CBCT, what’s the harm and should it be routinely in orthodontics?
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Join me for a summary of CBCT use in orthodontics, where I look into the current risk of cancer with CBCT use, the difference it can make to treatment planning, and the 3 most common incidental findings orthodontists should be aware of. This was one my highlight lectures from last years British Orthodontic Conference by Consultant Dental Radiologist, Simon Harvey.
How much radiation comes from dental CBCT, medicine?
Effective dose of modern machines:
- Dose from full DPT with a digital system = 20-25µSv
- KAVO, MoritaX800 4 x 4cm = 16uSv
- FDA values of CT scans across the boy from Lubar 1500uSv – Heart 16000uSv
FACT 1 – effective dose in dental imaging are far below the rest of medicine
Background radiation
- Terrestrial radiation
- Cosmic radiation
- Flight London – New York 56uSv – cancer UK ‘does not effect risk of cancer, even for frequent flyers’, 4uSv per hour
- Pilots do not have an increased risk of cancer
UK 3000 uSv annually
FACT 2 – EFFECTIVE DOSES IN DENTAL IMAGING ARE FAR BELOW THE NATURAL BACKGROUND RADIATION
American Association of Physicist in Medicine AAPM
“evidence supporting increased cancer incidence or mortality from radiation doeses below 100mSv is inconclusive” – cancer incidence and mortality from the use of diagnostic imaging are highly speculative, discourage these prediction of hypothetical harm
FACT 3 EFFECTIVE DOSES IN DENTAL IMAGING ARE SO LOW, THEY DO NOT CAUSE CANCER
Clinicians improved confidence and consistency in treatment planning decisions.
Impacted canine:
- 3 radiographs – namely occlusal view, opg , periapical = still not confident about prognosis.
- CBCT = clear follicle and impacted canine proximity to adjacent tooth, = easily make up the decision estimating prognosis
- 22%-44% change of plans Hodges 2013 Stoustrup 2024 change in treatment plans of impacted teeth. The majority related to change in planning, with approximately 10-20% a change in exposure Vs extraction. Keener 2023
- Cleft – quantification of bone defect volume for grafting and localisation of ectopic teeth
- Surgery – location of important anatomical structures
3 Common incidental findings for orthodontists
- Dense bone island-
- Radiopacity with no radiolucent halo
- Mandibular premolar region
- Harmless, may resorb roots if contact it
- Sinus mucosal thickening
- Antrum floor intact
- Only concern if 5mm+
- Trabecular pattern
- Around inferior dento-alveolar canal
- No corticated boarder
- normal in children, technical reason is physiologic response as more RBC’s are developing surrounding that area.
Pregnant women – yes as not irridating pelvic reason, CBCT beam is horizontal so no risk
Conclusion
- CBCT superior for resorption, material change to treatment plans and improve confidence of the orthodontists
- No recommendation for taking full mouth CBCT instead of DPT ahead of starting every orthodontic treatment as routine and x rays should never go hand in hand
- Small volume CBCT does is so low it doesn’t cause cancer
Contributions
Contents: Shanya Kapor
Edited and produced: Farooq Ahmed
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