RPD: Components and Classification

Question 1

What are the components of a clasp?

Answer 1

Rest

Retentive arm

Reciprocating arm

Proximal plate

Question 2

What are the components of an RPD?

Answer 2

Clasp

Rest

Major connector

Minor connector

Saddle

Artificial teeth

Question 3

What does the major connector do?

Answer 3

Crosses the palate or sublingually to connect the 2 sides of the arch

Question 4

What is the minor connector?

Answer 4

Includes the grid that rests over the edentulous area and the connection to the clasp from the major connector.

Question 5

What is the saddle?

Answer 5

Holder of artificial teeth

Question 6

What is the difference between a direct and an indirect retainer on an RPD?

Answer 6

A direct retainer is a structure that attaches directly to the tooth and is responsible for retention of the RPD on the tooth structure.

An indirect retainer is located distally and prevents dislodgement of RPD at a distant location.

Question 7

What are the classes of RPDs based on the Kennedy classification system?

Answer 7

Class I = bilateral edentulous area

Class II = Unilateral distal edentulous areas

Class III = Unilateral edentulous area with teeth anterior and posterior to it.

Class IV = Anterior edentulous area crossing the midline

Modification spaces are added to refer to additional edentulous areas.

Question 8

How are the classifications determined according to applegate’s rules?

Answer 8

The classifications should be determined after all the extractions if applicable.

If the third molar is missing and is not to be replaced it is not considered in the classification.

If the third molar is present and is an abutment it is considered in the classification

If the second molar is missing and is not being replaced it is not considered in the classification.

The most posterior edentulous area always determines the classification.

Edentulous areas other than those determining the classification are referred to as modification and are designated by their number

The extent of the mod is not considered only the number of additional edentulous areas.

There is no modification in class IV

Added 2 other classes V and VI. Class V has a large edentulous space. Anterior tooth is unable to support a clasp assembly.

Class VI similar to class III but abutment teeth are much stronger with short edentulous area, this can be fixed with a fixed bridge.