Ninety-Five Miles From the Dentist: Supervision and Scope at a Rural Clinic
The only dental clinic in a rural New Mexico county is staffed on Wednesdays by a licensed dental hygienist who holds a local anesthesia permit, an expanded-function dental assistant (EFDA), and a licensed dental therapist. The supervising dentist reviews the schedule on Monday, is reachable by telephone, and is not on site. On a Wednesday: (1) the hygienist wants to administer 2% lidocaine with 1:100,000 epinephrine before scaling a 62-year-old patient with controlled hypertension; (2) the EFDA wants to place a temporary crown on a symptomatic tooth because the patient cannot return for two weeks; and (3) the dental therapist wants to extract a mobile, erupted permanent maxillary premolar and prescribe amoxicillin. The clinic's collaborative agreement and standing orders say nothing about the premolar or the temporary crown. The hygienist asks the dentist by phone for verbal approval.
1. Analyze whether the hygienist may administer local anesthesia with the dentist off site.
Read the worked answer
The starting point is not the hygienist's competence but the supervision level the Board attaches to the local anesthesia permit. New Mexico rules define supervision categories - commonly direct (dentist physically present and available), indirect (dentist on site but not in the room), and general (dentist not on site) - and the permit rule specifies which applies to each procedure.
Application. A phone call is not physical presence. If the rule requires direct supervision for local anesthesia by a hygienist, the procedure cannot go forward Wednesday, and verbal approval does not cure the defect. If the rule permits a lesser supervision level for a hygienist with the permit, the clinic must still satisfy any conditions: a current written protocol, emergency equipment and training, medical clearance for the patient's hypertension, and documentation of the supervising dentist's authorization.
Practical step. Before the appointment, the clinic should pull the rule and the permit conditions and, if uncertain, reschedule or refer. Chart the supervision determination and the patient's blood pressure. Telephone authorization should be documented in writing, including time and content.
2. May the EFDA place the temporary crown? Explain how the Board analyzes expanded-function scope.
Read the worked answer
Expanded-function scope is defined by three layers: the Dental Practice Act, the Board's EFDA rules, and the written delegation or standing order from the supervising dentist. A procedure is permissible only if all three permit it. The EFDA's certificate does not create authority by itself.
Temporary crown. Placing and cementing a temporary crown involves tooth preparation, occlusion, and margin fit, and it may involve adjusting a tooth that has been prepared. Some states allow certain EFDAs to fabricate and cement provisionals under direct or indirect supervision; others do not. The correct answer depends on the current EFDA rule and the dentist's written delegation.
Silence is not permission. Because the standing orders say nothing, the EFDA should not proceed. The dentist should either come to the clinic, direct the patient to a facility where the tooth can be managed, or issue a specific written order if the rule allows it. The EFDA should document the symptomatic tooth, the call to the dentist, and the plan. The Board's concern is unauthorized practice, not whether the temporary would have helped.
3. May the dental therapist extract the permanent premolar and prescribe amoxicillin?
Read the worked answer
Dental therapist scope is set by the Dental Practice Act and Board rules and is further limited by the collaborative practice agreement. The therapist must be able to point to express authority for each act.
Extraction. Many dental therapist models authorize extraction of primary teeth and certain periodontally involved teeth, but permanent-tooth extraction is typically narrower or requires additional training and a specific protocol. A mobile permanent premolar may be periodontally involved or may be mobile for another reason; without radiographs and a diagnosis, the cause is unknown. Extraction of a permanent tooth is a surgical procedure, and the therapist may not infer authority from general restorative scope. If the rule and collaborative agreement do not expressly authorize it, the therapist must refer.
Prescribing. Prescribing authority is separate from procedure authority. The therapist must check whether the collaborative agreement grants prescriptive authority, whether a formulary applies, and whether amoxicillin is appropriate given the diagnosis. Antibiotics are not a substitute for source control, and prescribing without a diagnosis raises both scope and standard-of-care issues.
Conclusion. Absent express authority, the therapist should not extract or prescribe, and should arrange referral or dentist attendance.