A licensed dentist may delegate to a competent dental hygienist those procedures over which the dentist exercises full responsibility, except those procedures that require professional judgment and skill such as diagnosis and treatment planning, the cutting of hard or soft tissue, or any intraoral procedure which would lead to the fabrication of any appliance that, when worn by the patient, would come in direct contact with hard or soft tissue and which could result in tissue irritation or injury. The board of dental examiners may adopt rules governing the scope of practice of dental hygienists.