Every person practicing dentistry in this Commonwealth shall display his license in his office in plain view of patients. Any person practicing dentistry without having his license on display shall be subject to disciplinary action by the Board.

The provisions of this section shall not apply to any dentist while he is serving as a volunteer providing dental services in an underserved area of the Commonwealth under the auspices of a Virginia charitable corporation granted tax-exempt status under § 501(c)(3) of the Internal Revenue Code and operating as a clinic for the indigent and uninsured that is organized for the delivery of primary health care services.