When should Cone Beam Computed Tomography (CBCT) be recommended?

When to Recommend Cone Beam Computed Tomography (CBCT)

CBCT should only be recommended when conventional 2D imaging techniques (such as periapical radiographs or orthopantomography) do not provide sufficient diagnostic information for treatment planning. 1

Primary Indications for CBCT in Dentistry

Dental Traumatology

• CBCT is indicated when clinical evaluation and primary radiographic investigations (periapical x-rays) are not sufficient for correct treatment planning in dental trauma cases 1
• Particularly useful for evaluating suspected root fractures and alveolar bone fractures, as it can confirm the presence of fractures and assess the fracture line on the buccal-lingual plane 1
• Helpful in diagnosing tooth luxation, which is often difficult to assess using two-dimensional imaging 1

Impacted Teeth Assessment

• CBCT is essential for assessing the relationship between third lower molars and the mandibular canal when panoramic imaging suggests contact with the canal 1
• Indicated for pre-surgical evaluation of third upper molars when orthopantomography suggests contact between the tooth roots and maxillary sinus floor 1
• Not recommended as an initial diagnostic examination for dental impaction - conventional imaging should be used first 1

Dental Morphology Anomalies

• When 2D imaging is insufficient to clarify the anatomical relationships of an anomalously shaped tooth with surrounding structures 1
• When the internal structure of dysmorphic dental roots needs better definition 1
• Not recommended as an initial diagnostic examination for morphological anomalies of teeth 1

Orthodontic Applications

• Consider CBCT to detect and evaluate the severity of root resorptions caused by impacted canines when conventional radiographs are insufficient 1
• For diagnosing the localization of impacted canines only when other available radiographs don't provide adequate information 1
• Not recommended for routine orthodontic diagnosis and treatment planning 1

Transarterial Chemoembolization (TACE)

• Highly recommended during TACE procedures for hepatocellular carcinoma to enhance treatment efficacy 1
• Provides better spatial resolution and can demonstrate fine hepatic arteries accurately 1
• Helps in identifying tumor-feeding arteries, evaluating chemoembolic material accumulation, and localizing target tumors 1

Advantages of CBCT

• Provides three-dimensional volumetric data in axial, sagittal, and coronal planes 2
• Radiation exposure dose is approximately 10 times less than conventional CT scans 2, 3
• Better spatial resolution than conventional CT due to smaller focal spot and larger matrix 1, 4
• Can show the exact location of anatomical structures to prevent non-target embolization 1

Limitations and Considerations

• CBCT exposes patients to higher radiation doses compared to conventional 2D radiographs 5
  • Depending on scan mode, CBCT radiation is about 3-6 times that of an orthopantomography, 8-14 times a posteroanterior cephalogram, and 15-26 times a lateral cephalogram 5
• Susceptible to motion artifacts from cardiac and respiratory movements due to longer scan times 1
• Should follow the ALARA (As Low As Reasonably Achievable) principle by using targeted imaging with reduced field of view to minimize radiation exposure 1
• Not recommended for detecting or evaluating the severity of external apical root resorption as it has no added value compared to orthopantomography 1
• Not indicated for inter-radicular miniscrew placements as it has no added value compared to periapical radiographs 1

Radiation Dose Considerations

• Standard CBCT imaging protocols produce effective doses (1.3-21.1 μSv) that are significantly lower than MDCT (9.1-204 μSv) 6
• Child doses are significantly greater than adult doses, requiring special consideration 6
• Reduced dose protocols can further lower radiation exposure by 36%-51% 6
• Shielding radiation-sensitive organs (especially thyroid) can reduce the effective dose considerably 5

In summary, while CBCT offers superior diagnostic capabilities for specific dental and maxillofacial conditions, it should be used judiciously and only when conventional 2D imaging techniques are insufficient for diagnosis and treatment planning, following the ALARA principle to minimize patient radiation exposure.