Digital Dental Radiology: Techniques and Indications

The ALARA principle guiding every radiological choice in dentistry, the radiation dose comparison between panoramic X-ray, CBCT and traditional CT, and when cone beam tomography is truly indicated.

Every choice in dental radiology, from a simple intraoral X-ray to cone beam computed tomography (CBCT), is governed by the ALARA principle — As Low As Reasonably Achievable, meaning the lowest radiation dose reasonably obtainable consistent with the diagnostic information needed. In Italy this principle is implemented at the regulatory level by Legislative Decree 187/2000, which requires the clinician to justify every radiographic exam prescribed and optimize its technical parameters to minimize the dose absorbed by the patient while maintaining adequate diagnostic quality.

Digital sensors, now standard in most practices, offer a direct advantage precisely in ALARA terms: they're more sensitive to X-rays than traditional analog film and therefore require shorter exposure times for equal image quality, alongside the practical advantages of immediate electronic archiving, sharing with other professionals and the possibility of digital image processing to improve diagnostic readability.

CBCT is today the gold standard for three-dimensional imaging in dentistry and maxillofacial care, with applications ranging from implant planning to assessing complex endodontic pathology, through to oral surgery and orthodontics. Compared to traditional spiral CT, CBCT performs a single rotation around the patient's head instead of multiple rotations, resulting in a significantly lower radiation dose: dosimetric studies report CBCT doses on the order of 10-60 microsieverts depending on the field of view (FOV) selected, versus roughly 2,100 microsieverts for a traditional CT of the same anatomical area.

This doesn't mean, however, that CBCT is without radiological impact: compared to a simple panoramic X-ray, the CBCT dose is still 4 to 42 times higher, depending on the technical settings used. This is why its prescription must always be justified by a genuine diagnostic need that conventional two-dimensional radiography couldn't meet, also selecting the smallest FOV possible consistent with the area to be investigated — a principle that, consistent with ALARA, further reduces the dose absorbed by the patient without compromising diagnostic usefulness.

On Oralzon you'll find intraoral digital sensors, panoramic radiographic systems and radioprotection devices to build a complete radiological protocol compliant with current safety principles.