Removable partial dentures Flashcards
What are the 6 steps to designing partial dentures?
- Identify teeth to be replaced
- Support
- Retention
- Major connectors
- Indirect retention
- Reciprocation
What are the 4 classes of the Kennedy classification?
Class 1 - bilateral free end saddle
Class 2 - unilateral free end saddle
Class 3 - bounded saddle
Class 4 - bounded saddle crossing midline
What is the definition of support?
Resistance of a denture to occlusal directed forces
What is the definition of rest seats For support?
Provide support for dentures from vertical opposing forces
How should a rest seat be prepared?
Remain in enamel 1mm minimum 0.5mm thickness
Should not be placed in occlusal centric stop
What are the primary support for maxilla and mandible?
Maxilla:
- palate and palatine raphe
Mandible:
- pear shaped pad, buccal shelf and sulcus
What are the secondary support for maxilla and mandible?
Maxilla:
- maxillary tuberosity, residual ridge, rugae, incisive papilla and torus
Mandible:
- buccal shelf (alveolar ridge)
What is the definition of retention?
Resistance of a denture to vertical dislodging forces
Direct retention - resistance to vertical displacement
Indirect retention - resistance to rotational displacement
What materials and size is required for retention clasps?
CoCr 0.25mm
Gold 0.5mm
Stainless steel 0.75mm
What are the components of RPI system?
Mesial occlusal rest
Proximal guide plate adjacent to saddle 2-3mm undercut to permit movement
I-bar gingival approaching clasp
Using maxillary connector how far should they be from gingival margin?
5mm
Using mandibular connectors how far should they be from gingival margin?
3mm
Lingual bar how much space does it required?
8mm
3mm from gingival margin
4mm for bar
1mm from functional level of FOM
What extra function does a lingual plate provide?
Used for stabilisation of anterior periodontal compromised teeth
A denture patient has the following teeth 45, 44, 43, 33, 34, 35, 36 and 37. What is the Kennedy classification?
Class 2 modification 1
Gypsum products are prohibited on landfills because they produce which gas?
Hydrogen sulphide
What is the setting reaction of acrylic?
Activation
Initiation
Propagation
Termination
What are the components of CoCr alloy and their properties?
Cobalt 35-65% - rigidity Chromium 20-35% - corrosion resistance Nickel 0-30% - ductility Mo 0-7% - hardens and strengthens Carbon - embrittles
A patient with new F/F returns complaining of difficulty pronouncing F and V sounded. What is the issue?
Incorrect buccal lingual position of teeth especially anterior teeth
What occurs when PMMA construction is incorrectly cured?
Base becomes porous
Increased residual monomer
Develops whitening of acrylic
The reference plane indicator for denar articulator identifies position 43mm from the incisal edge of 12 or cusp tip of 13. What is the practical importance of this?
To ensure the mounted casts are equi distant between upper and lower arms of the articulator.
What denture components function is to determine path of insertion?
Parallel guide planes
What is the average mesio distal width of a maxillary lateral incisors?
6.5mm