4.1 RDH Allowable Duties Under California Law (BPC §§ 1907, 1908, 1910)

RDH Allowable Duties Under California Law (BPC §§ 1907, 1908, 1910)

Statutory Foundation: Defining Dental Hygiene Practice (BPC § 1908)

The California Dental Practice Act, codified within Division 2, Chapter 4, Article 9 of the California Business and Professions Code (BPC §§ 1900–1967.4), strictly governs the clinical scope, educational standards, and regulatory obligations of Registered Dental Hygienists (RDHs). Foundational to this statutory framework is Business and Professions Code Section 1908(a), which formally defines the legal practice of dental hygiene:

"The practice of dental hygiene includes dental hygiene assessment and development, planning, and implementation of a dental hygiene care plan. It also includes oral health education, counseling, and health screenings."

This statutory definition codifies the contemporary dental hygiene process of care. An RDH does not merely execute technical mechanical tasks; rather, the practitioner operates as a licensed primary preventive oral healthcare professional. The dental hygiene assessment involves the systematic collection and analysis of clinical, comprehensive periodontal, and diagnostic data. This includes measuring and recording periodontal probing depths, assessing clinical attachment loss (CAL), evaluating bleeding on probing (BOP), identifying furcation involvement, assessing tooth mobility, charting oral conditions, performing extraoral and intraoral soft tissue screenings, and assessing individual caries risk.

Following comprehensive assessment, the RDH formulates a customized dental hygiene care plan designed to arrest active disease, restore periodontal health, and maintain long-term oral function. Implementation encompasses mechanical therapy, therapeutic chemotherapeutic delivery, patient education, and nutritional counseling. It is essential to recognize the statutory distinction between a dental hygiene assessment and a dental diagnosis. While an RDH identifies periodontal conditions and formulates a dental hygiene treatment plan, BPC § 1908(b)(1) explicitly reserves the definitive diagnosis of dental disease and the overall comprehensive dental treatment plan to the licensed dentist.

Core Clinical Mechanical Interventions (BPC § 1910)

Business and Professions Code Section 1910 establishes the core mechanical clinical interventions that an RDH is licensed to perform. These procedures constitute the foundation of preventative and therapeutic periodontal practice:

1. Oral Prophylaxis: Defined by statute in BPC § 1902(e) as "preventive and therapeutic dental procedures that include bacterial debridements with complete removal, supra and subgingivally, of calculus, soft deposits, plaque, and stains, and the smoothing of tooth surfaces," with the objective of creating an environment in which the patient can maintain healthy hard and soft tissues. (The parallel Dental Board definition at 16 CCR § 1067(g) describes the complete removal of explorer-detectable calculus, soft deposits, plaque, and stains and the smoothing of unattached tooth surfaces.) Note the statutory contrast with coronal polishing, which 16 CCR § 1067(h) limits to removing plaque and stain from exposed tooth surfaces with a rotary instrument and polishing agent — a narrower RDA-level duty, not a prophylaxis.
2. Supragingival and Subgingival Scaling: The instrumentation of coronal and radicular tooth surfaces to dislodge calcified accretions, bacterial bioburden, and microbial endotoxins. Subgingival scaling extends beneath the gingival margin into pocket depths to eliminate submarginal calculus.
3. Periodontal Root Planing (SRP): A definitive therapeutic treatment designed to instrument diseased cementum and dentin that is rough, calculus-encrusted, or permeated with toxic byproducts and microorganisms. Root planing establishes a smooth, biologically compatible root surface that facilitates tissue healing, reduces periodontal pocket depths, and promotes the biological reattachment of the junctional epithelium.

Preventive, Therapeutic, and Subgingival Chemotherapeutic Agents

Under BPC § 1910(b), an RDH is authorized to apply topical, therapeutic, and subgingival agents for the control of dental caries and periodontal disease. The contemporary clinical armamentarium includes both preventative and chemotherapeutic modalities:

• Topical Fluoride Agents: RDHs are authorized to apply topical fluoride solutions, foams, gels, and varnishes (such as 5% sodium fluoride varnish) to prevent enamel demineralization, enhance remineralization, and treat dentinal hypersensitivity.
• Silver Diamine Fluoride (SDF): As an advanced therapeutic agent (typically 38% SDF), silver diamine fluoride is utilized to arrest active cavitated carious lesions and treat severe hypersensitivity. California law permits RDHs to apply SDF under general supervision pursuant to established dental protocols and following appropriate informed consent regarding potential dark staining of arrested lesions.
• Subgingival Chemotherapeutic Irrigation: Delivery of antimicrobial agents directly into periodontal pockets using blunt-tipped cannulas or specialized ultrasonic inserts. Agents such as 0.12% chlorhexidine gluconate or povidone-iodine provide immediate reduction of subgingival microflora.
• Locally Administered Sustained-Release Antimicrobials: RDHs are authorized to place subgingival chemotherapeutic delivery systems into diseased periodontal pockets (typically pockets ≥ 5 mm demonstrating persistent bleeding on probing). These therapeutic agents include minocycline hydrochloride microspheres (Arestin), doxycycline hyclate liquid polymer (Atridox), and chlorhexidine gluconate biodegradable chips (PerioChip). These agents release therapeutic antimicrobial concentrations over 7 to 14 days without inducing systemic antibiotic resistance.

Registered Dental Assistant (RDA) Duties Authorized for RDHs (BPC § 1907)

A pivotal provision of the Dental Practice Act is Business and Professions Code Section 1907, which establishes an expansive statutory bridge between auxiliary categories:

"The following functions may be performed by a registered dental hygienist, in addition to those authorized pursuant to Sections 1908 to 1914, inclusive: (a) All functions that may be performed by a registered dental assistant."

Under BPC § 1907, an RDH is automatically authorized to perform every allowable duty designated for a Registered Dental Assistant (RDA) without holding a separate RDA license. When performing RDA duties, the RDH must adhere to the supervision level statutorily prescribed for that specific RDA function. Key RDA duties frequently performed by RDHs include:

• Coronal Polishing: Mechanical polishing of the clinical crowns of teeth to remove extrinsic stains and plaque.
• Pit and Fissure Sealants: Etching enamel and applying preventive resin or glass ionomer sealants to occlusal pits and anatomical grooves.
• Diagnostic Radiography: Exposing intraoral (periapical, bitewing, occlusal) and extraoral (panoramic, cephalometric, cone-beam CT) radiographs.
• Isolation and Matrix Placement: Placing and removing rubber dams, matrix bands, and wedges prior to operative procedures.
• Diagnostic Impressions: Taking preliminary impressions for diagnostic study models, bleaching trays, and athletic mouthguards using elastomeric materials, alginate, or digital intraoral optical scanners.
• Cement Removal: Removing excess supragingival temporary and permanent cement from coronal surfaces and restorations using hand instruments.
• Periodontal Dressings: Placing and removing post-surgical periodontal dressings.

Additional Authorized Duties: Radiographic Decision-Making and Interim Therapeutic Restorations (BPC § 1910.5)

BPC § 1910.5, most recently amended by SB 1526 (Stats. 2024, Ch. 497, effective January 1, 2025), adds two duties beyond the § 1910 list:

1. Radiographic decision-making. An RDH may determine which radiographs to perform on a patient who has not yet received an initial examination by the supervising dentist, for the specific purpose of letting the dentist make a diagnosis and treatment plan. The hygienist must follow protocols established by the supervising dentist, and the duty applies in only two settings: (A) a dental office setting, and (B) a public health setting using telehealth, as defined by BPC § 2290.5, for communication with the supervising dentist — including schools, Head Start and preschool programs, and community clinics.
2. Interim therapeutic restorations (ITRs). An RDH may place a protective restoration defined as a direct provisional restoration that stabilizes a tooth until a dentist diagnoses the need for further definitive treatment. An ITR consists of removing soft material using only hand instrumentation — no rotary instrumentation — and then placing an adhesive restorative material. The statute notes that local anesthesia is not necessary for ITR placement. ITRs may be placed only (A) in a dental office or a telehealth-supported public health setting, and (B) after the dentist's diagnosis, treatment plan, and instruction to perform the procedure.

Both duties require completion of a program or board-approved course covering those functions (BPC § 1910.5(b)), with curriculum requirements adopted at 16 CCR § 1109. Do not confuse an ITR with a permanent restoration: BPC § 1908(b)(2) still excludes placing, condensing, carving, or removing permanent restorations from the practice of dental hygiene.

Fluoride Varnish Without Supervision (BPC § 1911.5)

BPC § 1911.5, added by SB 653 (Stats. 2020, Ch. 130, effective January 1, 2021), states that notwithstanding Section 1912, a registered dental hygienist may provide fluoride varnish without supervision. This is the single broadest unsupervised clinical authority an ordinary RDH holds: it is not limited to public health programs, schools, or sponsored events the way BPC § 1911(c) fluoride and sealant authority is. Exam items frequently test the contrast — varnish anywhere without supervision; gels, foams, rinses, and sealants unsupervised only inside a qualifying § 1911(c) program.

In-Office and Take-Home Tooth Whitening (BPC § 1910(c)-(d))

Under BPC § 1910(c) and (d), California law authorizes RDHs to perform vital tooth bleaching and whitening procedures. This scope encompasses:

1. Preliminary Impressions and Tray Fabrication: Taking diagnostic impressions, pouring casts, fabricating custom vacuum-formed bleaching trays, and delivering bleaching materials (such as carbamide peroxide or hydrogen peroxide gels) with comprehensive patient instructions.
2. In-Office Non-Laser Whitening: Applying chemical whitening agents directly to tooth surfaces and activating them using non-laser, light-curing devices (e.g., LED or halogen curing lights).
3. Laser Whitening Prohibition: The statute explicitly restricts RDHs to non-laser light-curing whitening agents. Standard RDHs are strictly prohibited from operating dental lasers for tooth whitening or surgical procedures, as hard- and soft-tissue lasers remain restricted to dentists or specialized certifications where explicitly authorized by board regulation.

Comprehensive Inventory of RDH Allowable Duties & BPC References