RPD

Question 1

support

Answer 1

resistance to occlusally directed load

Question 2

Kennedy class I

Answer 2

bilateral free end saddles

Question 3

Kennedy class II

Answer 3

unilateral free end saddle

Question 4

Kennedy class III

Answer 4

bounded saddle

Question 5

Kennedy class IV

Answer 5

anterior bounded saddle crossing the midline

Question 6

craddock class 1

Answer 6

tooth borne - teeth provide hard tissue resistance to occlusal loading

Question 6

craddock class 1

Answer 6

tooth borne - teeth provide hard tissue resistance to occlusal loading

Question 7

craddock class 2

Answer 7

mucosa borne - large soft tissue coverage provides resistance to occlusal loading

Question 8

craddock class 3

Answer 8

tooth and mucosa borne - reduced teeth and large edentulous spaces

Question 9

why is tooth support better

Answer 9

transmits load through PD membrane 
protects soft tissue 
comfortable 
more natural 
likely to stay in close contact with supporting structures

Question 10

disadvantages of mucosa borne

Answer 10

may damage gingival margins

more likely to displace

Question 11

types of rest

Answer 11

occlusal, cingulum, incisal

Question 12

retention

Answer 12

resistance to vertical displacement of denture - given by clasps

Question 13

best teeth for support

Answer 13

those with large roots i.e. molars then canines

Question 14

clasp thickness

Answer 14

CoCr 0.25mm, Au 0.5mm, Stainless Steel 0.75mm

Question 15

2/3s of clasp

Answer 15

should be above survey line

Question 16

terminal 1/3 of clasp

Answer 16

should be below survey line engaging the undercut

Question 17

guide planes

Answer 17

bounded saddles
2 or more parallel axial surfaces on abutment teeth
can occur naturally
more often need to be prepared
large the guide surface the more efficient it is
limit tilt and improve stability

Question 18

frictional retention

Answer 18

guide planes

Question 19

indirect retention

Answer 19

resistance to rotational displacement of denture

Question 20

examples of indirect retainers

Answer 20

major connectors, minor connectors, rests, saddle, denture base

Question 21

RPI system

Answer 21

mesial rest
proximal plate (adjacent to saddle) guide surface of 2-3mm
I-bar clasp (gingivally approaching) at greatest prominence of tooth contour

Question 22

open vs closed major connectors

Answer 22

open - greater clearance but reduced retention

closed - more contact, greater retention, guide planes but increased irritation

Question 23

plates

Answer 23

• can be thin in x section and maintain rigidity
• only recommended in mandibular arch when there is no space for a bar as they will cover gingival margin
• when less tooth support plates with confer mucosal support
• 0.5mm thickness

Question 24

bars

Answer 24

- less coverage of gingival margins - must be thick to maintain rigidity - 2mm thickness - default connector in mandibular arch

Question 25

lingual bar

Answer 25

need 8mm space: 3mm distance from gingival margin 4mm height of bar (thickness) 1mm above floor of mouth

Question 26

minor connectors

Answer 26

join components such as rests to major connector and transfer functional stresses to and from the abutment teeth

Question 27

sub lingual bar

Answer 27

4mm thickness

Question 28

path of insertion

Answer 28

path followed by denture from first contact with teeth/tissue until it fully seats

Question 29

common path of displacement

Answer 29

90 degrees to the occlusal plane (horizontal)

Question 30

why do we survey

Answer 30

to determine the path of insertion

Question 31

why do we tripod

Answer 31

records common path of displacement as well as insertion and withdrawal so it casts can be relocated to here

Question 32

how to survey

Answer 32

position cast on surveyor table orientate to common path of displacement place ruler on cast tripod use analysing rod to eyeball cast for undercuts of abutments and associated soft tissues use graphite rod to to mark upper and lower survey lines on teeth and soft tissues

Question 33

what surveyor do we use

Answer 33

ARCON - average value arcon

Question 34

survey lines

Answer 34

indicate the extent of the undercut - below the line must be used or blocked out