What Is the NBDHE Exam? Format, Components, and What to Expect

The National Board Dental Hygiene Examination (NBDHE) is the standardized written exam for dental hygiene licensure in the United States. It's developed by the Joint Commission on National Dental Examinations (JCNDE) and accepted by every U.S. state board for the written portion of licensure. If you're a final-year student or a recent graduate, this is the exam standing between you and your RDH credentials.

The Format

The NBDHE is a two-component exam, sat on the same day:

• Component A — Discipline-Based: 150 questions, 3 hours. Discrete multiple-choice items across the basic and clinical sciences.
• Component B — Case-Based: 150 questions, 4 hours. Twelve patient cases, each with a medical history, dental history, radiographs, periodontal charting, and a sequence of questions tied to the case.

Total seat time including breaks runs 7+ hours. There are roughly 50 unscored pilot questions mixed in across both components — you won't know which.

Component A — Discipline Weights

The Component A blueprint distributes its 150 questions across seven disciplines. Approximate weights (verify the current JCNDE Candidate Guide for exact percentages):

• Dental Hygiene Science — ~36%
• Anatomical Sciences — ~14%
• Pathology — ~13%
• Pharmacology — ~11%
• Physiology — ~9%
• Biochemistry & Nutrition — ~9%
• Microbiology & Immunology — ~8%

Dental Hygiene Science is by far the largest slice. If you have to pick one area to over-prepare, that's it.

Component B — Case Anatomy

Each of the twelve patient cases gives you:

• A patient profile (age, chief complaint, social history)
• A medical history (medications, comorbidities, allergies)
• A dental and periodontal history (existing restorations, perio status, oral hygiene)
• Radiographic images (full-mouth series, bitewings, or panoramic where indicated)
• Periodontal charting and intraoral findings
• ~12 questions covering treatment planning, oral health education, instrumentation choices, pharmacologic considerations, and emergency preparedness

The same case stays with you across all of its questions, so reading the case carefully once pays dividends across the whole sequence.

Scoring

The NBDHE uses a scaled scoring system. The minimum passing score is 75 (scaled) on each component independently — you must pass both. Raw-to-scaled conversion is determined through standard-setting and is not published as a fixed raw cutoff. Verify the current passing standard in the JCNDE Candidate Guide for your testing window.

Eligibility

You're typically eligible to sit the NBDHE once you've completed (or are in the final term of) an accredited dental hygiene program. Specific eligibility — including any program-completion documentation, your testing window, and accommodations — is set by JCNDE; confirm at the time of application.

Retake Policy

Candidates who don't pass may retake after a waiting period set by JCNDE, with a cap on total attempts. The current policy is published in the Candidate Guide and is updated periodically.

How to Prepare

There's no single "right" way, but a structured plan beats marathon study sessions:

1. Map the blueprint. Know the Component A discipline weights and the Component B case structure cold. Don't waste time over-studying low-weight areas.
2. Build daily reps with spaced repetition. Drug names, microbe-disease pairings, and instrumentation choices respond well to flashcards reviewed at increasing intervals.
3. Practice case-based reasoning. Component B doesn't reward isolated facts — it rewards reading a case once and answering 12 questions efficiently. Drill that pattern.
4. Time yourself. Four hours on Component B is long enough to drift if you haven't built endurance.
5. Mock the full day. At least once before test day, sit a full Component A + B sequence with realistic breaks.

How CertCleared Helps

CertCleared's NBDHE track ships:

• A Component A mock exam covering all seven disciplines, blueprint-weighted
• A Component B patient case bank — 12 cases, ~144 SME-reviewed case-based questions
• FSRS-powered flashcards across every Component A discipline
• Domain-level progress tracking so you know exactly which discipline is dragging your score

Free tier gives you a starter deck and 10 questions per day. Pro unlocks the full bank and Component A mock; Premium adds the full Component B case bank and unlimited mock attempts.

CertCleared is an independent prep platform. We are not affiliated with, endorsed by, or sponsored by JCNDE, the ADA, or any state dental board. All references to the NBDHE blueprint are based on publicly available JCNDE materials at the time of writing.