The board may either refuse to issue or renew or may suspend or revoke any certificate of registration or approval for any one or a combination of the following causes: (1) Conviction of a felony shown by a certified copy of the record of the court of conviction; (2) gross malpractice or gross incompetency; (3) continued practice by a person knowingly having an infectious or contagious disease; (4) advertising by means of knowingly false or deceptive statements or in violation of section 71-223.02; (5) advertising, practicing, or attempting to practice under a trade name or any name other than one's own; (6) habitual drunkenness or habitual addiction to the use of morphine, cocaine, or other habit-forming drugs; (7) immoral or unprofessional conduct; (8) violation of any of the provisions of sections 71-201 to 71-237 or of any valid regulation promulgated by the board pertaining to service charges, sanitation, and the elimination of unfair practices; and (9) any check presented to the board as a fee for either an original license or renewal license or for examination for license or any other fee authorized in sections 71-201 to 71-237 which is returned to the State Treasurer unpaid.