An extra oral dental imaging apparatus for obtaining a radiographic image of a patient, the dental imaging apparatus comprising: - a support frame, - a movable gantry configured to support an x-ray source and an x-ray sensor in correspondence with the x-ray source, the gantry being movable relative to the support frame, - a patient positioning accessory support member (22; 42) configured to support a plurality of patient positioning accessories (24; 28; 30; 32; 40; 50), each patient positioning accessory being of a specific type that is adapted to be used in the dental imaging apparatus for conducting a specific examination on a patient, wherein each patient positioning accessory of the plurality of patient positioning accessories (24; 28; 30; 32; 40; 50) comprises at least one passive identification element that identifies the specific type of patient positioning accessory (24; 28; 30; 32; 40; 50), and - an active identification system configured by construction to cooperate or interact with the at least one passive identification element in order to identify the specific type of patient positioning accessory (24; 28; 30; 32; 40; 50) based on identification information carried or represented by the at least one passive identification element; wherein the active identification system further comprises: - one or several detection elements (100, 102, 106, 108; 234-240; 50) that are configured to cooperate with the at least one passive identification element and generate at least one signal depending on the result of the cooperation, and - a microprocessor (104; 104') configured to: analyze the at least one signal thus generated in order to identify the specific type of patient positioning accessory (24; 28; 30; 32; 40; 50); and compare the identified type of patient positioning accessory (24; 28; 30; 32; 40; 50) with that required for conducting the specific examination to be carried out with the apparatus; wherein the dental imaging apparatus is configured to generate a visual indicator on the patient positioning accessory (24; 28; 30; 32; 40; 50), the visual indicator being in relation with the specific type of patient positioning accessory (24; 28; 30; 32; 40; 50) that has been identified. - a support frame, - a movable gantry configured to support an x-ray source and an x-ray sensor in correspondence with the x-ray source, the gantry being movable relative to the support frame, - a patient positioning accessory support member (22; 42) configured to support a plurality of patient positioning accessories (24; 28; 30; 32; 40; 50), each patient positioning accessory being of a specific type that is adapted to be used in the dental imaging apparatus for conducting a specific examination on a patient, wherein each patient positioning accessory of the plurality of patient positioning accessories (24; 28; 30; 32; 40; 50) comprises at least one passive identification element that identifies the specific type of patient positioning accessory (24; 28; 30; 32; 40; 50), and - an active identification system configured by construction to cooperate or interact with the at least one passive identification element in order to identify the specific type of patient positioning accessory (24; 28; 30; 32; 40; 50) based on identification information carried or represented by the at least one passive identification element; - one or several detection elements (100, 102, 106, 108; 234-240; 50) that are configured to cooperate with the at least one passive identification element and generate at least one signal depending on the result of the cooperation, and - a microprocessor (104; 104') configured to: analyze the at least one signal thus generated in order to identify the specific type of patient positioning accessory (24; 28; 30; 32; 40; 50); and compare the identified type of patient positioning accessory (24; 28; 30; 32; 40; 50) with that required for conducting the specific examination to be carried out with the apparatus; analyze the at least one signal thus generated in order to identify the specific type of patient positioning accessory (24; 28; 30; 32; 40; 50); and compare the identified type of patient positioning accessory (24; 28; 30; 32; 40; 50) with that required for conducting the specific examination to be carried out with the apparatus;