In general, the invention relates to techniques for registering a three-dimensional coordinate system of a physical model of a patient’s tooth structure to a 3D coordinate system of a virtual model of the same tooth structure. The needle advancing apparatus advances suture through the tissue wall. There is disclosed a RFID interrogator andor method of interrogating comprising an antenna, when activated, being adapted to radiate an interrogation signal in a first area, means adapted to shift the antenna within a second area, the second area being larger than the first area. The data lines are coupled to respective inputs of a DC sense amplifier, one of which is provided for each array. The condenser is provided in one portion of the outer periphery of a machine room in a lower portion of the refrigerator while the machine is closed in other portions of the outer periphery so that air flow tofrom the machine room is enabled only through the condenser to enhance cooling efficient and thus condensing efficient.