"CDA" almost always means the Dental Assisting National Board's Certified Dental Assistant — a national certification you earn by passing exams.
"RDA" means Registered Dental Assistant — a credential a state dental board grants to let you work in the states that use that title.
They answer different questions: certification proves competency nationally, while state registration or licensure is the legal permission to perform duties where you work — and a certification does not replace your state's permission.
Two different systems, one pile of acronyms
The confusion around dental assistant titles comes from mixing up two separate systems.
One is national certification — a credential you earn from a national certifying body to prove you've met a competency standard.
The other is state regulation — the registration, license, or permit your state requires before you may legally perform certain duties.
The DANB CDA lives in the first system; RDA, LDA, and EFDA live in the second.
You can hold the national certification and still need a state credential to work — and in some states you can work without the national certification at all.
Which matters for you depends entirely on where you practice.
The "CDA" collision — read this first
The national credential: DANB's CDA
The Certified Dental Assistant (CDA) is the national certification from the Dental Assisting National Board (DANB).
It's built from three separate exam components — Radiation Health and Safety (RHS), Infection Control (ICE), and General Chairside (GC) — which DANB lets candidates take separately or together.
(For what each component actually tests, see our breakdown of the DANB CDA exam.)
DANB sets two eligibility pathways: graduating from a CODA-accredited dental assisting or dental hygiene program, or a high school diploma or equivalent plus at least 3,500 hours of approved work experience — each also requires current hands-on CPR, BLS or ACLS.
Confirm the current pathways and any exam window directly with DANB, since eligibility rules change.
DANB describes the CDA as "recognized or required in many states," but on its own it is a certification, not a license to work.
State titles: RDA, LDA, and EFDA
Your state dental board — not DANB — controls whether and how you may work, and each state names its credential differently.
Titles include RDA (Registered Dental Assistant, used in California and other states — which states use the title, and what each board requires), LDA (Licensed Dental Assistant — Minnesota's title for its licensed dental assistants), and expanded-function titles like EFDA, EDDA, or California's RDAEF for the expanded-function level.
Which title your state uses matters, because the requirements behind them differ too.
The practical takeaway: the credential that legally lets you work is the one your state issues, whatever it happens to be called — and holding DANB's CDA does not replace it.
What's the difference between a certified and a registered dental assistant?
A certified dental assistant and a registered dental assistant hold two different kinds of credential.
Certified means you passed a national competency exam — DANB's CDA.
Registered means a specific state's dental board has authorized you to work there.
Certification signals competency; registration is legal permission.
That's why they don't substitute for each other.
In North Dakota, an assistant holding DANB's CDA must still register with the board before doing duties beyond an unregistered assistant's.
In New Mexico, board certification and DANB certification are distinct — a CDA alone doesn't qualify an assistant to perform expanded functions there.
State credentials are issued state by state, each with its own requirements, so confirm with the board where you work or plan to work.
They interact, though.
Some states accept the DANB CDA — or one of its components — toward their own requirements; DANB describes the CDA as "recognized or required in many states."
RHS is one example: some states accept a passing score as the radiology qualification they require before you may take x-rays (Connecticut, for example, permits x-ray delegation only to assistants who have passed RHS or a radiation competency assessment from a CODA-accredited Connecticut program), which is one reason an assistant might sit that component even in a state that doesn't require the full CDA.
California runs the overlap the other way: current DANB CDA certification is one of the five routes into that state's RDA license.
That competency signal shows up in pay data too: in DANB's own 2026 salary survey, CDAs reported a median of $28 an hour against $24 for non-certified assistants — a self-reported survey from the body that sells the credential (how to read that gap).
The CDA itself doesn't grant any new legal duties.
So which one do you actually need?
It depends on your state and the duties you want to perform.
Some states don't require a license for entry-level assisting, so you can start chairside with on-the-job training and no credential for basic duties.
Others ask for more: Minnesota licenses dental assistants, Texas requires a radiology certificate before an assistant positions or exposes x-rays, and California requires a board-approved radiation safety course before an assistant performs radiographic procedures.
A reliable rule of thumb: find out what your state board requires first, then decide whether the national CDA helps you get there.
DANB describes the CDA as "recognized or required in many states" — how each state treats it varies.
What it never does is override your state's own rules.
How to confirm what your state requires
Go to two authorities.
For the national certification — components, eligibility, and fees — DANB is the source.
For what you're legally allowed to do where you work, your state dental board publishes the practice act, credential titles, and permit requirements; the ADAA's state-by-state pages and the AAPD's summary of state laws on dental assistants are useful starting maps.
Where a school's marketing, a job posting, and the state rule seem to disagree, the state board wins.
Because these rules change, note the date you checked and re-verify before you enroll in a program or apply for a permit.
This article is general career information, not legal advice. Certification pathways and state scope-of-practice rules vary and change over time — confirm current requirements with DANB and your state dental board.