4.4 Prohibited Functions, Unauthorized Duties, and Auxiliary Delegation (BPC § 1908(b))

Prohibited Functions, Unauthorized Duties, and Auxiliary Delegation (BPC § 1908(b))

The Five Explicit Statutory Prohibitions: BPC § 1908(b)

The California Dental Practice Act not only authorizes specific preventative and therapeutic functions but also explicitly delineates procedures that lie strictly outside the scope of dental hygiene. Business and Professions Code Section 1908(b) establishes five explicit statutory prohibitions:

"The practice of dental hygiene does not include any of the following procedures:

1. Diagnosis and comprehensive treatment planning.
2. Placing, condensing, carving, or removal of permanent restorations.
3. Surgery or cutting on hard and soft tissue including, but not limited to, the removal of teeth and the cutting and suturing of soft tissue.
4. Prescribing medication.
5. Administering local or general anesthesia or oral or parenteral conscious sedation, except for the administration of nitrous oxide and oxygen, whether administered alone or in combination with each other, or local anesthesia pursuant to Section 1909."

These statutory boundaries are absolute. Engaging in any of these prohibited functions violates both the Dental Hygiene Practice Act (BPC §§ 1900–1967.4) and the Dental Practice Act governing dentists (BPC § 1600 et seq.), constituting unauthorized practice of dentistry and unprofessional conduct.

Assessment vs. Diagnosis: Navigating the Critical Clinical Boundary

One of the most frequently tested areas on the California Dental Hygiene Jurisprudence Examination is the precise legal distinction between a dental hygiene assessment and a dental diagnosis.

Authorized Dental Hygiene Assessment

Under BPC § 1908(a), an RDH is licensed to perform comprehensive dental hygiene assessments. This includes:

• Collecting subjective and objective clinical data (medical history review, vital signs);
• Performing extraoral and intraoral soft tissue examinations to identify abnormalities;
• Recording periodontal findings, including six-point probing depths, clinical attachment loss (CAL), recession, bleeding on probing (BOP), suppuration, furcation involvement, and tooth mobility;
• Assessing plaque and calculus indices;
• Conducting caries risk assessments (CAMBRA) and oral cancer screenings;
• Formulating a dental hygiene diagnosis—defined as the identification of an existing or potential oral health problem that a dental hygienist is educationally qualified and licensed to treat (e.g., biofilm-induced gingivitis, stage II periodontitis related to subgingival calculus, or dentinal hypersensitivity);
• Formulating a dental hygiene care plan specifying hygiene interventions, treatment intervals, and home care strategies.

Prohibited Dental Diagnosis and Treatment Planning

Under BPC § 1908(b)(1), an RDH is strictly prohibited from making a definitive dental or medical diagnosis or approving a comprehensive dental treatment plan:

• An RDH cannot diagnose dental caries from clinical observation or radiographs;
• An RDH cannot diagnose periapical abscesses, cysts, or bony pathologies;
• An RDH cannot prescribe endodontic, restorative, orthodontic, or prosthodontic therapies;
• An RDH cannot present a final treatment plan to a patient without prior dentist clinical evaluation and approval.

Clinical Protocol: When an RDH detects clinical or radiographic signs of pathology (such as interproximal radiolucencies suggestive of caries or a suspected periapical lesion), the hygienist must document the objective findings in the chart, inform the patient that areas requiring the dentist's evaluation have been noted, and present the findings directly to the dentist. The dentist must perform an independent clinical examination, establish the formal diagnosis, and authorize the treatment plan.

Restorative and Surgical Boundary Lines

Restorative Prohibitions

Under BPC § 1908(b)(2), standard RDHs are statutorily barred from:

• Placing, condensing, carving, or contouring permanent restorative materials (amalgam, composite resin, gold, glass ionomer permanent restorations);
• Removing permanent restorations or excavating carious dentin;
• Preparing tooth structure or cavomargins using rotary handpieces.

Statutory Distinction: An RDH may apply temporary sedative dressings (an RDA duty under BPC § 1907) or place pit and fissure sealants, but cannot place permanent restorations. Only Registered Dental Hygienists in Extended Functions (RDHEFs) or Registered Dental Assistants in Extended Functions (RDAEFs) who hold specialized post-graduate licensure under BPC § 1913 may pack and carve permanent restorations under direct dentist supervision.

Surgical Prohibitions

Under BPC § 1908(b)(3), cutting hard or soft tissue is strictly proscribed. RDHs cannot:

• Make incisions using scalpels, surgical blades, or electrosurgical units;
• Perform surgical flap reflection, excisional gingivectomy, or frenectomies;
• Extract erupted or impacted teeth;
• Place or tie surgical sutures.

The sole statutory exception for soft tissue instrumentation is closed soft tissue curettage under BPC § 1909, which involves removing diseased sulcular pocket epithelium without surgical flap elevation or incision.

Prescriptive Authority and Drug Limitations

Unlike advanced practice registered nurses or physicians, California dental hygienists possess no independent prescriptive authority:

• Prohibited: Writing or calling in prescriptions for systemic antibiotics (e.g., amoxicillin, clindamycin), narcotic or non-narcotic analgesics, anxiolytics, or anti-inflammatory drugs. Calling in a prescription to a pharmacy without a dentist's direct, documented order is a criminal violation.
• Permitted: Administering topical preventative agents (fluoride varnishes, silver diamine fluoride) and subgingival chemotherapeutic agents (chlorhexidine irrigation, Arestin microspheres) pursuant to dental protocol or direct authorization under BPC § 1910.

Auxiliary Delegation and Aiding and Abetting Unlicensed Practice (BPC § 1950.5(b))

Dental hygienists frequently work alongside Dental Assistants (DAs) and Registered Dental Assistants (RDAs). An RDH must understand the legal parameters governing auxiliary delegation:

• Lawful Delegation: An RDH may direct a Dental Assistant to perform basic supportive services authorized under BPC § 1750, such as operating oral suction, retracting oral tissues, taking preliminary study model impressions, or operating dental radiography equipment (if the DA holds a Board radiation safety certificate).
• Unlawful Delegation: An RDH cannot delegate duties requiring professional licensure to an unqualified assistant. An RDH cannot permit an unlicensed DA to perform coronal polishing, apply pit and fissure sealants, or perform periodontal scaling.
• Aiding and Abetting Unlicensed Practice: Under Business and Professions Code Section 1950.5(b), aiding or abetting an unlicensed person to practice dentistry or dental hygiene constitutes unprofessional conduct. A hygienist who delegates scaling to an assistant, or who allows an assistant to perform licensed duties under their watch, faces disciplinary action by the DHBC, including license suspension or revocation.

Real-World Boundary Traps and Employer Pressure

Jurisprudence exams frequently present scenarios where an employer dentist pressures an auxiliary to exceed their statutory scope:

1. Employer Request to "Drill Out Shallow Caries": An employer dentist running behind asks an RDH to use a slow-speed handpiece to clean out shallow pit decay. Legal Reality: The hygienist must refuse. Cutting hard tissue is excluded from the practice of dental hygiene by BPC § 1908(b)(3), and doing it anyway is unprofessional conduct under BPC § 1954 and unlicensed practice of dentistry under the Dental Practice Act. BPC § 1960 makes practicing dental hygiene without a valid license a misdemeanor on a first offense, punishable by a fine of $200 to $3,000 or up to six months in county jail or both, and a felony on a second or subsequent offense; BPC § 1961 raises the exposure to up to one year in county jail where the unlicensed practice occurs under circumstances causing a risk of bodily harm, serious illness, or death. An employer dentist's instruction provides zero legal immunity, and BPC § 1950.5(c) makes aiding or abetting a licensed person to practice unlawfully unprofessional conduct for the dentist as well.
2. Calling in Antibiotics for a Swollen Patient: A dentist text-messages an RDH: "Call in amoxicillin 500mg for Mrs. Jones; I'm stuck on the freeway." Legal Reality: An RDH cannot transmit prescription orders unless explicitly authorized under state telephonic prescription transmission rules where the dentist has directly prescribed the drug. If the dentist has not examined the patient or written the order, transmitting a prescription constitutes unlawful prescribing.
3. Presenting Treatment to Patients: An RDH tells a patient: "You have three cavities on your upper molars that need composite fillings, and I'll schedule you for that." Legal Reality: This violates BPC § 1908(b)(1). The hygienist must state: "I've noted some suspicious areas on your radiographs that I will have the dentist evaluate during your clinical examination."

Clinical Boundary Matrix: Permitted vs. Prohibited Procedures for California RDHs