Section 45A. An applicant for limited registration under this section who is eighteen years of age or over and of good moral character who shall furnish the board with satisfactory proof that he has received a diploma from the faculty of a reputable dental college as defined in section forty-six and who shall furnish the board with satisfactory proof that he has been employed as a member of the faculty of a dental college accredited by the Commission on Accreditation of Dental and Dental Auxiliary Educational Programs of the American Dental Association or that he has been appointed a dental intern in a hospital or other institution maintained by the commonwealth or by a county or municipality thereof, or in a hospital or dental infirmary incorporated under the laws of the commonwealth, may upon payment of a fee to be determined annually by the commissioner of administration under the provision of section three B of chapter seven be registered by the board as a limited registrant for one year; provided, however, that practice under any such original or renewal limited registration so issued by the board shall be limited to no longer than five years unless said applicant passes a clinical examination administered by the board or is a full time faculty member. Such limited registration shall entitle said applicant to practice dentistry only in the hospital or other institution designated on his registration and under the direction of a registered dentist employed therein. Limited registration under this section may be revoked at any time by the board and a holder of such a limited registration shall not practice dentistry in a private dental office or private dental clinic; provided, however, that a full time faculty member may participate in, and only in, an intramural group dental practice which is operated, managed and physically located within a nonprofit dental educational or research institution and their affiliated hospitals in which the full time faculty member is employed.