Composites Flashcards
Name the type of Composite used for dentine and why
Chemical cure
- Increased porosities
- Colour degradation due to amide linkages
- Does not polish as well
How many cusp tips lower 5
3
How many cusp tips upper 5
2
How many cusp tips lower 6
5
How many cusps tips lower 7
4
Where is marginal ridge in relation to central disecting groove in most teeth
At 45 degree angle
Describe upper 6 Anatomy
2 buccal cusps 1/2 each
2 Palatal cusps mesial 2/3 and distal 1/3
Name two teeth where the marginal ridge is not at 45 degrees to the central disecting groove
Lower 5
Lower 6
Define fossae
Where opposing cusps meet
Describe Anatomy lower 5
3 cusp tips
Buccal 1 cusp marginal ridge at 90 degrees to central disectional groove
Palatal 2 cusps marginal ridge at 45 degrees to central disectional groove
Define hue
Colour of the tooth
Define chroma
Saturation or intensity of the hue
Define value
Brightness of color light or dark
What is c factor
Ratio of bonded to unbonded surfaces
What are the different types of composite layering
Horizontal layering
Vertical layering
Oblique layering
Which way does a composite shrink
Away from the walls
What is the c factor of a class 2 cavity
Ratio 4:2 c factor =2
Bonded = buccal lingual distal base
Unbounded mesial occlusal
Class 1 cavity what is the c factor
Ratio 5:1 c factor 5
Bonds ;base, buccal mesial distal lingual
Undonded occlusal
Why should flowable line cavity (4)
To wet the floor of the cavity
Reduce air voids
Reduce post op sensitivity
Allow some elasticity to the restoration during curing and function
How thick should the dentine layer of composite be
1mm below the top of the cavity
What is the advantage of ramped /stepped curing
The Composite cures slower less risk of shrinkage stress
Out of horizontal vertical and oblique layering what type provides the most amount of shrinkage
Horizontal
Out of horizontal vertical and oblique layering what type provides the most likely to cause post op sensitivity
Vertical layering
What are the advantages of layering composite
Stress reduction
Better polymerisation
Better aesthetics
Better Anatomy
What does glycerin do on composites
Get rid of the oxygen inhibition layer
When and why is a composite resealed
When : after shaping
Why: to seal microleakage that has occurred during shaping
Young teeth have high
A. Value
B. Hue
C. Chroma
Value
When assessing shade where should be assessed
Hydrated tooth
Mid 1/3
What are the differences between adult front tooth and young teeth
Young teeth : whiter, dentine lobes are fully covered with enamel
Adult teeth : thinner enamel thickness, darker dentine , more of an ivory tint
What are the advantages of bevelling
Improves etch pattern as prisms are etched at the long axis
Stronger bond and seal due to inter and intraprismatic bond
What degree is a composite bevel
60 degrees
What is the Disadvnatges of bevelling composites
Thin edge of material left
Increased risk of chipping and staining
Increased risk of white line at the margin
Harder to finish tooth coloured Restoration.
What are the qualities of resealing after shaping a composite
Resin which goes into the micro fractures eg thermal, fortifill
