Radiographic Interpretation of
Dental Disease
Dental Caries Interpretation
• Detection of Dental Caries:
• Both careful clinical examination & a
radiographic examination are necessary.
Radiographic examination helps the dentist to:
1-Identify the carious lesions that are not visible
clinically.
2-Allow evaluating the extent & severity of
carious lesions.
Clinical Examination
• The probe used as a tactile device to detect the
presence of any changes in consistency (catches or
tug-back) in the pits, groves, fissures of the teeth.
• Some teeth with dental caries exhibit a discolored
area or a cavitation, whereas the others have no
visible changes.
• Caries that occur between the teeth may be difficult
or impossible to be detected clinically, in such
cases the radiographs play an important role.
• Radiographic Examination:
1. The bitewing radiograph is the radiograph of
choice for evaluation of caries because it
provides the dental professional with
diagnostic information that cannot be
obtained from any other source.
2. A periapical radiograph using the paralleling
technique can be used for evaluation of
dental caries.
Factors Affecting the Caries Interpretation
• Technical errors results in non diagnostic radiograph, e.g.
incorrect horizontal angulation lead to overlapping & obscured
the proximal caries.
• Incorrect exposure factors, like incorrect exposure time, kVp &
mA resulted in films that too light or too dark thus its useless in
dental caries detection.
Radiographic Classification of Caries
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Interproximal caries.
Occlusal caries.
Buccal caries.
Lingual caries.
Root caries.
Recurrent caries.
Rampant caries.
Radiation caries
Interproximal Caries
• It is found between two adjacent teeth, its seen
at or just below (apical to) the contact point.
This area is difficult if not impossible to
examine clinically.
Interproximal Caries
It follows the
path of dentinal
tubules
Interproximal caries classified according to its severity
• Incipient caries, extends less than half way through the
thickness of enamel (seen in the enamel only).
• Moderate caries, extends more than halfway through the
thickness of the enamel but dose not involve the DEJ (seen in
the enamel only).
• Advance caries, extends to or through the DEJ & into dentin
but dose not extend through the dentin more than half the
distance toward the pulp (affects both enamel & dentin).
• Severe caries, extends through enamel & through the dentin
more than half the distance toward the pulp (involve both
enamel & dentin) and may clinically appear as cavitation(or
hole) in the tooth.
Occlusal Caries
A thorough clinically examination is the method of
choice for the detection of occlusal caries. Because of
superimposition of dense buccal & lingual enamel cups,
early occlusal caries is difficult to detect on a dental
radiograph
The first radiographic sign is a dark line between
enamel and dentin. It follows the enamel rods.
Classification of Occlusal caries
• Incipient caries, cannot be seen on a dental
radiograph & must be detected clinically with dental
probe.
• Moderate caries, extends into dentin & appears as a
very thin radiolucent line located under the enamel of
the occlusal surface.
• Severe caries, extends into dentin & appears as a
large radiolucency under the enamel of the occlusal
surface of the tooth, clinically appears as a cavitation
in a tooth.
Buccal & Lingual Caries
• *Buccal caries involve the buccal tooth surface.
• *Lingual caries involve the lingual tooth surface.
Because of superimposition of the densities of normal
tooth structure, they are difficult to be detected by the
dental radiograph & are best detected clinically.
Radiographically these carious lesions appear as a
small circular radiolucent area.
Root Surface Caries
• Clinically: It is easily detected on exposed
root surface.
• Radiographically: It appears as a cupped-out
or crater-shaped radiolucency just below the
CEJ. It doesn't occur in areas covered by a
well attached gingival.
• It may be confused with cervical burnout.
Recurrent Caries
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Secondary or recurrent caries occurs adjacent to a
pre-existing restoration due to:
1. Inadequate cavity preparation.
2. Defective margins.
3. Incomplete removal of caries prior to the placement
of restoration.
• Radiographically: appears as a radiolucent area just
beneath a restoration, occurs most often beneath the
interproximal margins of a restoration.
Recurrent Caries
Rampant Caries
• The term rampant means growing or spreading.
• It is an advanced & severe caries that affects
numerous teeth.
• It is seen in children with poor dietary habits or in
adults with a decreased salivary flow.
Radiation caries
• Resulting from Xerostomia caused by head
and neck radiation therapy.
Radiographic interpretation of dental caries is
not always straightforward, it is often
complicated by two additional radiographic
shadows:
• Radiolucent cervical burn-out.
• Radiopaque zone beneath amalgam
restoration.
Radiolucent Cervical Burn-Out
Radiopaque Zone beneath Amalgam
Restorations
• It has been shown with time, tin & zinc ions are released into
the underlying demineralized dentine producing radiopaque
zone which follow the s-shape of the dentinal tubules. The
normal dentin on either sides appear more `radiolucent by
contrast, this more radiolucent normal dentin may simulate the
shadow of caries & lead to difficult diagnosis.
Limitations of Radiographic Diagnosis of
Caries
1. Carious lesions are usually larger clinically than they appear
radiographically & very early lesions are not evident at all.
2. Technique variations in film & x-ray beam position can affect
the image of the carious lesion (incorrect horizontal
angulation make carious lesion confirm in the enamel to be
progressed into dentin).
3. Exposure factors can affect the overall radiographic contrast &
thus affect the appearance or size of carious lesions on the
radiograph.
4. Superimposition & two dimensional image
mean that the following features cannot always be
determined:
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The exact site of a carious lesion, e.g. buccal or lingual
The bucco-lingual extent of a lesion.
The distance between the carious lesion & pulp horns (two
shadows can appear to be close together or even in contact
but they may not be in the same plane).
The presence of an enamel lesion (density of the overlying
enamel may obscure the zone of decalcification).
The presence of recurrent caries (existing restorations may
completely overlie the carious lesion).
Radiographic Assessment of
Restorations
• The important features to note include,
– the type & radiodensity of the restorative material,
• Amalgam.
• Cast metal.
• Composite or classionomer material.
– Over contouring.
– Overhanging ledges.
– Under contouring.
– Negative or reverse ledges.
– Presence of contact points.
– Adaptation of the restorative material to the base of the cavity.
– Marginal fit of cast restorations.
– Presence or absence of lining material.
– Radiodensity of lining material.
Assessment of the Underlying Tooth
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These include:
Recurrent caries.
Residual caries.
Radiopaque shadow of released tin & zinc ions.
Size of the pulp chamber.
Internal & external resorption.
Presence of root filling material in the pulp chamber.
Presence & position of pins or posts.