Every dentist who operates a dental office in the state of Washington must write a valid prescription to the dental laboratory or dental technician with whom he/she intends to place an order for the making, repairing, altering or supplying of artificial restorations, substitutes or appliances to be worn in the human mouth. A separate prescription must be submitted to the dental laboratory or dental technician for each patient's requirements. To be valid, such prescriptions must be written in duplicate and contain the date, the name and address of the dental laboratory or the dental technician, the name and address of the patient, description of the basic work to be done, the signature of the dentist serving the patient for whom the work is being done and the dentist's license certificate number. The original prescription shall be referred to the dental laboratory or the dental technician and the carbon copy shall be retained for three years, by the dentist, in an orderly, accessible file and shall be readily available for inspection by the secretary or his/her authorized representative.