There have been several studies comparing the efficacy of detecting proximal caries using conventional radiography and CBCT.
It is important to keep in mind most of these studies were done on the permanent dentition.
Senel et al. reported there was no significant difference in the detection of proximal caries in permanent teeth using visual inspection, film, CCD, PSP plates and CBCT (15).
Akdeniz et al. compared the accuracy of proximal caries depth measurements between limited CBCT and conventional 2-D imaging using storage phosphor and film radiography. Although the study concluded LCBCT seems to offer advantages over conventional 2-D techniques for determining the depth of small proximal carious lesions it is important to note that none of the teeth in the study were restored or in contact with restored teeth. Restorations particularly of dense material such as amalgam can cause artifacts and compromise the final diagnosis(16).
In an in-vitro study 257, non-filled approximal surfaces from human permanent premolars and molars were recorded by two intraoral digital receptors, a storage phosphor plate (Digora Optime, Soredex) and a solid-state CMOS sensor (Digora Toto, Soredex), and scanned in a cone
beam CT unit (3D Accuitomo FPD80, Morita) with a FOV of 4 cm and a voxel size of 0.08 mm.
A significantly higher sensitivity was obtained by all observers with CBCT which was not compromised by a lower specificity. The authors concluded CBCT was much more accurate in the detection of surface cavitation in approximal surfaces than intraoral receptors. A CBCT examination performed for other reasons should also be assessed for approximal surface cavities in teeth without restorations (17).
In a recent systematic review by Horner et al. it was reported most studies relating to CBCT and caries detection are based on in Vitro research most of which showed little difference in diagnostic accuracy when CBCT imaging was used compared with intraoral radiography. All existing guidelines do not recommend using CBCT as a standard tool for caries detection (18).