radiographic interpretation of dental caries

lecture given 4/6/2026

if a new adult patient comes into your office and has no visible pathology and closed contacts, what radiographs should you take, if any?

pano and bitewings

what kind of electron interaction do we want to get radiographs?

photoelectric aka characteristic radiation

electrons interact with inner shell electrons

t/f demineralization of tooth structure is a dynamic process by an infectious disease

true

what factors contribute to caries?

bacteria- plaque or biofilm, strep mutans

diet- fermentable carbohydrates

what factors prevent caries?

hygiene- remove or interrupt bacterial plaque

fluoride- remineralizes outer surface of tooth and makes it more resistant to demineralization

what are the steps of caries detection?

patient history

clinical exam- visual, tactile, caries detection dye, transillumination, electronic caries monitor

radiographic assessment *done last!

what is the ranking of diagnostic value of radiographs, from most to least?

bitewing, periapical, pano, CBCT

a?

class I, occlusal surfaces

b?

class II, proximal surfaces

c? left lol sorry

class III

c? right

class IV

d?

class V, buccal and lingual surfaces or root surfaces

e?

class VI

where are interproximal caries likely to develop?

the most superior zone of contact to the papilla

interproximal caries- incipient

caries suseptible zone

do not extend into DEJ

triangle with broad base at outer surface

what are the arrows pointing to?

incipient interproximal caries

how to interproximal caries spread?

along the DEJ

into dentin- creates a second triangle at the base of the DEJ

in some cases, lesion may appear not to have penetrated enamel

what do these images have?

interproximal caries (not incipient)

are these caries or restorations with radiolucent material?

caries

are these caries or restorations with radiolucent materials?

restorations with radiolucent materials

what is this arrow pointing at?

secondary caries

large occlusal caries

easily observed, appear as large/dark circles in the crown

pulp exposure cannot always be determined

what are these?

large occlusal caries

small occlusal caries

not very effective at detecting, may be seen as thin radiolucent line or cup shaped zone underlying occlusal enamel

minimum or no changes in enamel

what are these arrows pointing at?

small occlusal caries

rampant caries

affects almost all teeth- usually caused by radiation

root surface caries

cratering on the roots of the teeth, involving cementum

buccal/lingual/proximal

saucer like radiolucency

may be confused with cervical burnout

can you have root surface caries without exposed roots?

no!

what are the arrows pointing to?

root surface caries

what are the arrows pointing at?

cervical burnout

how can you tell if its cervical burnout or caries?

there is no bone loss, it affects multiple teeth, and if the angle of the radiograph changes the radiolucency is gone

recurrent caries

around the margin of existing restorations, spreads in a natural way

what do these images have?

recurrent caries

what are these arrows pointing at?

a restoration with a radiolucent liner- the box is too sharply defined to be a natural process

what are diagnostic confounders?

pits and fissures, cervical burnout, mach band effect, dental anomalies like hypoplastic pits and concavities produced by wear

mach band effect

an optical illusion where the human eye perceives faint light and dark bands at the boundary of two shades of gray, even if the transition is gradual

what is shown in the non-restored premolar?

mach band effect- the faint dark line under enamel is not caries, it is an ~optical illusion~

if you change angulation of radiograph or CBCT it would disappear

cervical burnout

apparent radiolucency below the CEJ due to anatomy or a gap between the enamel and bone covering the rooth

no root caries unless there is alveolar bone loss

what is the arrow pointing to?

hypoplastic pit

t/f the extent of caries you see on a radiograph is the same as what it will be when you drill

false- has to be significantly decalcified to be visible on x ray

t/f having overlap makes it easier to see interproximal caries

false- impossible