ACJ Exam Study Guide (2026)
Everything the NDEB Assessment of Clinical Judgement (ACJ) tests, topic by topic: what each section covers, the facts that come up most, and how to study it. Pair it with the free 15-question practice test.
The exam at a glance
| Questions | About 150 single-answer and multi-answer multiple-choice questions (the NDEB lists 120 to 150), many built on case histories, charts, radiographs and photographs |
|---|---|
| Time | About 5 hours of testing with one scheduled break (a 5.5-hour session) |
| Passing score | A test-equated, re-scaled score of 75 (the NDEB's standardized passing score); multi-answer questions score 1 only if every correct option and no wrong option is chosen |
| Format | Closed book, computer-based, case-based single- and multi-answer multiple choice |
| Certifying body | The National Dental Examining Board of Canada (NDEB) |
| Test provider | Computer-based at Prometric test centres in Canada and select international locations, including Australia and New Zealand |
Mind map: the whole exam on one screen
Read the complete ACJ study notes for “Oral Medicine, Oral Pathology and Oral Surgery”
Our first full set of comprehensive notes, about 15 minutes of reading: Describe before you diagnose · Biopsy decisions · Jaw lesions to recognize · Infections: who stays in the chair and who goes to hospital · Surgery in medically complex patients, a worked exam example, the traps examiners use and a one-minute recap. Create a free account to read it and see how premium notes work before you decide.
1. Oral Medicine, Oral Pathology and Oral Surgery
The largest ACJ area (about 25%): diagnosing mucosal and jaw lesions from photographs, radiographs and histories, deciding when and how to biopsy, and managing surgical problems and infections.
Key facts
- Describe before you diagnose: site, size, margins (well or poorly defined), internal structure (radiolucent, radiopaque, mixed), locularity and effect on teeth (displacement, resorption).
- Small, well-circumscribed benign-looking lesions: excisional biopsy. Large or suspicious lesions: incisional biopsy of the most representative area, or urgent referral.
- Pericoronal radiolucency attached at the CEJ: dentigerous cyst. Multilocular posterior mandible: ameloblastoma or odontogenic keratocyst. Always send tissue for histology.
- Vital teeth with periapical radiolucencies point to a non-endodontic cause, such as cemento-osseous dysplasia.
- Spreading infection with airway signs (raised tongue, dysphagia, drooling, trismus, fever): emergency hospital referral.
- Antiresorptive therapy (especially IV bisphosphonates or denosumab for cancer) raises the risk of medication-related osteonecrosis of the jaw after extractions.
Flashcards
Exam tip: With a photo or radiograph, write a one-line description before you look at the options. The options are often lesions that look alike.
2. Pharmacotherapeutics and Medically Complex Patients
About 22% of the ACJ: drug choices and interactions, endocarditis prophylaxis, anticoagulants, diabetes, cardiovascular disease, medical emergencies, geriatrics and local anesthesia in medically complex patients.
Key facts
- Endocarditis prophylaxis (2021 AHA): highest-risk cardiac conditions only, for procedures that manipulate gingiva or the periapical region. Amoxicillin 2 g orally 30 to 60 minutes before.
- Penicillin allergy: cephalexin 2 g if there's no history of anaphylaxis, angioedema or urticaria; otherwise azithromycin or clarithromycin 500 mg or doxycycline 100 mg. Clindamycin is no longer recommended.
- Warfarin: check the INR within 24 hours; simple extractions can usually proceed when it's in the therapeutic range, with local hemostatic measures. DOACs usually aren't stopped for simple procedures.
- Hypoglycemia (below 4.0 mmol/L) in a conscious patient: 15 g fast-acting carbohydrate, recheck in 15 minutes.
- Elective dental treatment is usually deferred if blood pressure is 180/110 mmHg or higher.
- Epinephrine in local anesthetic is safe in most cardiac patients at normal dental doses; limit it in uncontrolled cardiovascular disease.
- NSAIDs interact with anticoagulants, antihypertensives and lithium; avoid them in kidney disease and late pregnancy.
Flashcards
Exam tip: Read the medications list before the chief complaint. Half the ACJ's pharmacology questions hide in it.
3. Cariology and Restorative Dentistry
About 18% of the ACJ: caries risk assessment, non-surgical caries management, deep caries and pulp protection, choosing restorations, and diagnosing cracked teeth and failing restorations.
Key facts
- Assess caries risk (history, diet, saliva, fluoride, plaque, medical status) and match prevention and recall to it.
- Non-cavitated lesions: arrest with fluoride, sealants or resin infiltration, diet change and plaque control.
- Deep lesions in vital teeth without irreversible pulpitis: selective removal to soft dentin near the pulp, hard dentin at the margins, then seal.
- 38% silver diamine fluoride arrests cavitated lesions without drilling; it stains them black.
- Cracked tooth: pain on release of biting, often reversible cold pain, normal radiograph. Cuspal coverage protects it.
- Recurrent caries at margins, open contacts and overhangs are common reasons to replace restorations; repair is often better than replacement.
Flashcards
Exam tip: The ACJ rewards the least invasive treatment that fully solves the problem. If two options both work, choose the one that keeps more tooth.
Test yourself on these topics
Take the free 15-question ACJ test, then save your results to unlock your Readiness Score and the mistakes bank.
4. Periodontics
About 15% of the ACJ: reading periodontal charts, staging and grading periodontitis, necrotizing and acute conditions, treatment planning and supportive care.
Key facts
- The ACJ periodontal chart lists vestibular then lingual probing depths, recession and bleeding, with mobility (Miller 1 to 3) and furcation (Class I to III with the surface) at the bottom.
- Clinical attachment loss = probing depth + recession (when the margin is apical to the CEJ).
Flashcards
Exam tip: Add recession to probing depth on every chart question. Attachment loss, not pocket depth, decides the stage.
5. Endodontics
About 10% of the ACJ: pulp and periapical diagnosis from tests and radiographs, emergency treatment, retreatment versus surgery, and restoring root-filled teeth.
Key facts
- Two-part diagnosis: the pulp (normal, reversible pulpitis, symptomatic or asymptomatic irreversible pulpitis, necrosis, previously treated or initiated) and the apical tissues.
- Apical diagnoses: normal, symptomatic apical periodontitis (tender), asymptomatic apical periodontitis (radiolucency, not tender), acute apical abscess (swelling), chronic apical abscess (sinus tract).
Flashcards
Exam tip: Most endodontic diagnosis questions are solved with three findings: cold response, percussion and whether there's swelling or a sinus tract.
6. Orthodontics and Pediatric Dentistry
About 10% of the ACJ: interceptive orthodontics, crossbites, space management, eruption problems, pediatric caries risk and prevention, and pulp therapy and trauma in children.
Key facts
- Anterior crossbite with a functional forward shift and enough space: correct early, e.g. a removable appliance with a finger spring.
- Posterior crossbite with a lateral functional shift: correct early, often with maxillary expansion.
Flashcards
Exam tip: Interceptive orthodontics questions ask 'treat now or wait?'. Functional shifts and trauma risk mean treat now; skeletal problems usually mean refer.
How to pass
- The ACJ is case-based. Read the medical history, medications and vital signs first: they change the answer to more than one question.
- Multi-answer questions score 1 only if you pick every correct option and no wrong one; a single wrong pick scores 0. Choose only the options you're sure of.
- Oral medicine, pathology and oral surgery are the biggest area (about 25%), followed by pharmacotherapeutics and medically complex patients (about 22%).
- Radiographic interpretation is in every section. Practise describing a lesion's site, margins, internal structure and effect on nearby teeth before naming it.
Frequently asked questions
How long should I study for the ACJ exam?
Most working candidates need 4 to 8 weeks at 45 to 60 minutes a day. Book your exam once your Readiness Score has stayed at 80 or higher for about a week.
Can I take the ACJ exam online?
No. The NDEB doesn't offer the AFK or ACJ by remote proctoring. The ACJ is taken at Prometric test centres in Canada and select international locations; the AFK is taken at Prometric test centres or as a paper booklet at select exam sites in Canada. Format: closed book, computer-based, case-based single- and multi-answer multiple choice. Check the current NDEB Protocol for the rules.
What score do I need to pass the ACJ exam?
A test-equated, re-scaled score of 75 (the NDEB's standardized passing score); multi-answer questions score 1 only if every correct option and no wrong option is chosen. The exam has about 150 single-answer and multi-answer multiple-choice questions (the ndeb lists 120 to 150), many built on case histories, charts, radiographs and photographs and a time limit of about 5 hours of testing with one scheduled break (a 5.5-hour session).
What are the most tested topics?
The outline covers oral medicine, oral pathology and oral surgery, pharmacotherapeutics and medically complex patients, cariology and restorative dentistry, periodontics, endodontics, orthodontics and pediatric dentistry. Use the free practice test to see which ones you need most.
The premium ACJ study path
Premium ACJ prep is studied one topic at a time. Each step starts with that topic's key notes and flashcard deck, then its own question sets of 25, so you master one topic before you move to the next. When every topic is strong, the 6 full mock exams show you're ready.
Your step-by-step study path
- 1Oral Medicine, Oral Pathology and Oral Surgery10 key notes, 135 flashcards, then 500 practice questions in 20 sets of 25Notes free with an account
- 2Pharmacotherapeutics and Medically Complex Patients10 key notes, 135 flashcards, then 500 practice questions in 20 sets of 25Premium
- 3Cariology and Restorative Dentistry10 key notes, 135 flashcards, then 500 practice questions in 20 sets of 25Premium
- 4Periodontics10 key notes, 135 flashcards, then 500 practice questions in 20 sets of 25Premium
- 5Endodontics10 key notes, 130 flashcards, then 500 practice questions in 20 sets of 25Premium
- 6Orthodontics and Pediatric Dentistry10 key notes, 130 flashcards, then 500 practice questions in 20 sets of 25Premium
- Final step: 6 full mock exams150 questions each, timed like test day. Pass them, then book your exam.Premium
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- One NDEB assessment of your choice: the AFK or the ACJ
- 3,000 practice questions + 6 full mock exams per exam
- 800 flashcards + 60 key notes per exam, by topic, plus mind maps
- Spaced repetition + mistakes bank
- Readiness Score & detailed reports
- Video lessons as they release
- Content updates during your access
- 5 bonuses: high-yield dental values sheet, radiolucency and lesion atlas, study planner and more
- Pass Guarantee: complete the prep, pass or 100% back
Renews once a year until you cancel. We email you before each renewal. Cancel any time from your account; you keep access until the end of the year you've paid for.
Summarized from the National Dental Examining Board of Canada's official candidate information and the rules cited, checked October 2026. Confirm current requirements with The National Dental Examining Board of Canada (NDEB).