In 81.6% of the cases, further imaging was requested after the OPG. Caution should be applied in the interpretation of this number, as the residents’ decision was theoretical and did not imply additional costs or radiation exposure. Nevertheless, it is striking that in the majority of the cases, further imaging was requested. One possible explanation might be the diagnostic difficulty of the chosen cases. This relevant finding indicates a high subjective demand for a CBCT and a lower objective necessity for further imaging after OPG, based on the present cases. However, this conclusion can only be drawn, after performing a CBCT. The onus rests on future scientific endeavours to find means to reduce this discrepancy.

The request for a CBCT was significantly influenced by the residents’ professional background (OS vs ORTH) and gender. Residents in oral surgery, female dentists and residents with limited professional experience as dentists indicated up to six times more often the need for further imaging. When analysing the assessment of impacted canines, Lai et al. observed similarly that oral surgeons requested more often CBCT imaging than orthodontists [19]. This might be explained by the fact that oral surgeons are interested in diagnostic information as well as in information for surgical planning. This takes positional relations with regard to surgical approaches into account, being facilitated by 3D imaging. As mentioned above, orthodontics and oral surgery differ in their judgement on treatability. This offers an obvious explanation for the difference regarding the request for further imaging. Residents in oral surgery, who stated more often that the cases were not treatable with the data obtained solely by OPG, were also the same group who requested significantly more CBCT, and vice versa. It is understandable that less experienced clinicians ask for more CBCT scans, but the interpretation why male dentist would request more CBCT scans is not trivial. Hodges et al. [17] demonstrated that clinicians who own CBCT devices requested more CBCT scans than other dentists. This and other reports suggest that dentist-related variables influence the request for CBCT scans at least as much as case-related factors.