NBDHE Case-Based Questions: How to Master the 150 Integrated Items

Nearly half of the National Board Dental Hygiene Examination isn't a fact test at all. Session Two hands you 12 to 15 patient cases and asks you to work like a clinician: read a history, interpret a perio chart, study a radiograph, and choose the best next step. Students who fail with a 71, 72, or 74 usually didn't miss definitions. They missed cases. Case performance is where borderline scores are decided. Here's how the component is built, and how to train for it. Master the patient box rule, read each question before opening the charts, stage with the worst available indicator, drill CAL calculations and ASA scenarios, and brain-dump your thresholds before the timer starts.

How the Case Component Is Built

Session Two gives you 4 hours for 150 case-based questions, split into two blocks of roughly 75 questions with an optional 15-minute scheduled break between them. Across those blocks you work through 12 to 15 patient cases.

Every exam includes at least one case of each required type: geriatric, adult-periodontal, pediatric, special needs, and medically compromised. Roughly 80% of cases involve adult patients and 20% involve children, so pediatric cases are few but guaranteed.

Each case arrives as a bundle of materials: patient histories, dental charts, periodontal charts, radiographs, and intra- and extra-oral photographs. The questions attached to a case can pull from any of the seven clinical skill areas, from assessment and radiographs through care planning, periodontal procedures, preventive agents, supportive treatment, and professional responsibility. One case can test half your textbook. (No wonder students feel overwhelmed at first — we did too.)

One structural footnote: some items on every form are unscored experimental questions, indistinguishable from scored ones. The coping rule passers repeat: you'll see things you never heard of, so answer the question and move on. There's no penalty for guessing.

The Patient Box Rule

The defining mechanic of the case section is the patient box: only the information presented at that visit exists. If no allergies are listed, the patient has no known allergies. If no blood pressure is recorded, you don't get to assume one.

The rule cuts both ways. Don't import outside knowledge into a case, and don't invent findings the chart doesn't show. Every correct answer lives inside the box. Most wrong answers come from reasoning with facts the exam never gave you.

Mine the Medical History

Case materials hide the decisive facts in the med list. Passers recall mining histories for diabetes, hypertension, hyperlipidemia, depression, osteoporosis treated with bisphosphonates, warfarin, hepatitis, and COPD, then answering which medication or procedure is contraindicated given exactly that list. The nitroglycerin and erectile dysfunction medication interaction is the classic recalled example.

Read the history like a pharmacology checklist before you open a single chart. The case that looks like a perio question is often a medication question wearing a perio chart.

Read the Question First

The rookie move is opening a case and studying every document before reading a single question. With 12 to 15 cases carrying roughly 10 to 13 questions each, that habit burns the clock.

The method passers teach instead:

1. Read the question stem first.
2. Identify exactly which data it needs.
3. Go to the history, chart, or radiograph and pull only that.

Most case questions require just one or two pieces of the case materials. Reading first turns a scavenger hunt into a retrieval task. Students consistently report it's the difference between finishing Session Two comfortably and sprinting through the final case.

The Worst-Available-Indicator Rule

Real perio data is messy, and the exam copies that. You'll see perio charts with probing depths but no CAL listed, no bleeding points, and no mobility column. You'll find recession or mobility mentioned only in the medical history or buried in the dental chart notes.

The rule passers teach: classify and stage from the worst available indicator you can find. If the perio chart is silent, go hunting in the history and the dental chart. And when probe depths and radiographs disagree, radiographic bone loss trumps probe depths. A patient with shallow pockets and obvious bone loss on film is not a healthy periodontium.

Know one more distinction the exam loves: health on an intact periodontium versus health on a reduced periodontium. A patient with recession, stable probing depths, and no current inflammation is not automatically a gingivitis case.

Staging and Grading: The Most-Cited Case Skill

Ask recent passers which single skill the case section demands and the answer comes back the same: periodontal staging and grading under the 2017 AAP classification. Students report forms where nearly every case asked for a stage or a grade.

Two drills are therefore non-negotiable:

• CAL calculation. Clinical attachment loss is probing depth plus recession measured from the cementoenamel junction. Drill it until a chart with mixed recession and pocketing takes you seconds, not minutes.
• Severity thresholds. Know the CAL and bone loss boundaries between stages and the maximum probing depth bounds per stage, so a borderline chart lands in the right stage instead of the adjacent one.

Expect the case to hand you a chart that sits on a boundary. That's the point: the exam wants to know whether you know where the boundaries are.

ASA Classification Scenarios

Cases lean hard on ASA physical status, and passers recall the same scenarios again and again: unstable angina, a TIA more than 6 months ago with hypertension and type 2 diabetes, stable angina.

The consensus rule from students who passed:

• Controlled systemic disease: ASA II.
• Uncontrolled systemic disease: ASA III minimum.
• Life-threatening or unstable findings, like unstable angina: ASA IV.
• Classify by the worst current finding, never the best one.

For the blood pressure cutoffs, use the memory hook students pass around: ASA II, III, IV with systolic 140-160-200 and diastolic 90-95-115. Say it as a rhythm until it's automatic.

The Brain Dump on the Dry-Erase Board

Pearson VUE provides a laminated note board and marker, and you may not write on it until the exam starts. Your window is the optional 15-minute tutorial. Passers use it to dump a one-page memory sheet: staging and grading thresholds, ASA classes with the BP string, pharm suffixes, eruption dates, GV Black classes, cranial nerves, and occlusion classes.

The brain dump only works if the sheet is automatic. Rebuild it from memory every morning in the final weeks, and if you can't reproduce it in under five minutes, keep drilling. Students credit this ritual with calming nerves and speeding up case work all afternoon. Our flashcards and memory guide covers the construction in detail.

Time Management Per Case

Four hours for 150 questions works out to about a minute and a half per item, or roughly 15 to 20 minutes per case depending on how many cases your form carries. Don't marathon a confusing case. Flag the stubborn items, finish the block, and take the scheduled 15-minute break between the two case blocks. Students who skip breaks describe their brains turning to mush in the final stretch, and that stretch is 75 questions long.

Resist the urge to sprint. Failure analyses of fast finishers are blunt: taking three more seconds per question helps more than finishing early. Read every stem to its last word, especially the capitalized EXCEPT and NOT items, and let the clock take care of itself.

Practice Cases Like They're the Real Exam

The highest-leverage habit in this entire guide: rehearse cases in the real format until they feel routine. Students who drill complete case blocks with patient boxes, perio charts, and radiographs before test day consistently report that the real cases feel familiar rather than foreign. Case practice isn't review. It's rehearsal. Keep an error log of every missed case item, note which rule broke down, and drill that rule again before your next session.

That's why our 6 full-length mock exams carry explanations detailed enough to teach the reasoning, not just the key. For a full mock-exam review protocol, read our guide to NBDHE mock exams.

Why 71 to 74 Fails Trace Back to Cases

On the National Board Dental Hygiene Examination, the failing score report breaks performance into 13 discipline areas plus the case area. Educators who analyze those reports give the same advice to students in the 71 to 74 band: there's a high chance case studies are what you missed. If that's you, the fix isn't more rereading. It's structured case repetition with the rules above, and our retake strategy guide lays out that plan week by week.

Cases are 43% of the exam and the deciding factor in most borderline scores. Learn the patient box rule, read questions before charts, stage with the worst available indicator, automate the brain dump, and rehearse full case blocks on a computer. Do that, and Session Two becomes the part of the dental hygiene boards you're most ready for.