Examinations for licensing as specialists are held annually or as the board may determine. The examinations must be theoretical and practical. The theoretical examinations shall include subjects represented in that recognized special area of dentistry in which the applicant desires to specialize. The examination must be given either orally or in writing, or by requiring a practical demonstration of the applicant’s skill, or by any combination of the methods as the board may require. The fee for the examinations and special license is prescribed in the regulations of the board. Any applicant who fails to pass the examination may apply for a subsequent examination, in which case he shall pay to the secretary a fee prescribed in the regulations of the board for each subsequent examination. A diplomate of a national certifying board recognized by the American Dental Association may be granted a specialty license without examination by the board after satisfactory completion of the application and submission of fees applicable to other applicants. A dentist now holding a valid South Carolina specialty license is not required to be reexamined for that specialty license after April 13, 1968.