Fourteen residents were recruited for this survey [7 residents in oral surgery (OS) and 7 residents in orthodontics (ORTH), respectively; m = 6, f = 8]. Their characteristics are listed in Table 1. Every resident assessed individually nine separate patient cases, each containing a distinct dentoalveolar pathology, as defined in the study planning process (Table 2).

For each patient case, an OPG, a CBCT and a printed 3D model were shown in sequential order to each resident. Each resident assessed each patient case and each type of imaging modality (OPG, CBCT, 3D model) on the basis of a questionnaire customised for this study. The questionnaire comprised diagnostic items and questions relating to diagnosis and patient management (treatability). The correct diagnosis of each case was determined by two independent and experienced senior consultants prior to the residents’ assessment.

Medical records of the Clinic of Cranio-Maxillofacial and Oral Surgery and the Clinic of Orthodontics and Paediatric Dentistry of the University of Zurich, Switzerland were searched for patient cases with the following inclusion criteria:

Treatment indication due to supernumerary, displaced or retained teeth, bone or teeth resorptions, or odontomas

Availability of an OPG and a CBCT (Accuitomo 170)

Patient age between 6 and 30 years

Time lapse between OPG and CBCT no more than 6 months, no dental treatment performed between the imaging

Informed consent for further use of patient data for clinical research given by the patient and wherever necessary by the parents/legal guardians

Every resident assessed the cases separately in the presence of the same supervisor, in order to ascertain identical settings and equal instructions to the viewer software (Morita I-Dixel). Uncertainties were clarified prior to completing the questionnaires. Patient cases were anonymised and presented to every resident in the same order.

The residents had to answer the questions under the following standardised conditions:

Time available: 1 h 15 min

Each resident assessed three images per patient in the following sequence: OPG CBCT, 3D model. For each image modality, a questionnaire had to be filled out