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Periodontics · patient case with 5 questions

Advanced Periodontitis

demo: 48-year-old male

chief: “My teeth are moving and I have gaps that were never there.”

history: Type 2 diabetes, HbA1c 8.4%. Smokes 15 cigarettes per day.

meds: Metformin

findings: Probing depths 7–10 mm generalized. Interdental clinical attachment loss extending beyond the middle third of the root at more than five teeth. Class II furcations at #3 and #14, tooth mobility degree 2, pathologic migration with flaring of the maxillary incisors, 18 remaining teeth. Radiographic bone loss has advanced 3 mm in the last 4 years.

Question 1

How is this periodontal case classified?

  1. Stage II, Grade C
  2. Stage IV, Grade A
  3. Stage III, Grade B
  4. Stage IV, Grade C
Show answer and explanation

Correct answer: D. Stage IV, Grade C

  • A. Stage II involves attachment loss confined to the coronal third with maximum probing depths around 5 mm.
  • B. Grade A denotes slow progression with no bone loss over 5 years and no risk modifiers — the opposite of this patient.
  • C. Stage III lacks the masticatory dysfunction and drifting that push this case to Stage IV, and Grade B would require slower progression, lighter smoking, and better glycemic control.
  • D. Correct. Stage IV is established by the need for complex rehabilitation — secondary occlusal trauma with mobility degree ≥2, bite collapse and flaring, and fewer than 20 remaining teeth. Grade C follows from ≥2 mm bone loss over 5 years, smoking ≥10 cigarettes/day, and HbA1c ≥7.0%.

Note: Staging is set by severity and complexity; grading is set by rate of progression plus the risk modifiers of smoking and diabetes. Grade is the part that moves with the patient's habits.

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Question 2

A 6 mm infrabony defect is found distal to tooth #7, which is vital with no history of trauma and no vertical fracture. Which treatment is most effective?

  1. Guided tissue regeneration
  2. Gingivectomy
  3. Systemic antibiotics alone
  4. Osseous resective surgery
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Correct answer: A. Guided tissue regeneration

  • A. Correct. A narrow, contained vertical (infrabony) defect is the classic indication for GTR. A barrier membrane excludes epithelium and gingival connective tissue so that PDL and bone cells repopulate the defect.
  • B. Gingivectomy removes soft tissue only and is contraindicated where there is an infrabony component or inadequate keratinized tissue.
  • C. Antibiotics are an adjunct; they cannot regenerate lost attachment.
  • D. Osseous resection would sacrifice supporting bone in an esthetic anterior site and is better suited to shallow horizontal defects.

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Question 3

Guided tissue regeneration is best indicated for which bone loss pattern and furcation grade?

  1. Class IV furcation with complete recession
  2. Vertical (infrabony) bone loss and Class II furcation involvement
  3. Class III through-and-through furcation
  4. Generalized horizontal bone loss
Show answer and explanation

Correct answer: B. Vertical (infrabony) bone loss and Class II furcation involvement

  • A. Class IV furcations, fully open and visible, are the least favorable of all for regeneration.
  • B. Correct. Vertical defects with retained bony walls, and Class II furcations where the probe only partially enters, provide the containment a membrane needs to work.
  • C. A through-and-through Class III defect cannot be predictably regenerated.
  • D. Horizontal bone loss offers no space for regeneration to occur and responds poorly to GTR.

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Question 4

The primary treatment objective of guided tissue regeneration is:

  1. Coronal repopulation of the root surface by periodontal ligament cells
  2. Elimination of the pocket by apical repositioning of the gingival margin
  3. Sclerosis of the defect with dense connective tissue
  4. Rapid coverage of the defect by junctional epithelium
Show answer and explanation

Correct answer: A. Coronal repopulation of the root surface by periodontal ligament cells

  • A. Correct. The membrane excludes the fast-migrating epithelial and gingival connective tissue cells so that PDL cells, which are slower, can move coronally and regenerate cementum, PDL, and bone with new Sharpey's fiber insertion.
  • B. Apical repositioning is the goal of resective surgery, not regeneration.
  • C. Fibrous scarring is repair, not the functional periodontal attachment GTR aims for.
  • D. Epithelial downgrowth is exactly what the barrier is designed to prevent — it produces a long junctional epithelium, which is repair, not regeneration.

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Question 5

Which grafting material is preferred when the objective is to stimulate new bone formation rather than simply to fill space?

  1. FDBA, because its mineral content makes it osteoinductive
  2. Hydroxyapatite, because it is osteogenic
  3. Autogenous cortical block, because it is purely osteoconductive
  4. DFDBA, because demineralization exposes bone morphogenetic proteins and makes it osteoinductive
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Correct answer: D. DFDBA, because demineralization exposes bone morphogenetic proteins and makes it osteoinductive

  • A. FDBA retains its mineral and is osteoconductive; it provides a sturdy scaffold and structural support, not induction.
  • B. Synthetic hydroxyapatite is osteoconductive only — it is an alloplast with no living cells and no inductive proteins.
  • C. Autogenous bone is the only material that is genuinely osteogenic, because it carries viable cells; describing it as purely osteoconductive understates it.
  • D. Correct. Demineralized freeze-dried bone allograft exposes BMPs in the matrix, giving it osteoinductive potential — it recruits and differentiates host cells into bone-forming cells.

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