Guiding Planes

Question 1

What are guiding planes?

Answer 1

Vertically parallel surfaces of abutment teeth oriented so as to contribute to the direction of the path of placement and dislodgement of removable partial dentures

Question 2

What are the functions of guiding planes?

Answer 2

• Provide for one path of placement/removal
• Ensure the intended actions of the RPD components
• Eliminate/decrease gross food traps
• Increase frictional component of minor connectors
• Lowers the height of contour on proximal surfaces to allow better positioning of arms

Question 3

Do guiding planes exist naturally?

Answer 3

No - rarely

Question 4

What is one of the first steps to make a guiding plane?

Answer 4

The large undercut adjacent to the proximal surface should be reduced in size

Question 5

How can you create a guiding plane by reducing large undercuts?

Answer 5

reduction can be accomplished by altering the tilt of the cast or by selective grinding of the enamel surface

Question 6

Most often, using __________ _______, the undercut is reduced and a guiding plane is prepared.

Answer 6

selective grinding

Question 7

Where are the guiding planes located?

Answer 7

• Proximal surfaces of abutment teeth
• Parallel to long axis of teeth, if possible

Question 8

As length is increased, frictional retention is _________ and resistance to rotation is __________

Answer 8

increased
increased

Question 9

How wide should the guiding plane be?

Answer 9

• As wide as the widest portion of the occlusal rest
• One-third the bucco-lingual width of the tooth
• One-half the distance between the cusp tips

Question 10

How long should the guiding plane be?

Answer 10

• Tooth supported abutments -3.0 to 4.0 mm
• Tooth-tissue supported abutments (distal extension abutments) -1.5 to 2.0 m

Question 11

How long should the guiding plane be on a tooth supported abutments?

Answer 11

3.0-4.0 mm

Question 12

How long should the guiding plane be on a tooth-tissue supported abutments?

Answer 12

1.5-2.0 mm