Guiding Planes

Question 1

What are Guiding Planes?

Answer 1

Guiding Planes
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

Guiding Planes…

Answer 2

rarely exist naturally
so,

Guiding Planes MUST be created

Guiding Planes Ensure the intended actions of the RPD components

Question 3

What are the functions of Guiding Planes?

Answer 3

• 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 4

How is a Guiding Plane prepared?

Answer 4

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

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

The goal is to make the path of insertion as flat or straight as possible.

Question 5

Describe the location of Guiding Planes:

Answer 5

• Proximal surfaces of abutment teeth
• Parallel to long axis of teeth, if possible
• As length is increased, frictional retention is increased and resistance
to rotation is increased

Question 6

As length is increased, what happens to friction?

Answer 6

As length is increased, frictional retention is

increased and resistance to rotation is increased

Question 7

Describe the width of guiding planes:

Answer 7

• 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 8

Describe the length of guiding planes

Answer 8

• Tooth supported abutments -3.0 to 4.0 mm
(Kennedy 3 and 4)

• Tooth-tissue supported abutments (distal
extension abutments) -1.5 to 2.0 mm (Kennedy 1 and 2)