10 - Caries

Question 1

does xray shadow formation depend on density or composition

Answer 1

DENSITY! NOT composition

Question 2

A demineralized region of tooth structure that has partially remineralized so that the total mineral content compared to sound tooth has not been reduced significantly [will OR will not] produce a lesion shadow.

Answer 2

will not

Question 3

there must be what percent mineral loss for lesion to be radiographically apparent

Answer 3

30-35% mineral loss

Question 4

[long/short] path absorbs more radiation - less dense shadow

Answer 4

LONG

Question 5

[long/short] path - less absorption. denser shadow

Answer 5

SHORT

Question 6

the greater the mass around the carious lesion the [more/less] radiation hits the sensor

Answer 6

LESS

Question 7

demineralization [increases or decreases] shadow density

Answer 7

INCREASES

Question 8

remineralization [increases or decreases] shadow density

Answer 8

DECREASES

Question 9

xray beam direction is relative to what of lesion affects the lesion’s shadow

Answer 9

relative to LONG AXIS

Question 10

parallel to long axis (horizontal) = [denser or less dense]

Answer 10

denser (Darker)

Question 11

inclined to long axis (up or down) = [denser or less dense]

Answer 11

less dense (less dark)

Question 12

___: Represents rapid severe progressive caries with no remineralization therefore high mineral loss & lucency

Answer 12

Active caries

Question 13

Partially remineralized lesions (“X-ray” scars)

Answer 13

arrested caries

Question 14

can you differentiate between active and arrested caries in one image? how do you do it?

Answer 14

cannot differentiate - another image at different time period is required to differentiate

Question 15

what is the recommended interval between imaging examinations?

Answer 15

varies substantially -> 6 months-higher risk

Question 16

lesion shadows often underestimate what

Answer 16

depth of demineralization (don’t confuse with bacterial infection)

Question 17

shallow enamel only lesions can produce what?

Answer 17

shadows in enamel or throw them over the dentin. these are not dentin lesions

Question 18

why is it not possible to reliably judge the depth of lesion with xray

Answer 18

due to variability of xray beam direction and degree of demineralization

Question 19

when can you detect change over time?

Answer 19

if irradiation geometry and exposure factors are constant between examinations

Question 20

how do you know if geometry or exposure has changed

Answer 20

look for interproximal contact overlap, cusp height, and interdental space consistency

Question 21

how can you classify lesion activity - progression, stasis, remineralization?

Answer 21

classifying enamel into equal halves and dentin into thirds - E1, E2, D1, D2, D3

Question 22

what are examples of diagnostic pitfalls

Answer 22

1. cervical burnout
2. CEJ
3. periodontal ligament space

Question 23

what is the least dense region between CEJ and alveolar bone crest

Answer 23

cervical burnout

Question 24

how to determine between interproximal caries or cervical burnout

Answer 24

Interproximal caries - Occur in the region that extends
between the contact points of teeth apically to near the free
gingival margin. Irregular margins, discontinuity of the tooth
surface
Cervical burnout - Just apical to the CEJ

Question 25

VISUAL AND PERCEPTUAL ARTIFACT arises as a result of the differential stimulation and inhibition of neighboring receptors in the retina.

Answer 25

mach-band effect

Question 26

what does pit and fissure enamel caries look like on BW

Answer 26

too little loss of Ca relative to bulk of tooth to cast a shadow

Question 27

what does pit and fissure dentin caries look like on BW

Answer 27

Pit and fissure dentin caries - may cast a shadow but dependent on degree of demineralization relative to tooth bulk. Overall 50% dentin lesions - shadows. As lesions get bigger, chance of shadow 1

Question 28

what % of interproximal enamel caries produce shadows? what is its diagnostic accuracy

Answer 28

15-25%; 50%

Question 29

can you replace extraoral BW with intraoral BW? when do use it?

Answer 29

NO! not a replacement for intraoral! Only can be used when it is impossible to obtain intraoral images E.g. Uncooperative patients, severe gagging, large mandibular tori

Question 30

what caries is most likely to stop and not need a filling

Answer 30

non-cavitated

Question 31

what caries is more likely to progress

Answer 31

cavitated

Question 32

what is capable of converting from non-cavitated to cavitated

Answer 32

sharp probes

Question 33

when can caries progression stop from non-cavitated to dentin cavitated

Answer 33

stop at any stage

Question 34

Non-progressing enamel caries - surface layer has remineralized - body of the lesion is cut off from saliva with supersaturated Ca and PO- permanent radiographic "scar"

Answer 34

BW radiographic scars

Question 35

are BW radiographic scars a threat to the tooth

Answer 35

NO

Question 36

who has higher radiation dose - BW or CBCT

Answer 36

CBCT

Question 37

why is the use of CBCT discouraged?

Answer 37

requires more time for reading the images

Question 38

to asses caries activity over time, what must you look for

Answer 38

irradiation geomatry changes producing false changes in depth