Revision RPD

Question 1

What are the reasons for treating a patient with RPD?

Answer 1

Aesthetics

Speech

Mastication

Maxillofacial defects / cleft palate- can replace soft and hard tissue defects

Prevention of tooth wear- give posterior support

Prevention of unwanted tooth movement eg: Drifting

Question 2

What are the DIS of partial dentures?

Answer 2

Increase in plaque accumulation

Increased risk of periodontal disease

Increased risk of caries

Damage to underlying soft tissues eg ulceration, denture
stomatitis

Gingival stripping – due to movement of the denture

Damage to remaining teeth

Question 3

What are index teeth and what do they help us decide?

Answer 3

Occluding pairs- help us decide whether to conform or reorganise

Question 4

What are the aims of partial denture design?

Answer 4

Replace lost teeth & tissues

Restoring function, Speech, Aesthetics

Minimise damage to adjacent teeth

Facilitate restorative treatment

Designed with periodontal health in mind

Question 5

What are the Kennedy classification?

Answer 5

Class I- bilateral FES

Class II- unilateral FES

Class III- Unilateral bounded

Class IV- anterior bounded crossing midline

Classified off most posterior saddle- additional are classified as modifications

Question 6

What is the purpose of surverying?

Answer 6

To determine path of insertion

To determine position and depth of undercuts, using survey lines
→ Some will prevent the denture from seating
→ Some will be useful for retention of the denture + / - clasping

To determine the presence of guide planes

Question 7

What is the Path of displacement?

Answer 7

Direction in which the prosthesis tends to be dislodged during function and is usually assumed to be perpendicular to the occlusal plane

-> retention is better if this is different from POI

Question 8

What plane are dentures usually surveyed in?

Answer 8

Horizontal

Question 9

In what cases would you consider surveying in a tilted position?

Answer 9

C1 and 2- consider tilting distally, could improve retention of denture (heels up- change POI/R)

C4- improved aesthetics when tilted

Question 10

What can be done if a tooth has lack of undercut?

Answer 10

Add composite to create one

Question 11

When may acrylic partials be indicated?

Answer 11

If patient only has a few teeth

If teeth of poor prognosis- easy to add to

As transitional denture

Question 12

What are the ADV/DIS of CoCr as a denture base compared to acrylic?

Answer 12

ADV:
Stronger
Less bulky
Better tolerated than acrylic

DIS:
More expensive
Difficult to add to

Question 13

What is the main issue with ring connector? (skeletal design)

Answer 13

Could irritate patient tongue

Question 14

What are guide planes ?

Answer 14

2 or more parallel surfaces which limit POI/R
-> Can be prepared in bounded saddles

Question 15

What is retention?

Answer 15

Resistance of movement away from teeth

Question 16

What are the types of clasps?

Answer 16

Premolar, anteriors, canines- gingivally approaching clasp (T/roach T or I)
-> Smaller teeth, longer arm, more flexibility

Molars- occlusal approaching
- Single arm
- Ring
-> Depends on where undercuts are

Question 17

What materials are clasps made of?

Answer 17

CoCr

Gold

SS

Question 18

What is indirect retention?

Answer 18

Prevention of displacement on rotational axis (about the clasp axis)
- A component must be opposite clasp axis to resist rotation
- Key in FES cases
- Provided by rests, connector

Question 19

What is support

Answer 19

Resistance of movement toward teeth and tissues
 Tooth support is better
 If missing teeth- some of denture bearing area will need to provide support

Question 20

What is the benefit of cutting a rest seat?

Answer 20

Ensures force is directed down the long axis

Question 21

What are onlay rests good for?

Answer 21

Increasing OVD

Question 22

What is bracing? How is it achieved?

Answer 22

Resistance to horizontal movements (forward, backward, lateral)
- Often already incorporated by design
- Done by extension into sulcus- braced against ridge

Question 23

What are the components of a RPI system?

Answer 23

• Mesial occlusal rest
• Distal guiding plate
• I bar gingivally approaching
   Can be used upper and lower

Question 24

How does an RPI system work?

Answer 24

When under load, the denture rotates towards the mucosa underlying the saddle without damaging the abutment tooth

As saddle presses into the denture bearing mucosa, it rotates around the mesial rest

Distal plate and I bar move down and away from the tooth thus avoiding torque on the abutment tooth
-> prevents undue stress and spreads load evenly

Question 25

What advice is given for care of dentures?

Answer 25

Remove Dentures at night

Mechanical cleaning with soap & water NOT toothpaste
-> Soft brush

Immersion in chemical cleaner (variable manufacturers guidelines)

After chemical cleaner – store overnight in cold water

Some cleaners & certain dentures incompatible eg soft linings/CoCr so individual advice

Remember in partials stress cleaning of natural teeth with dentures out

Question 26

What is stearadent?

Answer 26

Alkaline peroxide

-> care as it can harden soft linings

Question 27

What is Milton?

Answer 27

Alkaline hypochlorite
-> don’t use with CoCr

Question 28

What are the issues with enzyme denture cleaner?

Answer 28

Bleach acrylic

Expensive

Question 29

Clinical stages: