1. A dental impression tray for use in obtaining an impression of at least a part of a dental structure, the dental impression tray comprising: a tray portion adapted to be loaded with impression material, the tray portion being contoured to fit over at least a part of both the upper and lower dental structure of a patient such that an impression can be obtained simultaneously from both the upper and the lower dental structure, the tray portion having a holding section with a first side facing in a first direction and a second side placed opposite the first side and facing in a second direction that is opposite to the first direction, each of the first and second side of the holding section having at least one fastener by means of which the holding section can be locked to a holder having a part with a shape that is complementary in shape to the fasteners on the holding section, the fasteners on both sides of the holding section having the same form such that each side of the holding section can be locked to one and the same holder.