RPD design and surveying

Question 1

Kennedy Class I

Answer 1

bilateral free end saddle

Question 2

Kennedy Class II

Answer 2

unilateral free end saddle

Question 3

Kennedy Class III

Answer 3

bounded saddle (that does not cross the midline)

Question 4

Kennedy Class IV

Answer 4

bounded saddle that crosses midline

Question 5

Craddock Class 1

Answer 5

tooth borne

Question 6

Craddock Class 2

Answer 6

mucosa borne

Question 7

Craddock Class 3

Answer 7

tooth AND mucosa borne

Question 8

support

Answer 8

resistance to occlusally directed load

Question 9

retention

Answer 9

resistance to vertical displacement

Question 10

benefits of occlusal rests

Answer 10

• prevent movement of RPD towards mucosa
• distribute occlusal load
• prevent over eruption of unopposed teeth

Question 11

why is the default position for free end saddle rests the opposite side of the tooth

Answer 11

to reduce axial torque on the abutment

Question 12

indirect retention

Answer 12

resistance to rotational displacement

Question 13

reciprocation

Answer 13

prevents clasp arm moving clasp tooth

Question 14

bracing

Answer 14

resistance to lateral movement

Question 15

where should plates be in relation to gingival margins

Answer 15

either completely away or completely covering

those that end at gingival margins known as ‘ gum strippers’

Question 16

RPI

Answer 16

stress relieving clasp system 
common in mandibular arch 
R - mesial rest 
P - proximal plate 
I - I bar clasp

Question 17

what is the purpose of the guide plate on an RPI

Answer 17

ensures forces directed down vertical plane

Question 18

how much sulcus height is needed for gingivally approaching clasp s

Answer 18

7mm

Question 19

CoCr minimum clasp length

Answer 19

15mm

Question 20

CoCr undercut depth

Answer 20

0.25mm

Question 21

stainless steel undercut depth

Answer 21

0.75mm

Question 22

gold undercut depth

Answer 22

0.5mm

Question 23

how much clearance is needed between gingival margins and floor of mouth to place a lingual bar

Answer 23

8mm

Question 24

what teeth are best for providing support

Answer 24

canines and molars

Question 25

how long a saddle can teeth support before it becomes partially mucosa borne

Answer 25

healthy teeth can carry 1.5 similar teeth

so bounded saddle could be 3 teeth wide and still be fully tooth borne

Question 26

what is the primary objective of surveying

Answer 26

to find a suitable path of insertion

Question 27

what is a dental surveyor

Answer 27

a paralleling instrument used to identify and mark the maximum contours of tooth hard and soft tissues in order to fabricate a removable denture

Question 28

common path of displacement

Answer 28

90 degrees to the occlusal plane - horizontal

Question 29

why do we alter the path of insertion

Answer 29

to eliminate spaces which in turn provides better aesthetics and better retention

Question 30

what does the chiselled edge of the graphite marker allow for

Answer 30

allows it to go interproximal

Question 31

what must be done with undercuts when creating a rpd

Answer 31

they must be either used or blocked out