What imaging modalities are recommended for evaluating dental caries?

Imaging Modalities for Dental Caries Evaluation

Bitewing radiography is the primary radiographic examination of choice for detecting dental caries in both primary and permanent teeth, with periapical radiographs indicated as supplementary imaging for high-risk patients or when pulpal involvement is suspected. 1

Primary Imaging Methods

Visual Inspection

• Serves as the initial assessment method for dental caries detection
• Particularly effective for accessible surfaces and primary dentition
• Detects the majority of occlusal caries lesions in low-risk adult populations 2
• Should be performed meticulously as part of the standard examination

Bitewing Radiography

• First-line radiographic method for caries detection in both primary and permanent teeth 1
• Provides adequate visualization of the entire crown of permanent teeth
• Superior sensitivity compared to visual inspection alone, especially for interproximal caries 3
• When combined with visual examination, correctly classifies 82% of first permanent molars and 91% of second primary molars 3

Supplementary Imaging Methods

Periapical Radiography

• Indicated as a supplementary examination for:
  • High caries risk patients
  • Cases with suspected pulpal or apical involvement
  • Presence of fistula (with gutta-percha cone inserted into fistula) 1
• Should be taken using paralleling technique with film holders and beam aiming devices

Cone Beam Computed Tomography (CBCT)

• Not recommended as first-line examination for caries detection
• May be used for suspect or unclear cases after traditional intraoral examination
• Better highlights periapical disease but delivers higher radiation dose 1
• Should be reserved for complex cases where conventional imaging is inconclusive

Adjunctive Methods

Fiber-Optic Transillumination (FOTI)

• May aid the diagnostic process
• Comparable accuracy to detailed visual inspection for occlusal caries 4
• Shows good correlation with histology (correlation coefficient 0.65-0.73) 4
• As accurate as detailed visual inspection in detecting occlusal caries

Near-Infrared Light Transillumination (NIR-LT)

• Provides limited additional diagnostic benefit beyond visual inspection 1
• X-ray free alternative that might be preferred in certain clinical situations 2
• Combined with visual inspection, identifies 95.7% of all enamel and dentin caries lesions on occlusal surfaces 2

Clinical Decision Algorithm

1. Begin with visual inspection for all patients
2. Add bitewing radiography for:
   • Interproximal areas that cannot be adequately visualized
   • Patients with moderate to high caries risk
   • When occlusal caries is suspected but not definitively diagnosed visually
3. Add periapical radiography when:
   • Pulpal involvement is suspected
   • Patient has high caries risk
   • Fistula is present
4. Consider adjunctive methods (FOTI, NIR-LT) when:
   • Additional confirmation is needed
   • Radiation exposure is a concern
   • Results from visual and radiographic examination are inconclusive

Important Considerations and Pitfalls

• Radiation protection (thyroid collar) should always be used, especially for pediatric patients 1
• Superimposition of bony structures in posterior areas may obscure periapical pathology, requiring careful radiographic interpretation
• Restorations with established and active lesions at margins when visually inspected often require removal and retreatment, as they have a greater chance of exhibiting recurrent or residual lesions on radiographic examination 5
• Laser fluorescence and similar technologies are not currently viable alternatives to radiographic diagnostics due to insufficient scientific evidence 1
• The combined use of visual inspection with either NIR-LT or bitewing radiography identifies over 94% of all caries lesions on occlusal surfaces 2

Remember that while bitewing radiography is the primary radiographic method, the most recent consensus from ORCA-EFCD (2024) confirms that visual examination should be the first-choice method for detection and assessment of caries lesions on accessible surfaces, with intraoral radiography (preferably bitewing) recommended as an additional method 6.