. "A person shall be deemed to be practicing dentistry if he holds himself out as being able to diagnose, treat, operate or prescribe for any disease, pain, injury, deficiency, deformity or other condition of the human teeth, alveolar process, gums or jaws, and associated parts, intraorally or extraorally, or if he either offers or undertakes by any method to diagnose, treat, operate or prescribe for" . . . . .