1. A kit for making a dental impression and holding the impression for a scanning operation, the kit comprising: a dental impression tray comprising a tray portion comprising a U-shaped impression section adapted to be loaded with impression material, the tray portion being contoured to fit over at least a part of both an upper dental structure and a lower dental structure to simultaneously obtain an impression of the part of the upper dental structure and the part of the lower dental structure, the tray portion comprising a holding section projecting from a curved surface of the U-shaped impression section, the holding section comprising a first side facing in a first direction and a second side opposite the first side and facing in a second direction that is opposite to the first direction, each of the first side of the holding section and the second side of the holding section comprising a plurality of fasteners, wherein each of the plurality of fasteners is in the form of a hole or a recess; a holder comprising an alignment part configured to secure the dental impression tray stationary during scanning of the impression of the part of the upper dental structure in a vertical and lateral configuration and during scanning of the impression of the part of the lower dental structure in the same vertical and lateral configuration when the dental impression tray is turned 180°, the holder comprising a plurality of projections or pegs having a shape that is complementary in shape to the fasteners of the first side of the holding section and the fasteners of the second side of the holding section, wherein the fasteners of the first side of the holding section and the fasteners of the second side of the holding section are configured to lock the holding section to the alignment part of the holder, the fasteners of the first side of the holding section and the fasteners of the second side of the holding section each having a form lockable to the holder; and a handle securable to the tray portion and removable from the tray portion, the handle comprising a plurality of fastening elements, wherein each of the plurality of fastening elements is in the form of a projection or a peg, the plurality of fastening elements being complementary in shape to the fasteners of the first side of the holding section and the fasteners of the second side of the holding section, the handle manipulable by a user to align the tray portion in a patient's mouth with eyes of the patient, wherein the holder is designed to cooperate with the same fasteners of the holding section of the dental impression tray as the handle, and wherein the handle has a different shape than the holder.