A dentist may use the services of a dental assistant to perform the following intraoral duties under the direct supervision of a dentist: Rinsing and aspiration of the oral cavity; Retraction of the lips, cheek, tongue, and flaps; Placement and removal of materials for the isolation of the dentition, provided that the material is not retained by the dentition; Instructing on oral hygiene; Performing intraoral photography; Taking impressions for study models or diagnostic casts; Constructing athletic mouth guards on models; Applying topical anesthesia; Curing by the use of halogen light; Checking for loose bands; and Any other duty approved by the Board.