Caries Removal and Prep Flashcards
What determines cavity design?
- lack of preventative care
- restoration material
- structure of dental tissues
What may happen to someones teeth when they move from a high to low fluoride area?
Enamel may stay intact but the caries has reached the pulp.
When should you start to consider a restoration?
- when the lesion is into dentine on a radiograph
- the lesion is unaesthetic
- the lesion is into the pulp
Does dentine or enamel have a higher water content?
Dentine has a higher water content than enamel. It is more difficult to get materials to stick to a wetter surface eg. dentine.
What do you call operative procedures involving the dentine and pulp?
Dentin-pulpal complex.
What is primary, secondary and tertiary dentine?
Secondary dentin is a layer of dentin produced after the root of the tooth is completely formed. Tertiary dentin (irregular structure) is created in response to a stimulus, such as a carious attack or wear.
Primary (open tubules).
Secondary (end cut and side cut prisms).
When should you consider provisional restorations?
Gingival tissues – inflamed in presence of plaque, margins of restorations should be easy to clean.
What are principles of cavity preparation are driven by?
- caries removal
- necessary finishing required (occlusal relationships, maximising adhesion, ease of patient cleaning and properties of materials used).
When is it acceptable to remove healthy tissue?
- The material used for the restoration requires it.
- The margins of the cavity are in contact with another tooth surface.
- The margins of the cavity cross an occlusal contact.
How do you design aa cavity and prep it?
- Identify and remove caries enamel.
- Remove enamel to identify the extent of the lesion at the amelodental junction and smooth the enamel margins.
- Progressively remove peripheral carious dentine from the ADJ first then circumferentially deeper.
- Only then remove deep caries over pulp.
- Outline form modification (enamel finishing, occlusion and requirements of restorative material).
- Internal design modification (internal line and point angles and requirements of restorative material).
What is a stress concentrator?
Allows a crack to spread in a tooth- “like a scratch down a glass bottle makes it more likely to crack”.
What should the final Cavo-surface margin look like?
- smooth margin and line angles
- ensure there are no acute angles
- outline of line angles should be smooth and rounded
- no unsupported tooth tissue
- internal anatomy allows adaption of material
- check for stress concentrators
- ensure there are no remains of a previous restoration.
What is a line angle?
The angle between the wall and floor of the cavity,
Watch out for hard discoloured dentine, you don’t need to remove it if its hard as the restoration will bond.
*Photo on slide 25 “Principles of Cavity Prep” has been in an exam.
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When should you remove tertiary dentine?
When its sticky.
What is the different principles of removing caries?
1st Principle – Access Apply Dam Remove overlying enamel with a high-speed bur to gain access to carious dentine HIGH-SPEED ACCESS Follow the caries at the ADJ Do not extend into non-carious areas.
2nd Principle - Extent Caries spread at ADJ determines outline form Encloses extent of caries Clear all caries at ADJ Check Staining at ADJ Smooth enamel Cavo-surface margins Examine adjacent contact for caries Avoid trauma to adjacent tooth.
3rd Principle – remove dentinal caries
Detected as brown stain or softened tissue when using A SHARP PROBE
Sound dentine should not yield under probing
Any sticking of the probe indicates residual carious dentine which should be removed
Do not probe uncavitated carious enamel.
What is the different principles of removing caries?
1st Principle – Access Apply Dam Remove overlying enamel with a high-speed bur to gain access to carious dentine HIGH-SPEED ACCESS Follow the caries at the ADJ Do not extend into non-carious areas.
2nd Principle - Extent Caries spread at ADJ determines outline form Encloses extent of caries Clear all caries at ADJ Check Staining at ADJ Smooth enamel Cavo-surface margins Examine adjacent contact for caries Avoid trauma to adjacent tooth.
3rd Principle – remove dentinal caries
Detected as brown stain or softened tissue when using A SHARP PROBE
Sound dentine should not yield under probing
Any sticking of the probe indicates residual carious dentine which should be removed
Do not probe uncavitated carious enamel.
4th Principle - Modifications Once caries removal or removal of an existing restoration is complete: Decide what restorative material to use Modify the cavity preparation as appropriate Enamel margins CSMA Occlusion Internal anatomy Dentine quality.
CUT AN AMALGAM RESTORATION FROM THE CENTRE AND CUT TOWARDS THE EDGE OF THE CAVITY. Do not go around the edges.
NOTE: internal enamel caries is decalcified enamel.
What bur should you use to remove carious dentine?
Slow speed.
What part of the dentinal caries should be removed first and last?
First- ADJ caries.
Last- pulpal floor.
Caries here should be removed using Hand-held excavator Round bur Chemo-mechanical caries removal Caries detector dyes may be helpful.
What are the three most common restorative materials for a filling?
Amalgam, composite and resin glass modified ionomer.
What are the benefits of composite?
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? BUT – operator sensitive.
How do we prevent amalgam from fracturing?
Making sure it is atleast 2mm thick
Isthmus??
Big then small
What is the configuration factor?
Defined as the ratio of bonded to unbonded surfaces: Important for Composite restorations.
