Operative Dent Flashcards
What 4 things are there a strong relationship between in cavity preparation?
- the position of the caries
- the extent of the caries
- the shape of the prepared cavity
- the final restorative material
Name 4 positions of caries?
= pit & fissure
= approximal
= smooth surface
= root
What are the 6 principles of cavity design and preparation?
= identify and remove carious enamel
= remove enamel to identify the maximal extent of the lesion at the amelodentinal junction and smooth the enamel margins
= progressively remove peripheral caries in dentine - from the ADJ first, then circumferentially deeper
= only then remove deep caries over pulp
= outline form modification (cava-surface margins)- enamel finishing, occlusion, requirement of the restorative material
= internal design modification - internal line and point angles, requirement of the restorative material
What 5 things are critical in the final seal of the restoration (cavity prep)?
= smooth margins
= appropriate CSMA
= no unsupported tooth tissue
= no stress connectors
= internal anatomy that allows adaptation of material
Advantages of composite?
= aesthetics
=conservation of tooth tissue
= support for remaining tooth tissue
=adhesion/bonding
=command cure
= low thermal conductivity
= elimination of galvanism
= amalgam alternative - NHS SDR
Negatives of using amalgam…
= does not bond to enamel or dentine
= does not support the tooth
= common for pieces of tooth to breakaway
Minimum depth of amalgam bulk?
= 2mm deep
What are some examples of retention?
= undercuts
= dovetail
=key
= isthmus
What can any micro-leakage lead to?
penetration and ingress of bacteria, collection of plaque and secondary caries
Can you leave caries at the margins of the cavity?
NO
How is the hybrid layer made?
= removal of smear layer
= solubilised surface
= collagen fibril matrix
= no water content
= solvent/aqeuous primer
= hydrophobic resin
= air inhibition
What does configuration factors mean?
ratio of bonded surfaces to un-bonded surfaces ( important for composite restorations)
What is used to etch the enamel?
37% phosphoric acid - to roughen the surface
Why else are we etching the enamel and dentine?
to remove the smear layer
Smear layer?
layer of organic material which is produced whenever we use a high speed hand piece or slow speed hand piece on dentine (we want to expose out dentinal tubules)