Must Article 140(a) and (b) of the 2006 VAT Directive be interpreted as meaning that the exemption from VAT for which that provision provides does not apply to the intra-Community acquisition of dental prostheses? If the answer is no, is the application of the exemption subject to the condition that the dental prostheses are supplied from abroad by a dentist and/or dental technician to a dentist or dental technician?