Surveying

Question 1

Why is surveying carried out?

Answer 1

to eliminate undercut areas that would prevent the denture from being inserted or removed,
or to highlight the undercut areas that can be utilised by clasps for retention.

Question 2

What are guide planes?

Answer 2

two or more parallel tooth surfaces which determine the path of insertion (and withdrawal of an RPD)

Question 3

Define path of insertion

Answer 3

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

Question 4

Define path of withdrawal

Answer 4

Opposite to the path of insertion

Question 5

Define path of displacement

Answer 5

Any path in which the denture can be displaced

Question 6

Define the common path of displacement

Answer 6

Path taken at 90* to the occlusal plane

Question 7

What does tripoding record?

Answer 7

the common path of displacement as well as insertion and withdrawal

Question 8

What do survey lines indicate?

Answer 8

the extent of an under cut

Question 9

If an undercut isn’t utilised, what must be done?

Answer 9

below the survey line must be blocked out or avoided

Question 10

What tools does a surveyor have? (5)

Answer 10

Chuck 
Analysing Rod
Graphite Markers
3 undercut gauges (0.25, 0.5, 0.75)
Wax knife

Question 11

What are the steps for surveying

Answer 11

Position cast on surveyor table & orientate to common path of displacement

Tripod cast as common path of displacement

Check abutment teeth and associated soft tissue with analysing rod

Mark upper AND lower survey lines on the abutment teeth and associated soft tissue with graphite marker

Select undercut gauge and clearly identify undercuts which cannot be seen for mechanical retention