Radiography of Caries

Question 1

caries can be classified into primary, secondary/recurrent, and residual.

describe each

Answer 1

primary caries= on a new tooth surface
recurrent/secondary= on the edge of a restoration
residual= the caries which was not fully removed when restoration placed

Question 2

caries can also be classfied based on whether it is active, inactive/ arrested.

define each.

Answer 2

active caries= ongoing de-mineralisation. e.g. rampant caries, early childhood caries, nursing/bottle caries.

arrested/ inactive caries= de-mineralisation stopped and re-mineralisation occurring therefore lesion is stable.

Question 3

caries can also be classified based on the DEPTH of disease (only enamel or dentine/pulp involvement?). in this way we define the ‘level of disease’ from D1-D4.

define each level.

Answer 3

D1= enamel caries where white/brown lesion. tooth surface still in tact.

D2= enamel caries where the tooth surface is no longer in tact, sticky fissures

D3= dentine involvement. no pulp involvement.

D4= pulp involvement.

D1+ D2 = reversible so treatment focuses on preventative measures to push towards re-mineralisation
D3+D4= require restorative treatment

Question 4

what is the GOLD STANDARD for caries diagnosis?

Answer 4

clinical inspection: dry tooth + good illumination

Question 5

what is the most common TEST for caries diagnosis?

Answer 5

radiographs, specifically BITEWING.

radiographs allow us to see lesions we wouldn’t be able to see clinically e.g. a-proximal caries and caries where there is NO cavitation but caries progressed to dentine…BUT radiographs only can detect caries when there has already been 40% de-mineralisation therefore bad at detecting early carious lesions

Question 6

what are other methods we can use for caries diagnosis?

Answer 6

FOTI- fibre optic transillumation: here we use a fine probe with a light to see inter-proximal contacts. when the light scatters= no caries but when light stops= caries.

temporary tooth seperation: allow us to see the inter-proximal areas better

laser fluorescence: fluorescence will change in different densities. caries= more fluorescent.

Question 7

what are the benefits of using bitewing radiograph for caries?

Answer 7

1. its an intra-oral radiograph that shows the POSTERIOR TEETH and ‘at risk areas’ at LOWER DOSE
2. you can see the mesial contact points for the canine –> 1st pre-molars to the most distal contact point (in adults it may take 2 radiographs to cover all contact points).
3. there is no/ very minimal enamel overlap (only ‘up to half a thickness of enamel’ overlap is accepted).
4. reproducible

Question 8

if there is caries, will the region appear radiopque or radiolucent on radiograph?

Answer 8

radiolucent (darker/bLack)

Question 9

what would occlusal caries look like on a radiograph

Answer 9

occlusal caries tends to be in pits/ fissures where food gets lodged. there will be de-calcification of enamel, and when the caries reached dentine, it will spread LATERALLY. at this point you would see a equilateral TRIANGLE shape right under the enamel.

Question 10

what would approximal caries look like on a radiograph

Answer 10

approximal caries appears on the m/d surface of tooth.

• radioluscency on these regions when only enamel is affected
• once caries spreads into dentine, it will spread LATERALLY.

to see this properly would need to have good seperation of contact points before taking a radiograph

Question 11

what would caries on the B/L surface look like on a radiograph

Answer 11

here the radiolucency is ROUND and then as the carious lesion gets bigger, the radiolucency becomes more OVOID in shape.

• this lesion does not extend onto the occlusal surface, but rather it will be localised only to the B/L surface

Question 12

what would root surface caries look like on a radiograph

Answer 12

this type of caries is due to gingival recession where the root becomes exposed. it affects the CERVICAL MARGIN of tooth on the B/L aspect

• do not get this confused with an artefact that may mimick root caries which we call the ‘cervical burnout artefact’

Question 13

what would recurrent/ secondary caries look like on a radiograph

Answer 13

you will see this on the edge of a restoration as a radiolucency there–> easier to spot with amalagam (high risk pts.)

Question 14

what are the downsides of using radiograph to diagnose caries?

Answer 14

1. harmful- use of ionising radiation
2. technique errors like faulty processing, geometry errors etc.
3. overlapping enamel= increases enamel thickness=wont see caries
4. projection= a superficial lesion can appear deeper
5. 2d representation of a 3d image= superimposition
6. lesions are larger clinically than in radiograph
7. artefacts: cervical burnout artefact and match band effect