Mo. Rev. Stat. § 332.201
The board may not issue any temporary certificates of registration or licenses to practice dentistry in Missouri; except, upon the request and recommendation of the department of health and senior services, the department of mental health, or the department of corrections and human resources, the board shall issue a letter authorizing an uncertificated and unlicensed graduate of an accredited dental school to practice dentistry if the board determines that the recommended person is qualified to take the dental examination and if this person is employed by an institution operated by one of the aforenamed agencies the letter shall be effective for such period of time as may be authorized by the board, but any such authorization issued by the board shall in no event extend beyond the date that the results of the board's dental examination or examinations next following the date of the authorization are announced.
§ 332.201, RSMo