Maryland Code, Health Occupations § 4-404

(a)(1) The dentist who signs a work authorization shall:

(2) The dental laboratory named in the original work authorization shall:

(b)(1) The person who keeps or receives the original or copy of a work authorization or subcontracted work authorization shall keep it for at least 1 year.

(2) If a subcontracted work authorization is issued, the dental laboratory named in the original work authorization shall attach the original work authorization form to the copy of the subcontracted work authorization form and keep the two together in the files of the dental laboratory for at least 1 year.