Dental Caries Detection Methods
Contour of the Surface
No cavitation or smooth cavity surroundings (1)
Cavitation with irregular border (2)
Distance from Lesion to Gingival Margin
More than 1.0 mm from the gingival margin (1)
Less than 1.0 mm from the gingival margin (2)
Color of the Lesion
Dark brown/black (1)
Light brown/yellowish (2)
Visual and Tactile Methods
Visual and tactile methods are the hallmark of detection of carious lesions.
Non-cavitated caries lesions are more prevalent than cavitated lesions in economically developed countries.
Non-cavitated caries lesions are more likely to be restored compared with sound tooth surfaces.
Non-cavitated lesions, especially on smooth tooth surfaces in young children, may serve as indicators of caries activity.
Inclusion of non-cavitated lesions may provide a better understanding of the mechanism of action of fluoride, sealants, and other preventive agents.
Inclusion of early signs of the caries process improves the precision of clinical trials of preventive agents.
Emphasis is being given to diagnostic criteria, which can detect incipient carious lesions.
Disadvantages of Visual Tactile Examination
May miss out an incipient lesion.
The criterion for detection of caries is not standardized.
The method of examination and criterion for diagnosis varies from individual to individual.
Probing depth and pressure is controversial.
Radiographic Methods
The carious process leads to demineralization of the affected area of the tooth, which appears radiolucent on the radiograph.
The presence of radiolucency in the tooth substance is considered as caries.
Radiographs have certain limitations; therefore, the combination of clinical examination along with the radiographic aid is considered mandatory for diagnosing caries.
The mere presence of radiolucency may be misleading.
Conventional Radiography
Periapical radiography
Bitewing radiography
Occlusal radiographs and panoramic radiographs are rarely employed in the detection of caries.
Panoramic views are employed for having a broader view of the oral cavity; however, the panoramic technique utilizes intensifying screen, which may hamper the finer details.
The occlusal technique does not determine the angulation of a tooth in that particular arch.
Periapical radiographs are useful for detecting changes in and around the tooth tissues, such as extent of caries, cervical margins of the restoration, alveolar crest height, lamina dura as well as the size of the pulp chamber.
The paralleling technique is considered superior to bisecting technique for detecting caries in both anterior and posterior teeth.
Bitewing radiographs are important to detect incipient lesions at the contact areas. With this technique, six to eight teeth in one radiograph can be visualized. The technique can be used for anterior as well as posterior teeth. The film is available in different sizes to suit the area to be radiographed.
Posterior bitewing radiographs are preferably utilized to detect interproximal caries.
Recurrent caries at the cervical margins is best observed in bitewing films, since the central ray is directed along the plane of the cervical areas.
Bitewing radiographs are useful in monitoring and evaluating the progress or arrest of dental caries.
Radiographic Appearance of Caries
Occlusal caries: Radiographs are not effective until the occlusal caries involves dentin. Once in dentin, the radiographic image shows a broad based thin radiolucent zone in the dentin with a little or no change apparent in the enamel.
A significant manifestation of occlusal caries in dentin is the presence of a band of increased opacity at the base of carious lesion near the pulp chamber. The white band represents the calcification within the primary dentin; such a band may not be evident in buccal caries.
Limitations of Radiographic Interpretation of Occlusal Caries
Difficult to detect caries in enamel because of superimposition of adjacent enamel over the fissures.
Lesions involving buccal grooves of molars are superimposed over the occlusal area and can simulate occlusal lesions.
A thin radiolucency at the dentino-enamel junction in occlusal caries, may be confusing with normal radiolucency in enamel and dentin.
Difficult to distinguish between occlusal caries and the internal resorption.
Proximal caries: A considerable loss of mineral content is mandatory before it becomes visible on a radiograph. The initial loss of mineral content, may be distributed in the broad proximal area, is not evident in radiographs. The actual depth of the lesion is always deeper than may be seen radiographically.
The white chalky appearance is the first evidence on the surface of enamel just below the contact point. The caries susceptible zone is 1.0 to 1.5 mm below the contact point, which is evident as a small radiolucent area below the contact area.
With the advancing lesion, the radiographic image is like a diffuse triangle with the base at the surface of the tooth. Once the lesion
Contour of the Surface
No cavitation or smooth cavity surroundings (1)
Cavitation with irregular border (2)
Distance from Lesion to Gingival Margin
More than 1.0 mm from the gingival margin (1)
Less than 1.0 mm from the gingival margin (2)
Color of the Lesion
Dark brown/black (1)
Light brown/yellowish (2)
Visual and Tactile Methods
Visual and tactile methods are the hallmark of detection of carious lesions.
Non-cavitated caries lesions are more prevalent than cavitated lesions in economically developed countries.
Non-cavitated caries lesions are more likely to be restored compared with sound tooth surfaces.
Non-cavitated lesions, especially on smooth tooth surfaces in young children, may serve as indicators of caries activity.
Inclusion of non-cavitated lesions may provide a better understanding of the mechanism of action of fluoride, sealants, and other preventive agents.
Inclusion of early signs of the caries process improves the precision of clinical trials of preventive agents.
Emphasis is being given to diagnostic criteria, which can detect incipient carious lesions.
Disadvantages of Visual Tactile Examination
May miss out an incipient lesion.
The criterion for detection of caries is not standardized.
The method of examination and criterion for diagnosis varies from individual to individual.
Probing depth and pressure is controversial.
Radiographic Methods
The carious process leads to demineralization of the affected area of the tooth, which appears radiolucent on the radiograph.
The presence of radiolucency in the tooth substance is considered as caries.
Radiographs have certain limitations; therefore, the combination of clinical examination along with the radiographic aid is considered mandatory for diagnosing caries.
The mere presence of radiolucency may be misleading.
Conventional Radiography
Periapical radiography
Bitewing radiography
Occlusal radiographs and panoramic radiographs are rarely employed in the detection of caries.
Panoramic views are employed for having a broader view of the oral cavity; however, the panoramic technique utilizes intensifying screen, which may hamper the finer details.
The occlusal technique does not determine the angulation of a tooth in that particular arch.
Periapical radiographs are useful for detecting changes in and around the tooth tissues, such as extent of caries, cervical margins of the restoration, alveolar crest height, lamina dura as well as the size of the pulp chamber.
The paralleling technique is considered superior to bisecting technique for detecting caries in both anterior and posterior teeth.
Bitewing radiographs are important to detect incipient lesions at the contact areas. With this technique, six to eight teeth in one radiograph can be visualized. The technique can be used for anterior as well as posterior teeth. The film is available in different sizes to suit the area to be radiographed.
Posterior bitewing radiographs are preferably utilized to detect interproximal caries.
Recurrent caries at the cervical margins is best observed in bitewing films, since the central ray is directed along the plane of the cervical areas.
Bitewing radiographs are useful in monitoring and evaluating the progress or arrest of dental caries.
Radiographic Appearance of Caries
Occlusal caries: Radiographs are not effective until the occlusal caries involves dentin. Once in dentin, the radiographic image shows a broad based thin radiolucent zone in the dentin with a little or no change apparent in the enamel.
A significant manifestation of occlusal caries in dentin is the presence of a band of increased opacity at the base of carious lesion near the pulp chamber. The white band represents the calcification within the primary dentin; such a band may not be evident in buccal caries.
Limitations of Radiographic Interpretation of Occlusal Caries
Difficult to detect caries in enamel because of superimposition of adjacent enamel over the fissures.
Lesions involving buccal grooves of molars are superimposed over the occlusal area and can simulate occlusal lesions.
A thin radiolucency at the dentino-enamel junction in occlusal caries, may be confusing with normal radiolucency in enamel and dentin.
Difficult to distinguish between occlusal caries and the internal resorption.
Proximal caries: A considerable loss of mineral content is mandatory before it becomes visible on a radiograph. The initial loss of mineral content, may be distributed in the broad proximal area, is not evident in radiographs. The actual depth of the lesion is always deeper than may be seen radiographically.
The white chalky appearance is the first evidence on the surface of enamel just below the contact point. The caries susceptible zone is 1.0 to 1.5 mm below the contact point, which is evident as a small radiolucent area below the contact area.
With the advancing lesion, the radiographic image is like a diffuse triangle with the base at the surface of the tooth. Once the lesion extends to the dentino-enamel junction(DEJ), it spreads laterally along the DEJ. The tip of the triangle points towards the pulp.
Factors Affecting Radiographic Interpretation:
Exposure factors: over exposure, underexposure.
Angulation of X-ray beam.
Processing errors: over development, under development.
Film artifacts: Scratches, finger prints.
Anatomic variations: Enamel pearls, dense bone islands.
Restorative materials: radiopaque restorative materials.
Advanced Radiographic Methods
Digital Radiography:
In digital radiography, the conventional film is replaced by a reusable electronic sensor. The image is displayed on a computer screen.
It reduces radiation dose for patients since it requires less radiation to produce an image.
The technique provides facilities for image enhancement, like contrast, brightness manipulation, and 3D reconstruction.
Advantages:
Reduction in radiation exposure.
Instant image acquisition.
Image enhancement.
Absence of film and processing chemicals.
Easy data management.
Tele-radiology and easy transfer of images.
Environment friendly.
Disadvantages:
High initial cost.
Subtraction Radiography
It shows the changes between two radiographs of the same area taken at different times.
It eliminates extraneous anatomical structures that may interfere with interpretation.
It increases the diagnostic sensitivity for detecting small changes in bone mineral density.
Cone Beam Computed Tomography (CBCT)
CBCT utilizes a cone-shaped X-ray beam to acquire volumetric data of the maxillofacial region.
CBCT provides three-dimensional images with high resolution and accuracy.
CBCT is considered superior to conventional radiography for detecting carious lesions, especially small occlusal caries.
Advantages
High resolution three-dimensional images.
Reduced radiation dose compared to conventional CT scans.
Accurate assessment of the size, shape, and location of carious lesions.
Disadvantages
Higher cost than conventional radiography.
Limited field of view in some CBCT units.
DIAGNOdent
DIAGNOdent is a laser fluorescence device used for detecting caries.
It uses a red laser light with a wavelength of 655 nm to scan the tooth surface.
When the laser light encounters carious lesions, it fluoresces.
The amount of fluorescence is measured by the device and displayed as a numerical value.
Higher values indicate a greater degree of caries.
Advantages of DIAGNOdent
Early detection of caries, especially in pits and fissures.
Non-invasive and painless procedure.
Quantitative assessment of caries.
Monitoring of caries progression or arrest.
Disadvantages of DIAGNOdent
False-positive results in the presence of plaque, calculus, or stains.
Limited use on smooth surfaces and proximal areas.
High cost of the device.
Quantitative Light-induced Fluorescence (QLF)
QLF is a non-invasive imaging technique that uses blue light to detect caries.
When blue light illuminates the tooth surface, it induces fluorescence.
The fluorescence is captured by a camera and analyzed by software.
QLF can quantify the mineral loss associated with caries.
Advantages of QLF
Early detection of caries.
Quantification of mineral loss.
Monitoring of caries progression or regression.
Objective assessment of caries.
Disadvantages of QLF
Susceptible to interference from extrinsic stains and plaque.
Limited penetration depth.
High cost of the equipment.
Electrical Caries Measurement
Electrical caries measurement is based on the principle that carious tissue exhibits different electrical properties compared to sound enamel.
The technique uses a probe to measure the electrical resistance or conductance of the tooth surface.
Lower resistance or higher conductance values indicate the presence of caries.
Advantages of Electrical Caries Measurement
Objective assessment of caries.
Detection of early caries.
Non-invasive procedure.
Disadvantages of Electrical Caries Measurement
Sensitivity affected by moisture, temperature, and probe pressure.
False-positive results in the presence of plaque or calculus.
Ultrasound
High