The DANB Certified Dental Assistant (CDA) credential isn't a single test — it's three separate exams from the Dental Assisting National Board: Radiation Health and Safety (RHS), the Infection Control Exam (ICE), and General Chairside (GC).
Passing all three within DANB's combination window earns the full CDA.
RHS and ICE have no prerequisites and can be taken on their own; GC is the component tied to DANB's eligibility pathway.
Here's what each one actually tests.
The CDA is three exams, not one
The Dental Assisting National Board's Certified Dental Assistant (CDA) is the most common national credential a dental assistant pursues, but it isn't earned with a single test.
It's built from three separate component exams — Radiation Health and Safety (RHS), the Infection Control Exam (ICE), and General Chairside (GC) — and passing all three within DANB's combination window is what earns you the full CDA.
Each component can be scheduled and taken on its own, which matters more than it sounds: RHS and ICE have no prerequisites, so a brand-new assistant can sit either one before finishing a program or logging any hours.
This page focuses on what each of the three actually tests.
For how the national CDA relates to state credentials like RDA and LDA — a completely different question — see our guide to CDA vs. RDA and the dental assistant title maze.
Exam specifics change — verify directly with DANB
RHS: Radiation Health and Safety
RHS tests the knowledge behind safe dental radiography: radiation physics and biology, protecting the patient and the operator, safe equipment operation, and the infection-control practices specific to taking x-rays.
It's the component most directly tied to a single everyday duty — producing diagnostic images without unnecessary radiation exposure.
Because RHS has no prerequisites, it's typically the first of the three components a new assistant takes, often before finishing a training program.
That timing lines up with the job market, too: many states accept a passing RHS score toward the radiology permit they require before an assistant may operate x-ray equipment.
Our guide on whether a dental assistant can take x-rays covers how that permit requirement plays out state by state.
ICE: Infection Control Exam
ICE covers the infection-control and sterilization practices that run through every part of a dental office: instrument sterilization and monitoring, barrier technique, handling contaminated materials and sharps, and the safety practices that protect patients and staff from cross-contamination.
Like RHS, ICE has no prerequisites, so it stands on its own rather than requiring you to be partway toward the full CDA.
Some assistants take it purely to document infection-control competency for an employer, independent of whether they ever sit GC or earn the full certification — infection control is foundational enough to the job that the standalone credential carries weight by itself.
GC: General Chairside
General Chairside is the broadest of the three components.
It tests the wider body of dental-assisting knowledge that doesn't fall specifically under radiography or infection control — chairside procedures and patient care, dental sciences fundamentals, and the everyday clinical support an assistant provides throughout a procedure.
GC is also where DANB's eligibility pathway comes in.
Unlike RHS and ICE, sitting for GC — and being awarded the full CDA — typically requires you to first qualify through one of DANB's pathways: graduating a CODA-accredited dental assisting program, or documenting roughly 3,500 hours of on-the-job experience.
Confirm the current pathways directly with DANB before you plan around one, since eligibility requirements are updated periodically.
Neither pathway can be satisfied by online coursework alone — see our guide on whether you can become a dental assistant online for why that hands-on requirement never goes away.
How the three combine into the full CDA
There's no mandated order for the three exams — many assistants take RHS first simply because it has no prerequisites and doubles as a radiology permit, but DANB doesn't require that sequence.
What does matter is timing: all three components must be passed within DANB's combination window, currently five years, for DANB to award the full CDA certification.
Exceed that window without completing all three, and you may need to retake an earlier component under DANB's current retake and reinstatement rules.
Because format, fees, and testing logistics for each exam are subject to change, DANB's own candidate guide is the source to check before you register for any component.
Why some assistants stop at one or two components
Because RHS and ICE stand on their own, not every assistant who takes one is working toward the full CDA.
Some take only RHS to satisfy a state's radiology permit requirement and never sit ICE or GC at all.
Others add ICE for an infection-control credential an employer values, without pursuing General Chairside or the full certification.
That's a different question from "which title do I need," which our CDA vs. RDA guide answers.
This is about how much of DANB's exam ladder you actually need to climb, which depends on your state's requirements and what you're trying to prove to an employer.
Where to confirm current exam details
This page describes the durable structure of the CDA — three components, a combination window, and two different eligibility tracks.
What it deliberately doesn't do is publish exam fees, question counts, or exact formats, because DANB updates those details, and a stale number is worse than no number.
Before you register for RHS, ICE, or GC, check DANB's current candidate guide for eligibility, cost, and format, and confirm with your state dental board whether it accepts any of the three toward its own credentialing or permit requirements.
This article is general career information, not test-prep or legal advice. DANB's exam content, eligibility pathways, and fees change over time — confirm current requirements directly with DANB and your state dental board.