Fixed Pros - Revision Lecture Flashcards
What is the definition of a dental crown
- A rigid restoration that covers parts or the whole of the external aspects of the tooth
What are dental crowns usually constructed from
- Gold
- Ceramics
- Composite resin
- Or a combo
What are some indications of a crown restoration
- To protect the remaining tooth structure
- Aesthetic demands
- Abutments for fixed/removable partial dentures
- To alter the occlusal plane
Name some types of crown restoration
- Full Gold Crown
- Partial Gold Crown
- Ceramo-Metal Crowns
- All ceramic crowns
- Composite crowns
What are some principles to keep in mind when doing tooth prep for a crown
- Preserve the tooth structures
- Retention and resistance
- Structural durability
- Marginal integrity
- Preservation of the periodontium
How close should the marginal finishing line be from the alveolar crest
not within 2mm
What is retention
Retention prevent the removal of the restoration along the path of insertion or long axis of the tooth preparation
What is resistance
Resistance prevents dislodgement of the restoration by forces directed in an apical or oblique direction and prevents any movement of the restoration under occlusal forces
AY BAWS CAN I HABE DE NOTE PLZ
Remember the taper you need after tooth prep for a crown
What is the definition of a taper in crown tooth preps
Taper is the angle between one axial wall of the preparation and the long axis of the preparation
What is the convergence angle in crown tooth preps
Convergence angle is the angle between 2 opposing axial walls of a preparation and equals the sum of the taper of 2 opposing axial walls.
When do we not need a bite registration
- When we have a bounded preparation with a stable occlusion
When do we need to have a bite registration
- When prepping the last tooth in the arch
- With multiple preparations
- With multiple anterior preparations
What is a basic description of the ICP
- This is the position where there is the most tooth to tooth contact
Why do we record the ICP
As we conform to the patient’s occlusion to ensure the restoration harmonises with the existing occlusal scheme and doesnt make occlusal interferences
What is the centric relation (RCP)
A bilateral, unstrained position of the mandible in which the condylar disc assembly is in the most superior anterior position in the glenoid fossa and the initial 20 mm of incised opening is a pure hinge axis
Name a couple materials that are used for jaw (bite?) registration
- Beauty wax
- Polyvinylsiloxane bite registration paste
Name some aspects of a good impression
- All preparation margins should be clearly visible and well defined
- No drags or air bubbles on the prep margins, axial walls, in slots, grooves or boxes
- Adequate impression of the entire arch to ensure the occlusion and shape of the other teeth are recorded
- Lack of air bubbles on occlusal surfaces of other teeth
Describe the 2 phase/single stage impression technique
- 2 materials of different viscosity are used to make 1 impression
- Light bodied material is syringed around the tooth prep to record fine detail
- Heavy bodied is loaded into the tray to take up the bulk of the space between the prep and the tray
Describe the 2 phase/2 stage impression technique
- Before tooth prep, take a heavy bodied impression of the arch
- After tooth prep, syringe light bodied material around the prepped tooth and the inside of the tooth concerned in the original impression
- Then re-seat the impression and wait for the light bodied silicone to set
What are the 3 attributes of colour
- Hue
- Value
- Chroma
Name some of the elements that affect colour
- Lighting conditions
- Value and hue contrast effect
- Metamerism
- Opalescence
- Fluorescence
- Natural tooth colour
- Surface texture
- Special characteristics
What is the hue of a colour
- This distinguishes one colour family from another and is the wavelength of light reflected by the tooth
What is the value of a colour
- This is an achromatic measure of the lightness or darkness of a colour
