Cavity Preparation Flashcards
(50 cards)
What determines cavity design?
Structure and properties of dental tissues
The diseases (caries, periodontal disease, erosion)
Properties of restorative materials
Where can the position of the caries be?
on the tooth
Pits and fissures
Approximal (posterior/anterior)
Smooth surface
Root (periodontal disease)
When should intervention occur?
When the lesion is cavitated
When the patient cannot access lesion for prevention
When is intervention considered?
(Not yet definite)
Lesion is into dentine radiographically
Lesion is causing pulpitis
Lesion is unaesthetic
What should be considered when operating on enamel?
Enamel is brittle, it should not be left under occlusal load or unsupported
Cuts should be made across enamel prisms as end cut prisms are more supported during bonding process
What are the factors that cause caries?
Bacteria
Tooth surface
Sugar (fermentable carbohydrate)
Time
What are the qualities of dentine that must be assessed?
Primary, tertiary or secondary
Intra/inter/peri tubular dentine
Diameter/ dentistry
Contents/ mineralisation
What are the principles of preparation driven by?
Caries removed
Necessary finishing required for maximising adhesion, occlusal relationships, ease of patient cleaning and properties of the materials used
When should you remove healthy tissue?
The restorative material requires it
Margins of cavity are in contact with another tooth surface
Margins of cavity cross an occlusal contact
How should enamel be removed?
Remove to identify the maximal extent of the lesion at the ADJ and smooth the enamel margins
What is the cavo-surface margins?
The junction of the cavity and the tooth
After creating the cavity, what should be ensured?
Remove enamel that will not be supported by etch technique
Smooth cavo surface margins and line angles
Ensure the outlines of the cavity are smooth and rounded (no line angle transitions)
Check for stress concentrators
What is stress concentration?
When the material is subjected to a load, a stress concentration develops around cavity
What should be checked in the final cavity design?
Ensure no traces of previous restorative material remain
Smooth eternal enamel sharp line or point angles
Create appropriate cavo-surface margin angle
Remove internal dentinal sharp line or point angles
Check for stress concentrators
Why should the cavity be cleaned?
To ensure it is free from debris generated during preparation
How should you access caries? (1st principle)
Apply dam
Remove over-lying enamel with high-speed burr
Follow caries at ADJ
Do not extend into non-carious areas
How should you extent the cavity? (2nd principle)
Spread of caries at ADJ determine outline form
Clear all caries at ADJ
Check staining at ADJ
Smooth enamel cavo-surface margins
Examine adjacent contact tooth for caries and avoid trauma to adjacent tooth
What % of direct plastic restorations are replacement restorations? (Replacing amalgam)
80%
How is a previous restoration removed? (What burr)
High speed burr
What should you never do when removing a previous restoration?
Never remove a restoration by cutting around the edges - thus increasing the size of the cavity excessively.
Start from the centre of the restoration and cut towards the edge of the cavity.
How should the previous restoration be removed?
Cut restorations into pieces with the high speed burr
Try to chip out chunks where possible
How should you remove dentinal caries? (3rd principle)
Stain should be left if hard to probe
Stain musts be removed from the ADJ
Residual carious dentine must be removed first from the ADJ and last from the pulpal floor
Caries should be removed using a
-hand-held excavator
-round bur
-chemo-mechanical methods
What are the qualities of carious dentine?
Detected as a 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
What can be helpful in identifying carious dentine?
Caries detector dyes
