CBCT is useful for maxillofacial diagnosis as it allows observation of cross-sectional changes with no geometric distortion and overcomes anatomical noise. It provides an accurate 3D representation of lesion extent, involvement of adjacent structures, and internal structures. CBCT has a sensitivity of 91% for bone carcinoma diagnosis, similar to MRI. It is optimal for diagnosing benign lesions due to its better spatial resolution, lower cost, and lower radiation dose compared to other imaging modalities. CBCT should be ordered after clinical examination if additional information is needed to aid diagnosis, and the appropriate scan volume and voxel resolution should be selected.

1. CBCT in Maxillofacial Diagnosis
Presented by
Dr. Abhishek Gupta

2. Learning Objectives
• Fundamentals of diagnostic image analysis
• Analysis of CBCT images: identification and description of
abnormalities
• Diagnosis and Differential diagnosis of different pathologies
presented on CBCT

3. Role of Diagnostic Imaging
 Assist and/or confirm a suspected diagnosis
 Guide for appropriate management
 identify surgical parameters:
• pathologic margins,
• involvement of important anatomical structures such as
IANC
 determine the effectiveness of a specific management strategy
treatments with periodic assessment

4. Role (advantage) of CBCT in
diagnosis
• Observe cross-section changes
• No geometric distortion
• Overcomes anatomical noise
• View/examine an area of concern/potential surgical site in 3D
• accurate representation of:
Lesion extent/margins/borders
Involvement of adjacent anatomic structures
Internal structure:
- Septae / peripheral crenations
Presence and degree of root resorption (Buccal/Lingual)

5. Role (advantage) of CBCT in
diagnosis
• For bone carcinoma
– Sensitivity is 91%, next to MRI [94%]
– Specificity is 100% [as MRI & MDCT]
• Optimal for benign lesions
– better spatial resolution
– availability
– lower financial cost
– lower radiation dose

6. When to order a CBCT scan?
• Follow ALARA principle
• Keep in Mind that CBCT is for:
– Hard tissue: suspected lesion involves bone/teeth
– Soft tissue (in special cases only) : Paranasal sinuses/
airway (obstruction)

7. When to order a CBCT scan?
• After through clinical examination & evaluation of available
radiographs
• Additional information aid to diagnosis?
YES
• Then, What kind of scan is required?
– FOV [40 mm × 40 mm to 150 mm × 150 mm]
– Voxel resolution [0.08 to 0.4 mm]
• Follow-up after treatment/surgery

8. How to avoid & manage errors in
CBCT scan
• Follow manufacture's instructions
• Instruct patient adequately to avoid any motion
• Quick review of scan volume (check for errors like motion:
blurred images or double margins)
• Metal artifacts – sunray appearance
– most frequent (crowns)
‽ detection of crown and root fractures,
‽ early periodontal defects
‽ other defects adjacent to metallic restorations

9. limitations of CBCT Imaging
• low contrast resolution.
• NOT suited for:
– Differentiation of the intralesional contents (e.g., fluid vs.
tumor)
– Lesion extension through cortical perforation
– Adjacent soft tissue reaction (e.g., cellulitis associated with
osteomyelitis)
– Intra-articular disorders (e.g., temporomandibular disc
position, synovitis)