Cal. Bus. & Prof. Code § 1626.5

In addition to the exemptions set forth in Section 1626, the operations by bona fide students of registered dental assisting, registered dental assisting in extended functions, and registered dental hygiene in extended functions in the clinical departments or the laboratory of an educational program or school approved by the board, including operations by unlicensed students while engaged in clinical externship programs that have been approved by an approved educational program or school, and that are under the general programmatic and academic supervision of that educational program or school, are exempt from the operation of this chapter.