ADC Part 1 Periodontics: High-Yield Topics, Example Questions & Study Tips
Periodontics carries roughly 12% of the ADC Part 1 written exam - ≈34 of 280 questions. Below: the high-yield topics to master, the classic traps that cost candidates marks, an ADC-style example question, and how to study this subject efficiently.
High-yield topics for Periodontics
| Topic | What to focus on |
|---|---|
| 2017 World Workshop classification | staging (I–IV) and grading (A–C) - the single most examined perio topic |
| Periodontitis vs gingivitis diagnosis | clinical attachment loss vs bleeding on probing; case-based diagnosis questions |
| Non-surgical therapy | scaling and root planing outcomes, re-evaluation timing, when to refer or go surgical |
| Furcation involvement | Glickman/Hamp classifications and prognosis implications |
| Perio-systemic links | diabetes bidirectionality, smoking's effect on treatment response and bleeding |
| Acute conditions | necrotising gingivitis/periodontitis, perio abscess vs periapical abscess discrimination |
| Peri-implant disease | mucositis vs peri-implantitis, risk factors, maintenance |
Common areas candidates struggle with
- Applying the 2017 classification correctly - many candidates stage by pocket depth (wrong) instead of interdental CAL / radiographic bone loss (correct)
- Distinguishing perio abscess from periapical abscess when the patient presents acutely - vitality testing is the key discriminator
- Assigning grade modifiers - smokers and diabetics shift the grade, not the stage
- Peri-implant mucositis vs peri-implantitis - the presence of bone loss beyond initial remodelling is the discriminator
- Knowing when to refer for surgical periodontal treatment vs continue non-surgical maintenance
Classic exam traps
- Staging by pocket depth instead of interdental clinical attachment loss / radiographic bone loss
- Perio abscess vs endo abscess - check vitality: perio abscess teeth are usually vital
- Expecting bleeding in smokers - nicotine vasoconstriction masks BOP, underestimating disease
- Forgetting grading modifiers: smoking and diabetes shift grade, not stage
Example ADC-style question
Question
A 45-year-old smoker presents with generalised pocketing 5-7 mm, interproximal CAL of 4-5 mm and radiographic bone loss of 30-45% at multiple sites. There is no tooth loss. What is the periodontitis stage and grade?
- Stage II, Grade A
- Stage II, Grade B
- Stage III, Grade B
- Stage III, Grade C
Answer: D
Bone loss extending to mid-third of root (30-45%) = Stage III. Grade is elevated to C because of the smoking risk factor (>10 cigarettes/day). Stage is determined by severity and complexity; grade by risk factors and rate of progression.
This is one worked example. There are hundreds more scenario-based periodontics MCQs inside the PassADC question bank - with per-option explanations on the ones that matter most.
Key concepts to revise
- 2017 staging criteria (Stage I-IV) - the exact thresholds for CAL and radiographic bone loss
- 2017 grading criteria (Grade A-C) - including smoking and diabetes modifiers
- Perio abscess vs periapical abscess discriminators (vitality, sinus tract origin)
- Non-surgical therapy re-evaluation timing (4-6 weeks) and success criteria
- Peri-implant mucositis vs peri-implantitis definitions
- Furcation classifications (Glickman I-IV, Hamp)
- Necrotising periodontal diseases - clinical hallmarks
How to study Periodontics for the ADC Part 1
- Build a one-page staging/grading table and re-draw it from memory weekly
- Practise case vignettes: age + CAL + bone loss % → stage and grade in under a minute
- Know re-evaluation at 4–6 weeks cold - sequencing questions are frequent
How to test your readiness in Periodontics
The exam tests this subject through clinical vignettes, so practise it the same way - scenario-based MCQs with explanations, not isolated fact recall. The fastest way to know whether periodontics is a strength or a gap is to take a diagnostic across all 10 subjects and compare your accuracy in this subject against the exam weighting.
Once you know where you stand, target the weak areas above with daily practice, review every wrong answer's explanation the same day, and sit at least two full-length timed mocks before booking the real exam.
Want to see whether periodontics is actually one of your weak areas?
6 ADC-style questions across the top subjects. Free, instant, no credit card.
Check my ADC readinessRelated ADC Part 1 resources
Start with the ADC Part 1 preparation hub, plan the next 8 weeks with the study guide, or drill more periodontics MCQs in the question bank. Also see the full ADC Part 1 exam format guide and how to pass ADC Part 1.
Frequently asked questions
How much periodontics is in the ADC Part 1?
Approximately 12% - about 34 of 280 questions. The 2017 classification is by far the most examined periodontics topic.
What's the fastest way to learn the 2017 perio classification?
Build a one-page staging (I-IV based on CAL and bone loss) and grading (A-C with smoking/diabetes modifiers) table. Redraw from memory weekly until you can stage and grade any vignette in under a minute.
How do you tell a perio abscess from a periapical abscess?
Check pulp vitality. A perio abscess arises from an infected periodontal pocket and the tooth is usually vital. A periapical abscess arises from pulp necrosis and the tooth is non-vital. Radiographs and sinus tract origin (marginal vs apical) also help.
When do you refer periodontitis for surgical treatment?
After thorough non-surgical therapy and re-evaluation at 4-6 weeks, if residual pockets ≥5 mm with bleeding on probing persist and the patient is compliant with hygiene, surgical management is considered.
Where do you actually stand?
30 questions weighted to the official ADC blueprint. Free, instant, no credit card.
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PassADC is an independent study platform and is not affiliated with, endorsed by, or sponsored by the Australian Dental Council. Exam details change - always confirm current format and fees at adc.org.au.