placement of a rest

Answer 30

either side of a bounded saddle

mesial rest for a free ended saddle

Question 31

What is retention

Answer 31

Retention is the resitsance of the denture to vertical movements away from the tissues and can be direct or indircet

Question 32

what are the different types of direct retention

Answer 32

• ​​​mechanical
• frictional
• muscular
• physical

Question 33

What is mechanical retention

Answer 33

engages hard or soft tissue undercuts

Question 34

What is frictional retention

Answer 34

uses parellel guide planes to retain the denture base

Question 35

What is muscular retention

Answer 35

forces of the muscles keep the denture in place

Question 36

What is physical retention?

Answer 36

Forces of adhesion and cohesion to the denture bearing surface

Question 37

What does the length of the tooth have to be if it is an occlusally approaching/suprabulge clasp

Answer 37

length of the tooth has to be >15mm to accommodate the 15mm clasp arm

Question 38

What does the length of the tooth have to be for a gingivally approaching/infrabulge clasp

Answer 38

length of the tooth does not have to be > 15mm to accommodate the 15mm clasp arm