Practice Management Information Corp. v. American Medical Association, No. Any original literary work may be copyrighted. Term papers by college sophomores are as much within the domain of copyright as Saul Bellow's latest novel. Scholarship that explicates important facts about the universe likewise is well within this domain. Facts do not supply their own principles of organization.
Classification is a creative endeavor.
Dental procedures could be classified by complexity, or by the tools necessary to perform them, or by the parts of the mouth involved, or by the anesthesia employed, or in any of a dozen different ways. There can be multiple, and equally original, biographies of the same person's life, and multiple original taxonomies of a field of knowledge. Creativity marks the expression even after the fundamental scheme has been devised. This is clear enough for the long description of each procedure in the ADA's Code. The long description is part of the copyrighted work, and original long descriptions make the work as a whole copyrightable.