Gaining Access and Removal of Carious Tissue Flashcards
What are dental caries and name some characteristics of them
- reversible but progressive disease
- Initiated by bacteria in a plaque biofilm
- Fermenting Carbohydrates
- Producing Acid
- Demineralsing Inorganic Component
- Proteolytic destruction of organic component
Name some isolation techniques that can be used for dental procedures
- Rubber dam
- Cotton wool rolls
- Dry guards
- Aspiration
What probe/explorer should be used when examining carious regions
Round/bell-ended not sharp
What are the 3 main sites that caries develop at
- Pits and fissures/cingulum
- Approximal below contact area between teeth
- Smooth surface
What scores can be given for caries severity
0-4
Describe the features and histology of a 0 ICDAS score caries
No/slight change in enamel translucency after prolonged (>5s) air drying
Histology - No enamel demineralisation or narrow zone opacity
Describe the features and histology of a 1 ICDAS score caries
Opacity/discolouration of enamel hardly visible on wet tooth, visible after air drying
Histology - enamel demineralisation outer 50%
Describe the features and histology of a 2 ICDAS score caries
Opacity/discolouration visible without air drying. No clinical cavitation visible
Histology - enamel demineralisation inner 50% through to outer 1/3 dentine
Describe the features and histology of a 3 ICDAS score caries
Localised breakdown in opaque/discoloured enamel +/- greyish discolouration/shadowing or underlying dentine
Histology - Demineralisation of middle to inner 1/3 dentine
Describe the features and histology of a 4 ICDAS score caries
Gross cavitation in opaque/discoloured enamel exposing underlying dentine
Histology - Demineralisation of inner 1/3 dentine towards pulp
What do different ICDAS approximate caries scores appear as on Bitewing Radiographs
0 - Sound on bitewing
1 - Radiolucency confined to enamel
2 - Radiolucency in enamel up to EDJ
3 - Radiolucency in enamel and outer half of dentine
4 - Radiolucency in enamel and reaching inner half of dentine
Describe the different classes of Black’s classification of caries
1 - pits and fissures 2 - Posterior inter/aproximal caries 3 - Anterior inter/aproximal caries 4 - Incisal edge 5 - Cervical lesion/smooth surface caries
What kinds of caries are bitewings good and bad for
- Good for inter proximal caries
- Less good for occlusal
What kinds of caries can dental panoramic homographs good for
- Can show occlusal caries well
- Not routine for caries detection
What kind of caries can periodical radiographs be used for
- Assessment of apical status
- Not routine for caries detection
IF there is a large caries lesion or there is suspect that the vitality of the tooth has been affected what special investigations are there
Sensibility testing - not vitality testing - tests nerve supply - usually related to blood supply and therefore vitality
- Thermal testing - endofrost
- Electronic pulp tester - 0-10 - strong nerve supply, higher values = higher nerve loss
- Test cavity but this is last resort as it will heart patient
What preventative management strategies are there for caries
- OH
- Fluoride
- Diet advice
What operative management strategies are there for caries
- Gain access
- Identify sound and carious tissue
- Excavate caries
- Modfiy cavity for restorative material
- Restore
What are the aims for enamel preparation when treating caries
- Gain access to full extent of lesion
- Remove demineralised/weakened and unsupported enamel
- Create sound peripheral margin to seal with restorative material
What equipment do we use in enamel preparation
- Air-rotor - spin very fast and is dangerous
- Diamond or Tungsten Carbide burs
- (Hand chisels not used anymore)
What do we need to know about the caries before we begin dentine removal
- Anatomical extent - lateral extent from EDL and overlying pulp
- Histological depth - caries infected vs caries affected vs sound dentine
What is caries infected dentine
Bacteria has progressed into dentine and has been demineralised and there’s been proteolytic dissolution of the collagen substructure - must be removed
What is caries affected dentine
Where dentin has begun to be demineralised but collagen fibres are still largely there so you may be able to remineralise the dentine
What do we do when removing caries in sequence
- Access through enamel
- Identify EDJ
- Identify caries-infected/affected/sound dentine
- Clear EDJ - Clear caries infected dentine
- Clear from periphery to the centre
- Decision when to leave caries affected dentine - as long as good seal, carbs can’t reach bacteria
What equipment might we use for dentine removal
- Slow handpiece (<5000rpm)
- steel rose head burs
- hand excavators
Why do you want to use the largest bur that you can to get into the cavity for dentine removal
- Small bur = uneven cavity surface
Describe the differences between caries-infected, affected and sound dentine visually
Infected - Dark brown
Affected - Paler brown/translucent
Sound - Yellow/white
Describe the differences between caries-infected, affected and sound dentine upon feeling it
Infected - soft/sticky
Affected - Sticky/flaky/scratchy
Sound - Scratchy
Describe the differences between caries-infected, affected and sound dentine using dyes (not used a lot)
Fusayama dyes - can penetrate deeper into affected dentine leading to overpreparation
What is retention
The property of a cavity to resist displacement of the restoration in the direction of its placement
What is resistance
The property of the cavity to resist displacement of the restoration in any other direction
What other methods of caries removal are there
- Air abrasion
- Cavitron - vibrating tips - tends to be used to remove calculus now
- Carisolv - solution put into tooth, left in there, softens carious dentine but doesn’t affect sound dentine and then scoop out
- Lasers
