RADIOGRAPHIC INTERPRETATION OF DENTAL CARIES

DRG. SHANTY CHAIRANI

DENTAL CARIES

Radiographic examination use :1. Bitewing Film

2. Periapical film

3. Panoramic (but it has a limited diagnostic value) Because the carious process results in

demineralization, the affected area of the tooth is more radiolucent (or less radiodense) than the unaffected portions of the tooth.

Approximately 50 % demineralization is required for radiographic detection of a lesion

Radiographs is used to aid detection of carious lesions.

Advanced carious lesions of the occlusal, cervikal and other exposed portions of a tooth are not difficult to diagnose by clinical examination.

The purpose of a radiograph, therefore, is to diagnose early carious lesions or those which lie hidden under restorations, or in the interproximal areas and to know the extent of the carious lesion.

Factors affecting appearance of caries:

Buccolingual thickness of tooth. The thicker the tooth, the more difficult it is to see the extent of the caries.

Two-dimensional film. Cannot see the extent of carious involvement in a buccolingual direction.

o X-ray beam angle (horizontal or vertical). This is especially important when trying to identify recurrent caries, since changes in angulation may cause the superimposition of the existing restoration with the carious lesion.

o Exposure factors. Caries detection is improved with a lower kVp setting, which provides a higher contrast. If the density of the film is too light or too dark, the diagnostic potential of the film is limited.

I

M = Moderate (Stage II)

I = Incipient (Stage I)

A = Advanced (Stage III)

S = Severe (Stage IV)

Caries Classification

S

AMA

IncipientModerateAdvanced

Interproximal Caries(Incipient)

I

Up to half the thickness of enamel

Usually not restored unless patient has high level of caries activity (high risk). Treat with fluoride.

The arrow points to incipient lesion on the distal #10

M

Interproximal Caries(Moderate)

More than halfway through the enamel (up to DEJ)

The bottom arrow points to a moderate lesion on the distal of # 20. The upper arrow points to one of several incipient lesions on the molar and premolars.

AA

Interproximal Caries(Advanced)

Advanced lesion identified by arrows.

Advanced lesion

More than halfway through the dentin

S

Interproximal Caries(Severe)

Severe lesion

Severe lesion

Occlusal Caries

Must have penetrated into dentin Diagnosed from clinical exam May be seen as thin radiolucent

line or cup-shaped zone underlying occlusal enamel, but difficult to see on radiographs unless lesion is large.

Occlusal caries

Occlusal caries

Buccal/Lingual Caries

Should be identified from clinical exam. On a dental radiograph, caries that

involves the buccal or lingual surface will appear as a small, circular radiolucency in middle of tooth , although it is not very radiolucent. 

In order to determine the location of the lesion, a clinical examination with an explorer is necessary.

Depth can not be determined radiographically.

Lingual caries (Can’t tell whether it’s buccal or lingual from one radiograph

Buccal caries with severe interproximal caries on # 12

Root Caries

On a dental radiograph, root surface caries appear as a cupped-out or crater-shaped radiolucency just below the cemento-enamel juction (CEJ).  Early lesions may be difficult to detect on a dental radiograph.

Usually found on older individuals with prominent recession and/or periodontitis. May have xerostomia due to medications.

May be confused with cervical burnout.

Root caries

Root caries

Cervical Burnout

o Cervical burnout is an apparent radiolucency found just below the CE junction on the root due to anatomical variation (concave root formation posteriorly) or a gap between the enamel and bone covering the root (anteriorly).

Cervical burnout appears as a collar or wedge-shaped radiolucency on the mesial and distal root surfaces near the CEJ of a tooth and may be confused with root caries. 

o The differences between cervikal burnout and root/cemental caries :• The area of relatively radiolucency in the

cervikal burnout occurs between the part of the root covered by alveolar bone and the enamel-covered crown.

• This phenomenon can be found in all the teeth that are projected in the film, usually in premolars which size are small.

But this radiolucency usually disappears when another film of the region is examined.

o Caries does not occur on the root of the tooth unless there is loss of alveolar bone and gingival tissue due to recession or periodontitis.

Cervical burnout

Posterior cervical burnout. The invagination of the proximal root surfaces allow more x-rays to pass through this area, resulting in a more radiolucent appearance on the radiograph. X-rays directed at a different angle usually pass through more tooth structure and the radiolucency disappears.

Radiolucency seen at left (arrow) disappears on periapical film of same tooth. This is cervical burnout.

bone level

Anterior cervical burnout. The space between the enamel and the bone overlying the tooth will appear more radiolucent than either the enamel or the bone-tooth combination.

Cervical burnout in the anterior region due to gap between enamel (red arrows) and alveolar bone over root (blue arrows).

Recurrent Caries

Radiolucency extends into the dentin (with/without extends to pulp) adjacent to an existing restoration.

May be due to unusual susceptibility to caries, poor oral hygiene, failure to remove all of the caries during cavity preparation, a defective restoration or a combination of the above.

Recurrent caries

Recurrent caries

Rampant Caries

Extensive and rapidly progressing caries usually found in children and teens with poor diet and inadequate oral hygiene

Found in head/neck radiation therapy patients with xerostomia

Fluoride used for control

Radiation Caries

Before radiation

1 year after radiation

Mach BandOptical illusion giving appearance of increased radiolucency at the junction of differing tissue densities, such as enamel and dentin. If you block off the enamel with a fingernail, the radiolucency will disappear if due to the mach band effect. If the radiolucency persists, it may be caries.