Removable Partial Dentures

Question 1

Path of placement/path of insertion

Answer 1

The specific direction in which the prosthesis is placed on the residual alveolar ridge, abutment teeth, dental implant abutment(s) or attachments.

Question 2

Retention

Answer 2

The quality inherent in the dental prosthesis acting to resist the forces of dislodgement along the path of placement.

Question 3

Guide planes

Answer 3

Limit the path of insertion = better retention

Question 4

Support

Answer 4

The foundation area on which a prosthesis rests; with respect to dental prostheses, the resistance to forces directed toward the basal tissue or underlying structures.

Question 5

Rest seats

Answer 5

Provide support for the prosthesis

Question 6

Saddle

Answer 6

The part of the denture which rests on the foundation tissue and to which teeth are attached.

Question 7

Classification for partial dentures that we use

Answer 7

Kennedy (1925)

Applegate (1960)

Question 8

Class I kennedy classification

Answer 8

Bilateral free end saddles

Rest seats on mesial side of most mesial teeth

Question 9

Class II kennedy classification

Answer 9

Unilateral free end saddle

Question 10

Class III kennedy classification

Answer 10

Tooth bounded saddle

Question 11

Class IV kennedy classification

Answer 11

Free end saddle anteriorly

Question 12

Class V Applegate

Answer 12

Tooth bounded edentulous saddle where the anterior abutment is weak e.g. lateral incisor abutment that is incapable of providing support for conventional RPD and the edentulous space is long.

Question 13

Class VI Applegate

Answer 13

Tooth-bounded edentulous area but restoration can be a fixed partial space as the edentulous space is short and abutments are capable of providing support for the denture

Question 14

Design steps for RPD

Answer 14

1. Saddle
2. Support: rest seats
3. Retention: clasps, guide planes
4. Indirect retention: rest seat
5. Minor connectors
6. Major connectors
7. Simplification - so much metal can we simplify the design

Question 15

Craddock denture types

Answer 15

Tooth-borne
Mucosa-borne
Mucosa- and tooth-borne

Question 16

What is indirect retention?

Answer 16

Resistance to rotation about clasp axis by acting on the opposite side to the displacing force.
(Prevents denture from rocking where there is a free end saddle)

Question 17

RPI System

Answer 17

Rest
Proximal plate
I bar
Whenever there is a fre end saddle, covering more than 180 degrees of the tooth.

Question 18

When would you consider the altered cast technique?

Answer 18

Long saddles

Question 19

Types of rest seats

Answer 19

Occlusal, cingulum, incisal (not placed due to aesthetics)

Question 20

How do you prepare a rest seat?

Answer 20

Marginal ridge is lowered to allow sufficient thickness without creating an occlusal interference - to 1-1.5mm

Question 21

Teeth where rest seats will be provided should be…

Answer 21

Periodontally sound, have enough tooth tissue and good endodontic status

Question 22

How to find out where to place clasps?

Answer 22

Use a surveyor to draw lines over abutment teeth. These lies will show you the bulbosity of your abutment teeth = height of contour and gingival to this is the undercut. Clasps will engage at the undercut.

Question 23

Different types of clasps

Answer 23

Occlusally approaching

Gingival approaching: I bar, T bar, J bar and Y bar

Question 24

When should RPA (Akers) system be used?

Answer 24

Can’t accommodate a gingival approaching clasp e.g. not enough gingival sulcus for I bar to engage the tooth or massive bony tuberosity
Rest seat, proximal plate + akers clasp

Question 25

Aesthetic clasps properties

Answer 25

Made from thermoplastic resin, no metal show, great resistance to fracture, lose brightness over time, difficult to adjust and repair

Question 26

Major connectors should be

Answer 26

Rigid, have smooth and rounded line angles, conform to anatomic structures, not interfere with moveable tissues, not allow food entrapment, not cover more tissue than necessary, not use marginal gingiva for support and not impinge on soft and hard tissue.

Question 27

Types of major connectors for maxilla

Answer 27

• Anterior-posterior palatal strap (ring)
• Palatal strap
• Palatal plate
• Horseshoe (if pt gags, bony tuberosity)

Question 28

Types of major connectors for the mandible

Answer 28

• Lingual bar (need minimum 7mm space
• Sublingual bar
• Dental bar
• Lingual plate (most commonly used)
• Labial bar (if pts’ teeth are too lingually placed, rarely used e.g. cancer pts)

Question 29

Minor connector

Answer 29

Anything that connects bits of the denture together.