Any licensed dentist, public institution, or school authority may employ any licensed dental hygienist, whose activities are confined to performing those services and procedures that the licensed dental hygienist has been educated to perform, and which services and procedures are, from time to time, specifically authorized by rules and regulations adopted by the board of examiners in dentistry. Nothing in this section is construed to authorize a licensed dental hygienist to perform the following: diagnosis and treatment planning, surgical procedures on hard or soft tissue, prescribe medication, or administer general anesthesia or injectables other than oral local anesthesia.