Surveyed Crowns

Question 1

When does one choose to fabricate a surveyed crown?

Answer 1

• to restore a badly broken down clinical crown
• to reestablish a proper occlusal plane
• to create proper rests, particularly with anterior teeth, and adequate retentive undercuts for direct retainers and guide planes when inadequate contours exist

Question 2

What is a survey crown constructed for?

Answer 2

to provide appropriate contours for the prescribed RPD abutment

Question 3

Survey crowns must be carefully planned and constructed and must include the…

Answer 3

appropriate undercuts, guiding planes, and rest seats

Question 4

What are the steps for a survey crown?

Answer 4

1. Accurate diagnostic casts must be made and carefully analyzed.
2. Definitive RPD design must be drawn.
3. Mouth preparations must be carefully planned and executed
4. Survey crown preparation
5. Laboratory process

Question 5

It is essential that re-contouring procedures be completed ________ crown (fixed restoration) procedures are begun

Answer 5

before

• including guide planes and rest seats

Question 6

What are the general considerations when prepartion a tooth for a survey crown?

Answer 6

• The occlusal or cingulum rests are constructed in metal
• Areas that engage retentive clasps can be in metal or porcelain
• Guide planes in metal

Question 7

What does the laboratory work authorization contain?

Answer 7

• Must indicate the RPD retainer selected (RPC, RPI, etc) including height of contour details
• Indicate the desired location and amount (0.1”, 0.2”, 0.3”) undercut for retentive arm
• Indicate rest details (occlusal, cingulum, etc.)
• Indicate material for rest (metal)
• Indicate other metal ceramic requirements (shade, occlusion, etc)

Question 8

The wax patterns for the surveyed crowns should be appropriately contoured by…

Answer 8

Guiding planes should be parallel to the guiding planes on the remaining teeth

Question 9

What do you need to do when waxing up the survey crown?

Answer 9

• Guiding planes are created and refined using a wax knife in the vertical arm of a dental surveyor.
• The height of contour is marked using an analyzing rod in the vertical arm of a dental surveying
• Adjustments are made with a carving instrument
• The position of the undercut is verified.
• A discoid instrument is used to finalize rest seat contours.

Question 10

Dental ceramics are ________ in compression, but _____ in tension.

Answer 10

strong
weak

Question 11

If rest is permitted to bind against the walls of a rest seat, ________ forces will result.

Answer 11

wedging

• could result in failure of ceramic restoration

Question 12

Following the addition of ceramic, crown contours are evaluated using a…

Answer 12

dental surveyor

Question 13

What do you need to do prior to the delivery appointment?

Answer 13

Prior to patient arriving, pick up crown, survey to ascertain whether lab has given you the survey line and amount of undercut you requested