Caries

Question 1

What do caries look like?

Answer 1

• Caries absorbs less radiation than sound tooth substance
• It’ll appear as a radiolucency as more radiation passes through the demineralised area
• In radiographs, you can detect; early/ advanced interproximal caries, advanced occlusal caries, the extent of the caries, and caries in restorations

Question 2

What are the radiographic codes in rating caries?

Answer 2

1: Outer 1/2 enamel
2: Way into enamel
3: Just into dentine
4: Quite into dentine
5: Near the pulp

Question 3

List the issues with occlusal caries and radiographs?

What is the first sign of occlusal caries?

Answer 3

• Radiographs are far less useful in detecting occlusal caries than interproximal caries
• Thick cuspal enamel is superimposed over the lesion, so it makes it hard to detect
• First radiographic sign - thin radiolucent line at the DEJ, with little or no enamel changes
• As caries progresses, this diffuse radiolucency spreads pulpally and possibly mesiodistally

Question 4

List the issues with buccal/ palatal/ lingual caries and radiographs

Answer 4

• Generally close to the cervical margins
• Lesion may be superimposed on pulp or dentine
• Whether the caries is buccal or lingual / palatal cannot be accurately determined

Question 5

Describe root caries

Answer 5

• Involve cementum and dentine, no enamel involved
• Located below the cervical region of tooth crown
• Accompanied by bone loss and gingival recession
• Appears just below the cemento-enamel junction in contact area

Question 6

What is cervical burn-out?

What is the appearance of dentinal sclerosis?

Answer 6

• Cervical burn-out translucency: evident on the neck of the tooth, and it happens because at the cervical region, there is dentine only, thus less tissue for X-ray to penetrate. Hence the uniform radiolucency at the cervical area of the tooth
• It is seen uniformly on all teeth in the radiograph

Dentine sclerosis:
• Reaction of the odontoblasts to trauma
• Increase in dentine mass as a protective mechanism

Question 7

What are the limitations of radiographic diagnosis? (5)

Answer 7

• Caries are only detectable radiographically when a sufficient amount of calcium & phosphorus has been removed from the tooth (estimated 50% mineral loss)
• Carious lesions are always larger clinically than they appear radiographically
• Early lesions are not apparent radiographically
• Technique variations in film position and x-ray beam angulation affect the image of the lesion considerably
• Exposure and processing factors effect the overall radiographic contrast