Revision Partial Dentures Flashcards
1
Q
Why partial dentures?
A
- aesthetics
- speech
- mastication
- maxillofacial defects, ie: cleft palate
- prevention of toothwear
- prevention of unwanted tooth movement, ie: drifting
2
Q
Disadvantages of partial dentures
A
- increase in plaque accumulation
- increase risk of perio
- increase risk of caries
- damage to underlying soft tissues, ie: ulceration, denture stomatitis
- gingival stripping
- damage to remaining teeth
3
Q
Classification of support for saddle
A
Kennedy classification
4
Q
Kennedy Classification
A
Class 1 - Bilateral free end saddle
Class 2 - Unilateral free end saddle
Class 3 - Unilateral bounded saddle
Class 4 - Anterior across midline
5
Q
Modification
A
6
Q
Surveying
A
- to determine path of insertion
- to determine position and depth of undercuts, using survey lines
- some will prevent denture from seating
- some will useful for retention of denture, with/ without clasping
- to determine presence of guide planes
7
Q
Path of displacement
A
- the direction in which the prosthesis tends to be dislodged during function and is usually assumed to be perpendicular to occlusal plane
- retention will be better if path of insertion is different to path of displacement
- sometimes we tilt on the surveyor to see what options we have
8
Q
Choose denture base material
A
- may need to take in acc pt likes or dislikes
- take acc adjacent teeth and pt financial
- CoCr may not be available in clinic
9
Q
How to connect saddles together
A
- maxillary connector
- mandibular connector
10
Q
A
- buccal bar involved as there is no path of insertion in the lingual
11
Q
Kennedy Class 2 mod 1
A
- lingual bar/ lingual plate
12
Q
Clasps
A
- must have undercuts
- Chrome - 0.25mm
- Gold- 0.5mm
- SS - 0.75mm
- the longer the clasps, the more flexible
13
Q
Horizontal movement
A
- forward
- backward
- lateral
**Bracing
** higher palate has more bracing than a shallow palate
13
Q
Indirect retention
A
- ## where the denture is likely to tilt
14
Q
RPI
A
- mesial occlusal rest
- distal guiding plate
- I shaped retentive clasp, ie: I bar
- used in free end saddle situation
- normally in the mandible
15
Q
How does RPI work?
A
- saddle is loaded
- denture tends to rotate about a point close to mesial rest
- both plate and I bar move towards gingivae
- undue stress is not placed on abutment tooth
- load is spread to tissues more evenly
16
Q
What is RPI system
A
- when underload, the denture rotates towards mucosa underlying the saddle without damaging the abutment tooth
- as saddle presses into denture bearing mucosa, it rotates around mesial rest
- distal plate and I bar move down and away from tooth thus avoiding torque on abutment tooth
17
Q
When to use RPI?
A
- kennedy class 1 bilateral free end saddles
- kennedy class 2 unilateral free end saddle
- usually use in lower
18
Q
Care & maintenance of dentures
A
- remove dentures at night
- mechanical cleaning with soap and water not toothpaste
- soft brush
- immersion in chemical cleaner for 10 mins
- after chemical cleaner, store overnight in cold water
- some cleaners & certain dentures incompatible, eg: soft linings/ CoCr
- in partials, need stress the pt to clean the teeth with dentures out
19
Q
Type of Denture Cleaners
A
- all work most effectively following mechanical cleaning
- alkaline peroxides, eg: Steradent, hardens soft linings
- alkaline hypochlorites, eg: Milton/dentural, only short 10 min soak if its CoCr
- Enzymes,eg: Polident, expensive and bleaches acrylic
- Abrasive cleaners, eg: Dentu creme; abrasive- smokers