Year 3 Flashcards
What is Kennedy class I saddle
Bilateral distal extension saddle
What is Kennedy class II saddle
Unilateral distal extension saddle
What is Kennedy class III saddle
Unilateral bounded saddle
What is Kennedy class IV saddle
One saddle which crosses mid-line anterior to remaining teeth
What is Craddock class I saddle
Tooth supported
What is Craddock class II saddle
Mucosal supported
What is Craddock class III saddle
Tooth and mucosal supported
What are 6 ideal features of indirect retainers
- Be rigid
- Prevent rotation of the denture
- Not interfere with the occlusion of the patient
- Be readily tolerated by the patient
- Prevent food packing
- Be placed as far as possible from the rotation point
What are 4 features influencing a clasps resistance to deformation
- Length of the clasp arm
- Diameter of the clasp arm
- Cross-sectional form of the clasp
- Type of alloy of the clasp
Where should a indirect retainer be placed
Anterior to the axis of rotation
2 types of occlusally approaching clasps
Circumferential clasps
3-arm clasps
3 types of gingival approaching clasps
T-bar
Reverse L-bar
I-bar
5 ideal features for connectors
- Cover the minimum area compatible with strength
- Be rigid enough to prevent flexure
- Prevent food packing
- Be readily tolerated by the patient
- Not cover the gingival margins
How much free space is required from the gingival margins for lower connectors
Minimum of 2 mm from gingival margins
How much free space is required from the gingival margins for upper connectors
Minimum of 5 mm from gingival margins
Name 4 upper connectors
Palatal plate
Palatal strap
Skeletal
Horseshoe
Name 5 lower connectors
Lingual bar
Sub-lingual bar
Lingual plate
Dental bar
Labial bar
5 benefits of replacing teeth
Aesthetics
Speech
Mastication
Maintenance of dental health
Physiological benefits
4 means of replacing teeth
Removable prostheses
Fixed prostheses
Implants
Orthodontics
4 benefits to oral health by replacing teeth
Maintain stability of the remaining dentition to prevent over-eruption and drifting
Reduce risk of tooth wear
Provide adequate masticatory function
Reduce risk of TMD or TMJ pathology
4 structures to record in preliminary impressions
All surfaces of all teeth
All of the palate back to junction of hard and soft palate
Bounded saddle areas: alveolar ridge, full depth of buccal, labial, lingual sulci
Distal extension saddle areas: hamular notch (upper), 2/3 retromolar pad (lower), full functional depth and width of buccal, labial, lingual sulci
How to record a preliminary impression
Select an impression tray with sufficient extension
Customise tray with compound to record palatal surface and distal extension
Add adhesive to tray and allow to dry
Add handle to tray
Load tray with aliginate
Take impression
Disinfect impression
Describe the jaw relationship to which you would restore a patient requiring a partial denture when using the conformative approach to occlusal rehabilitation
Intercuspal position (ICP) /centric occlusion
3 benefits from changing the path of insertion
- Improve aesthetics
- Improve retention
- Avoids interferences from large undercuts
Describe the jaw relationship to which you would restore a patient requiring a partial denture when using the reorganised approach to occlusal rehabilitation
Retruded contact position (RCP)
What is path of insertion
Path followed by denture from first contact with teeth until fully seated
What is path of displacement
Direction in which the denture tends to be displaced in function which is assumed to be at right angles to the occlusal plane
7 functions of guide planes
Horizontal stability
Increased retention
Reciprocation
Prevention of clasp deformation
Prevent food packing
Definitive path of insertion
Improved aesthetics
Describe 2 reasons for rest seat preparations
Provide more suitably inclined bearing surface for the occlusal rest
Provide space between the occlusal surface of the upper and lower teeth to allow a rest of adequate thickness and strength to be used
6 functions of occulsal rests
- Transmits vertical load along the long axis of the tooth
- Prevents horizontal movements
- Maintains saddle/clasps components in correct position so that they don’t sink toward the mucosa
- Deflects food impaction
- Prevents tooth over eruption
- Improves occlusion by restoring occlusal tooth contacts and avoid premature occlusion
2 materials used for master impressions
- Polyvinylsiloxane type II medium viscosity
- Alginate
4 common faults that may occur in an impression
- Tray not in correct position: not seated fully or tray offset
- Impression material already set before seat or removed too early
- Tray extension errors: under/over
- Voids /defects due to air, debris, saliva, blood, drags, insufficient
Dimensions required for mid-palatal strap
0.5mm thick x 15 mm wide