A Silver Spring dentist may have the right to practice polydontics, but he doesn't have the right to advertise such a specialty, according to Maryland's highest court.

The reason, the Court of Appeals ruled in a 6-to-1 decision, is that Dr. Edward M. Barnett invented and trademarked the word "polydontics" and its use would be deceptive and misleading, and could somehow be interpreted as a form of dental specialty that really does not exist.

According to court records, Dr. Barnett began using the phrase in advertisements in 1979, describing it as care for treatment of multiple kinds of dental problems. In one instance, he explicitly described polydontics as "a word we created" to define an individualized approach to dental treatment.

The Maryland State Board of Dental Examiners charged Dr. Barnett late in 1979 with deceptive advertising, using the word for which he had sought U.S. government approval. After a hearing, the dental panel reprimanded him. It was 13 months later that the U.S. Patent and Trademark Office accepted his word "polydontics" as a registered service mark, the equivalent of a trade mark.

On appeal, Dr. Barnett contended that use of his invented word was proper.

In the majority opinion, Judge James F. Couch held that five dental specialties listed in state laws end with "-dontics," with Dr. Barnett's word creating a potential for confusion. Dissenting, Judge Harry A. Cole said any individual reading Dr. Barnett's entire advertisement would recognize that he coined a word to attract clients.