The board shall grant without examination a certificate of registration and license to a dental hygienist who has been licensed in another state for at least two consecutive years immediately preceding his application to practice in Missouri if the board is satisfied by proof adduced by the applicant that his qualifications are at least equivalent to the requirements for initial registration as a dental hygienist in Missouri under the provisions of this chapter; provided that the board may by rule require an applicant under this section to take any examination over Missouri laws given to dental hygienist initially seeking licensure under section 332.251 and to take a practical examination if his licensure in any state was ever denied, revoked or suspended for incompetency or inability to practice in a safe manner, or if he has failed any practical examination given as a prerequisite to licensure as a dental hygienist in any state. Any such dental hygienist applying to be so registered and licensed shall accompany his application with a fee not greater than the dental hygienist examination and license fees and if registered and licensed shall renew his license as provided in section 332.261.