9 - Justification & Interpretation: Caries & Periapical Pathology

Question 1

ALARP - stands for?

Answer 1

as low as reasonably practicable

Question 2

justifying radiographs: balance between?

Answer 2

information desired and radiation dose to patient

Question 3

carious lesions can only be detected radiographically when? what other requirements of the radiograph needed?

Answer 3

there is sufficient demineralization

• must be distinguishable from enamel and dentine
• film must be well-exposed and well processed
• optimum viewing conditions

Question 4

recommended techniques for diagnosing caries?

Answer 4

• bitewings (usually horizontal)

- paralleling periapicals

Question 5

bitewing radiographs: what to do if there is periodontal bone loss as well as possible caries?

Answer 5

consider vertical bitewings

Question 6

what can be mistaken for caries?

Answer 6

• cervical burnout or translucency
• visual perception - problem of contrast below dense metallic restoration
• air/lip shadow in premolar region
• dentine surrounding radio-opqaue zone under amalgam
• radiolucent restorations

Question 7

limitations of caries diagnosis on radiographs?

Answer 7

• overlap:
  i. technique
  ii. anatomy
• exposure factors
• 2D image

Question 8

paralleling techniques: advantages?

Answer 8

• accurate images
• reproducible by different operators
• relative positions of film, teeth and xray beam always maintained

Question 9

bitewing radiograph - how often to do on:
high risk child?
moderate risk child?
low risk child?+ child with permanent teeth
adults?

Answer 9

• 6 monthly
• annually
• 12-18 months
• 24 months
• around 24-36 months if low risk. check health, medication & diet

Question 10

describe the trabecula pattern of the mandible and maxilla

Answer 10

mandible: thick, close together, horizontally aligned
maxilla: finer, more widely spaced, no obvious alignment pattern

Question 11

radiology and periradicular disease: 3 most important features for interpretation are?

Answer 11

1. radiolucent line representing the PDL space
2. radiopaque line representing the lamina dura
3. trabecula pattern & density of surrounding bone

Question 12

the 3 keys to interpreting radiographs in periradicular areas are limited due to?

Answer 12

• personal variation
• contrast
• resolution
• superimposition

Question 13

initial acute inflammation - radiographic appearance?

Answer 13

• no apparent changes

- possible widening of PDL space

Question 14

initial spread of inflammation - radiographic apperance?

Answer 14

loss of lamina dura at apex

Question 15

further inflammatory spread - radiographic appearance?

Answer 15

periapical bone loss

Question 16

initial chronic inflammation - radiographic appearance?

Answer 16

• no bone destruction seen

- dense sclerotic bone periapically (sclerosing/condensing osteitis)

Question 17

chronic inflammation - long standing: radiographic appearance?
radiolucency sometimes described as?

Answer 17

• circumscribed, well defined, radiolucent area periapically with sclerotic bone surrounding
• rarefying osteitis