Revision Partial Dentures

Question 1

Why partial dentures?

Answer 1

• aesthetics
• speech
• mastication
• maxillofacial defects, ie: cleft palate
• prevention of toothwear
• prevention of unwanted tooth movement, ie: drifting

Question 2

Disadvantages of partial dentures

Answer 2

• 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

Question 3

Classification of support for saddle

Answer 3

Kennedy classification

Question 4

Kennedy Classification

Answer 4

Class 1 - Bilateral free end saddle
Class 2 - Unilateral free end saddle
Class 3 - Unilateral bounded saddle
Class 4 - Anterior across midline

Question 5

Modification

Question 6

Surveying

Answer 6

• 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

Question 7

Path of displacement

Answer 7

• 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

Question 8

Choose denture base material

Answer 8

• may need to take in acc pt likes or dislikes
• take acc adjacent teeth and pt financial
• CoCr may not be available in clinic

Question 9

How to connect saddles together

Answer 9

• maxillary connector
• mandibular connector

Question 10

Answer 10

• buccal bar involved as there is no path of insertion in the lingual

Question 11

Kennedy Class 2 mod 1

Answer 11

• lingual bar/ lingual plate

Question 12

Clasps

Answer 12

• must have undercuts
• Chrome - 0.25mm
• Gold- 0.5mm
• SS - 0.75mm
• the longer the clasps, the more flexible

Question 13

Horizontal movement

Answer 13

• forward
• backward
• lateral

**Bracing

** higher palate has more bracing than a shallow palate

Question 13

Indirect retention

Answer 13

• ## where the denture is likely to tilt

Question 14

RPI

Answer 14

• mesial occlusal rest
• distal guiding plate
• I shaped retentive clasp, ie: I bar
• used in free end saddle situation
• normally in the mandible

Question 15

How does RPI work?

Answer 15

• 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

Question 16

What is RPI system

Answer 16

• 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

Question 17

When to use RPI?

Answer 17

• kennedy class 1 bilateral free end saddles
• kennedy class 2 unilateral free end saddle
• usually use in lower

Question 18

Care & maintenance of dentures

Answer 18

• 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

Question 19

Type of Denture Cleaners

Answer 19

• all work most effectively following mechanical cleaning

1. alkaline peroxides, eg: Steradent, hardens soft linings
2. alkaline hypochlorites, eg: Milton/dentural, only short 10 min soak if its CoCr
3. Enzymes,eg: Polident, expensive and bleaches acrylic
4. Abrasive cleaners, eg: Dentu creme; abrasive- smokers