Revision RPD Flashcards
What are the reasons for treating a patient with RPD?
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
What are the DIS of partial dentures?
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
What are index teeth and what do they help us decide?
Occluding pairs- help us decide whether to conform or reorganise
What are the aims of partial denture design?
Replace lost teeth & tissues
Restoring function, Speech, Aesthetics
Minimise damage to adjacent teeth
Facilitate restorative treatment
Designed with periodontal health in mind
What are the Kennedy classification?
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
What is the purpose of surverying?
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
What is the Path of displacement?
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
What plane are dentures usually surveyed in?
Horizontal
In what cases would you consider surveying in a tilted position?
C1 and 2- consider tilting distally, could improve retention of denture (heels up- change POI/R)
C4- improved aesthetics when tilted
What can be done if a tooth has lack of undercut?
Add composite to create one
When may acrylic partials be indicated?
If patient only has a few teeth
If teeth of poor prognosis- easy to add to
As transitional denture
What are the ADV/DIS of CoCr as a denture base compared to acrylic?
ADV:
Stronger
Less bulky
Better tolerated than acrylic
DIS:
More expensive
Difficult to add to
What is the main issue with ring connector? (skeletal design)
Could irritate patient tongue
What are guide planes ?
2 or more parallel surfaces which limit POI/R
-> Can be prepared in bounded saddles
What is retention?
Resistance of movement away from teeth
What are the types of clasps?
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
What materials are clasps made of?
CoCr
Gold
SS
What is indirect retention?
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
What is support
Resistance of movement toward teeth and tissues
Tooth support is better
If missing teeth- some of denture bearing area will need to provide support
What is the benefit of cutting a rest seat?
Ensures force is directed down the long axis
What are onlay rests good for?
Increasing OVD
What is bracing? How is it achieved?
Resistance to horizontal movements (forward, backward, lateral)
- Often already incorporated by design
- Done by extension into sulcus- braced against ridge
What are the components of a RPI system?
- Mesial occlusal rest
- Distal guiding plate
- I bar gingivally approaching
Can be used upper and lower
How does an RPI system work?
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
What advice is given for care of dentures?
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
What is stearadent?
Alkaline peroxide
-> care as it can harden soft linings
What is Milton?
Alkaline hypochlorite
-> don’t use with CoCr
What are the issues with enzyme denture cleaner?
Bleach acrylic
Expensive
Clinical stages:
