S.C. Code Ann. § 40-15-310: Subwork authorizations for subcontractors.

If the person receiving a written work authorization from a licensed dentist engages another person to perform some of the dental technological work relative to such work authorization, he shall furnish a written subwork authorization with respect thereto. The subcontractor shall retain the subwork authorization and the issuer thereof shall retain a duplicate copy, attached to the work authorization received from a licensed dentist, for inspection by the board, or its duly authorized agents, on the premises for a period of three years.