Periodontics Prometric exam questions with answers

1. Question 1Classification and Diagnosismedium

   A 48-year-old has a maximum interdental CAL of 6 mm, bone loss into the middle third of the root, probing depths up to 7 mm and no teeth lost to periodontitis. What is the stage?

   1. AStage I
   2. BStage II
   3. CStage IV
   4. DStage III
   Show answer and explanation▾

   Answer: D. Stage III

   Interdental CAL of 5 mm or more with bone loss into the middle third or beyond defines Stage III, and PD of 6 mm or more is a Stage III complexity factor. Stage IV needs loss of 5 or more teeth to periodontitis or complex rehabilitation needs.

2. Question 2Classification and Diagnosishard

   In a patient with an intact periodontium and no attachment loss, what minimum proportion of bleeding-on-probing sites defines a gingivitis case?

   1. A10%
   2. B5%
   3. C20%
   4. D50%
   Show answer and explanation▾

   Answer: A. 10%

   The 2017 classification defines a gingivitis case as bleeding on probing at 10% or more of sites; 10-30% is localised and over 30% is generalised. Below 10% with no other signs is gingival health.

3. Question 3Mucogingival Conditions and Acute Lesionsmedium

   For a single maxillary canine with RT1 recession and a thin gingival phenotype, which procedure gives the best root coverage outcome?

   1. AFree gingival graft as the only surgical procedure
   2. BApically repositioned full-thickness flap
   3. CExternal bevel gingivectomy and gingivoplasty
   4. DCoronally advanced flap with connective tissue graft
   Show answer and explanation▾

   Answer: D. Coronally advanced flap with connective tissue graft

   A coronally advanced flap with a subepithelial connective tissue graft is the reference standard for root coverage, especially with a thin phenotype. A free gingival graft increases keratinised tissue but gives less predictable coverage and poorer colour match.

4. Question 4Non-Surgical Therapy and Pharmacotherapymedium

   How does sub-antimicrobial dose doxycycline (20 mg twice daily) work as an adjunct in periodontitis?

   1. AIt inhibits matrix metalloproteinases
   2. BIt kills subgingival anaerobes
   3. CIt stimulates new cementum formation
   4. DIt increases salivary flow
   Show answer and explanation▾

   Answer: A. It inhibits matrix metalloproteinases

   At 20 mg twice daily, doxycycline acts as a host modulator by inhibiting collagenase (MMP) activity, without antibacterial effect. The dose is too low to kill subgingival bacteria.

5. Question 5Supportive Care, Infection Control and Ethicseasy

   A patient has completed active periodontal treatment for Stage III periodontitis. How often should supportive periodontal care be scheduled?

   1. AOnce every 2 years, if no bleeding
   2. BOnly when symptoms recur
   3. CEvery 3-12 months, based on risk
   4. DEvery 2 weeks indefinitely
   Show answer and explanation▾

   Answer: C. Every 3-12 months, based on risk

   The EFP S3 guideline recommends supportive care at intervals of 3 to at most 12 months, set by each patient's risk profile. Waiting for symptoms allows silent recurrence.

6. Question 6Peri-Implant Diseases and Implant Therapymedium

   After extraction of a maxillary premolar without ridge preservation, which change is greatest in the first year?

   1. AGain in vertical ridge height
   2. BLoss of buccolingual ridge width
   3. CLoss of palatal ridge height
   4. DExpansion of the buccal plate
   Show answer and explanation▾

   Answer: B. Loss of buccolingual ridge width

   Ridge width can fall by about half within 12 months, mostly from the buccal side and largely in the first 3 months. Horizontal loss exceeds vertical loss.

7. Question 7Periodontal Surgery and Regenerationhard

   A lower first molar has a class III furcation. The distal root has bone loss to the apex, but the mesial root has good support and the tooth is restorable. What is the most appropriate option?

   1. AGuided tissue regeneration of the class III furcation
   2. BImmediate extraction of the whole tooth and implant
   3. CEndodontics, then hemisection keeping the mesial root
   4. DSupragingival scaling and observation every 6 months
   Show answer and explanation▾

   Answer: C. Endodontics, then hemisection keeping the mesial root

   Hemisection keeps the well-supported mesial root as an abutment; endodontic treatment is done first. Regeneration of class III furcations is unpredictable, which rules out GTR.

8. Question 8Supportive Care, Infection Control and Ethicseasy

   Before periodontal surgery, which element is essential for valid informed consent?

   1. AA countersignature from the dental nurse present
   2. BFull payment of the treatment fee first
   3. CExplaining alternatives, including no treatment
   4. DConsent taken after sedation is given
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   Answer: C. Explaining alternatives, including no treatment

   Valid consent requires that the patient understands the nature, risks, benefits and alternatives, including no treatment, and agrees voluntarily while competent. Consent obtained after sedation is invalid.

9. Question 9Periodontal Anatomy, Microbiology and Host Responsemedium

   How does the junctional epithelium attach to the tooth surface?

   1. ADesmosomes between keratinised cells
   2. BHemidesmosomes and an internal basal lamina
   3. CSharpey fibres inserted into cementum
   4. DGap junctions with odontoblast processes
   Show answer and explanation▾

   Answer: B. Hemidesmosomes and an internal basal lamina

   Junctional epithelium attaches to enamel or cementum through an internal basal lamina and hemidesmosomes. Sharpey fibres are periodontal ligament fibres anchored in cementum and bone, not epithelial attachment.

10. Question 10Periodontal Surgery and Regenerationmedium

    Which intrabony defect morphology responds best to guided tissue regeneration?

    1. AShallow, wide one-wall defect
    2. BDeep, narrow three-wall defect
    3. CHorizontal bone loss
    4. DWide circumferential crater
    Show answer and explanation▾

    Answer: B. Deep, narrow three-wall defect

    Deep, narrow defects with three bony walls provide space and blood supply for regeneration and give the best results. Horizontal bone loss is not predictably regenerated.

11. Question 11Periodontal Surgery and Regenerationmedium

    Before crowning a fractured premolar with a subgingival margin, crown lengthening is planned. How much tooth should be left between the planned margin and the alveolar crest?

    1. AAbout 3 mm
    2. BAbout 0.5 mm
    3. CAbout 1 mm
    4. DAbout 6 mm
    Show answer and explanation▾

    Answer: A. About 3 mm

    Leaving about 3 mm from the restoration margin to the bone crest allows the supracrestal tissue attachment (about 2 mm) to re-form, plus a sulcus. Leaving only 1 mm invades the attachment and causes chronic inflammation.

12. Question 12Periodontal Surgery and Regenerationmedium

    During resective osseous surgery, what distinguishes ostectomy from osteoplasty?

    1. AOstectomy reshapes non-supporting bone
    2. BOsteoplasty removes supporting bone
    3. COstectomy removes supporting bone
    4. DThey are the same procedure
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    Answer: C. Ostectomy removes supporting bone

    Ostectomy removes bone that supports the tooth, while osteoplasty reshapes bone without removing supporting bone. Mixing them up leads to unintended attachment loss.

13. Question 13Periodontal-Systemic Interactionsmedium

    A patient on warfarin for atrial fibrillation has a stable INR of 2.6 checked yesterday and needs subgingival instrumentation. What is appropriate?

    1. AStop warfarin for 5 days first
    2. BProceed with local haemostatic measures
    3. CSwitch to heparin bridging before treatment
    4. DDefer until INR is below 1.5
    Show answer and explanation▾

    Answer: B. Proceed with local haemostatic measures

    Patients with a stable INR below 4 can usually have periodontal instrumentation without stopping warfarin, using local measures to control bleeding. Stopping anticoagulation risks thromboembolism.

14. Question 14Periodontal-Systemic Interactionsmedium

    A pregnant patient at 12 weeks has periodontitis with bleeding gums. When is non-surgical periodontal treatment best scheduled?

    1. AOnly after delivery
    2. BOnly in the first trimester
    3. CIn the second trimester
    4. DIn the last month of pregnancy
    Show answer and explanation▾

    Answer: C. In the second trimester

    Non-surgical periodontal therapy is safe in pregnancy and is best done in the second trimester, when the patient is most comfortable. Delaying all care until after delivery is unnecessary.

15. Question 15Supportive Care, Infection Control and Ethicsmedium

    Wrapped periodontal instruments are sterilised in a vacuum steam autoclave. Which cycle is standard for these instruments?

    1. A121 C for only 30 seconds
    2. B134-137 C for at least 3 minutes
    3. C100 C for at least 10 minutes
    4. D160 C for at least 3 minutes
    Show answer and explanation▾

    Answer: B. 134-137 C for at least 3 minutes

    Steam sterilisation at 134-137 C with a holding time of at least 3 minutes is the standard cycle for dental instruments. Boiling at 100 C does not sterilise, and 160 C is a dry-heat temperature needing much longer.

Last reviewed September 2026. Questions are original and written to the published exam blueprint; they are not taken from any real paper.