§448-13  Certificate, evidence.  All certificates of license issued by the board of dentistry shall be signed by the chairperson, sealed, and shall be presumptive evidence of the right of the holder to practice dentistry.  No person shall practice dentistry without first having procured such a certificate, except as provided in this chapter.  Any person practicing dentistry and not having at the time a valid and uncanceled license shall be guilty of a failure to comply with this chapter and shall be punished as in this chapter provided.