Section 52C. No person engaged in the business of supplying, constructing, reproducing, relining, repairing, adding or directing the application of any substance of a permanent nature to dentures, bridges, appliances or other structures to be worn as substitutes for natural teeth shall advertise his services, technique or materials to the general public by means of advertisements in public newspapers, magazines or by radio or television display advertisements excepting, advertisements in professional or trade papers, trade journals, trade directories, trade periodicals, trade magazines, and in the public telephone directories; nor shall any person so engaged in any way directly solicit the patronage of the general public for any dental services, dental materials or dental appliances.