RDA Exam Study Guide — Dental Assistant License Prep 2026 June

RDA vs CDA: Key Differences

The Registered Dental Assistant (RDA) and the Certified Dental Assistant (CDA) are two distinct credentials that are often confused. Understanding the difference is essential before you begin your application process.

The CDA is a national, voluntary credential awarded by the Dental Assisting National Board (DANB). It is recognized across all 50 states and signals a high standard of professional competence. To earn the CDA, candidates must pass the Infection Control (ICE), Radiation Health and Safety (RHS), and General Chairside (GC) component exams. The CDA does not replace state licensure where it is required.

The RDA, on the other hand, is a state-issued license that legally authorizes a dental assistant to perform specific expanded duties within that state. Only certain states use the RDA title — most notably California, which has one of the most well-defined RDA programs in the country. Other states may use titles such as Expanded Function Dental Assistant (EFDA), Qualified Dental Assistant (QDA), or simply Licensed Dental Assistant (LDA).

Key differences at a glance:

• Scope: RDA is a legal license; CDA is a professional certification
• Authority: RDA granted by state dental board; CDA granted by DANB (national body)
• Portability: CDA transfers across states; RDA does not — you must apply in each state
• Expanded duties: RDA often allows procedures like coronal polishing, applying sealants, and taking impressions; CDA does not expand scope alone

Many dental assistants hold both credentials — the CDA for national recognition and the RDA for state authorization to perform expanded functions. For a comparison with other allied health certifications, see our guide on CCMA certification and EMT certification to understand how dental assisting licensure fits within the broader healthcare credentialing landscape.

State Requirements Overview

Because RDA is a state-level designation, requirements vary considerably. The three states with the largest populations of registered dental assistants — California, Texas, and New York — each have distinct pathways.

California has the most structured RDA program. The California Dental Board requires candidates to complete a state-approved RDA program or equivalent work experience (3,500 hours over at least 3 years under a licensed dentist), pass the California RDA Written Exam and the RDA Law and Ethics Exam, and pass a clinical examination. California also has a separate Registered Dental Assistant in Extended Functions (RDAEF) designation for advanced procedures.

Texas does not use the RDA title in the same way. The Texas State Board of Dental Examiners (TSBDE) issues licenses for Dental Assistants performing radiographic procedures, and expanded function duties require a separate certificate. Many Texas dental assistants pursue the DANB CDA as their primary credential.

New York does not currently require dental assistants to hold a state license for most chairside duties, but dental radiography requires a certificate of qualification. New York dental assistants frequently pursue DANB certification to demonstrate competency.

Other notable states with formal RDA or equivalent licensure include Oregon, Minnesota, and Washington, each with their own exam and education requirements. Always verify current requirements directly with your state dental board, as rules are updated periodically.

RDA Exam Format: State Board vs DANB

Depending on your state, you will take either a state-specific board exam or qualify using DANB component exams. Some states accept both.

State Board Exams are developed and administered by the individual state dental board or a contracted testing organization. California's RDA Written Exam, for example, covers topics including chairside assisting, infection and hazard control, radiography, materials and pharmacology, and patient management. The exam contains approximately 150 multiple-choice questions and is delivered via computer at approved testing centers. A separate Law and Ethics exam (50 questions) tests knowledge of the California Dental Practice Act.

The clinical examination for California RDA candidates tests practical skills including coronal polishing, taking alginate impressions, placing and removing matrices, and dental radiography procedures. Candidates must demonstrate technique on a manikin or patient under examiner observation.

DANB Exams are used in states that have adopted DANB component exams as part of or in lieu of their own board exam. The three core components are:

• General Chairside (GC): 120 questions, 90 minutes — covers chairside procedures, instruments, materials, and patient care
• Radiation Health and Safety (RHS): 100 questions, 75 minutes — covers radiographic techniques, safety, and quality assurance
• Infection Control (ICE): 100 questions, 75 minutes — covers OSHA standards, sterilization, and disease transmission prevention

DANB exams are computer-adaptive and administered through Prometric testing centers nationwide. Passing scores are scaled; a score of 75 is generally required on each component. Once all three components are passed, you earn the CDA credential, which may satisfy state licensure requirements or be submitted alongside a state application.

Regardless of pathway, allow 4–12 weeks of focused study time. Use practice tests to identify weak areas early, particularly in radiography safety and infection control, which historically have higher failure rates.

RDA Salary Outlook

Registered Dental Assistants earn competitive wages within the dental office setting, with compensation influenced by state, years of experience, expanded function authorization, and practice type (general dentistry vs. specialty).

According to the U.S. Bureau of Labor Statistics (BLS), dental assistants earned a median annual wage of approximately $45,960 as of the most recent national survey. However, RDAs with expanded function authorization — particularly in states like California — often earn considerably more due to the additional procedures they are legally permitted to perform.

State-by-state salary benchmarks:

• California: Median $52,000–$62,000/year; RDAEFs (extended functions) can exceed $70,000 in metropolitan areas
• Texas: Median $38,000–$48,000/year; specialty dental offices (orthodontics, oral surgery) pay a premium
• New York: Median $44,000–$54,000/year; New York City metro significantly above state median
• Washington State: Median $50,000–$60,000/year; strong demand in the Seattle metro area

Career advancement opportunities for RDAs include moving into dental office management, dental sales, dental school clinic supervision, or pursuing further education toward dental hygiene licensure. The job outlook for dental assistants is projected to grow 7% over the next decade — faster than average — driven by an aging population requiring more dental care and the expansion of dental service organizations (DSOs) across the U.S.