NBDHE Periodontal Assessment and Treatment 2 — Questions and Answers

Question 1: According to the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases, Stage III periodontitis is characterized by:

Tooth loss due to periodontitis, bone loss to the middle or apical third of the root, or furcation class II or III involvement (Correct answer)
Mild bone loss with probing depths ≤4 mm
Bone loss limited to the coronal third with no furcation involvement
Generalized attachment loss with severe systemic complications

Correct answer: Tooth loss due to periodontitis, bone loss to the middle or apical third of the root, or furcation class II or III involvement

Stage III periodontitis is characterized by tooth loss attributable to periodontitis, bone loss extending to the middle or apical third of the root, and/or furcation class II or III defects, distinguishing it from less severe stages.

The 2017 classification system stages periodontitis I–IV based on severity and complexity: Stage I — mild, CAL 1–2 mm; Stage II — moderate, CAL 3–4 mm; Stage III — severe with tooth loss potential (bone loss to middle/apical third, ≥20% bone loss, furcation Class II/III, vertical bone loss ≥3 mm, probing depths ≥6 mm); Stage IV — very severe with masticatory dysfunction (extensive tooth loss, bite collapse, less than 20 remaining teeth, severe ridge deficiency). Grade (A, B, C) overlays on Stage to reflect rate of progression, risk factors, and systemic impact. This replaced the earlier chronic/aggressive classification.

Question 2: Which type of bone defect is characterized by bone loss on one root surface only, maintaining normal height on adjacent roots?

One-wall (hemiseptal) defect (Correct answer)
Two-wall defect
Three-wall defect (intrabony)
Cratering (two-wall interdental)

Correct answer: One-wall (hemiseptal) defect

A one-wall (hemiseptal) defect has bone remaining on only one side of the defect — the least favorable for regenerative treatment as it provides minimal bony walls for clot stabilization.

Periodontal bone defects are classified by the number of remaining bony walls: (1) One-wall — one bony wall remains (typically the lingual or buccal wall); common in narrow interproximal areas; poorest prognosis for regeneration; (2) Two-wall — two walls remain; includes the common crater defect (two walls = buccal and lingual); moderate regenerative potential; (3) Three-wall — surrounded by bone on three sides; best prognosis for regeneration as walls provide scaffolding for blood clot; (4) Circumferential — bone loss around entire root circumference. Cone-beam CT or surgical exploration definitively classifies defect morphology; radiographic diagnosis may underestimate defect extent.

Question 3: During a periodontal chart, the dental hygienist records a probing depth of 4 mm at the midbuccal of tooth #19 with 2 mm of recession. The clinical attachment level (CAL) is:

6 mm (Correct answer)
2 mm
4 mm
8 mm

Correct answer: 6 mm

CAL = probing depth + recession (when the gingival margin is apical to the CEJ): 4 mm + 2 mm = 6 mm clinical attachment loss.

Clinical attachment level (CAL) measures the distance from the cementoenamel junction (CEJ) to the base of the pocket, regardless of gingival margin position. When the gingival margin is at the CEJ: CAL = probing depth. When the gingival margin is apical to the CEJ (recession): CAL = probing depth + recession. When the gingival margin is coronal to the CEJ (pseudo-pocket): CAL = probing depth − the distance from CEJ to gingival margin. CAL is the gold standard for assessing actual periodontal destruction and is used for staging periodontitis, monitoring progression, and evaluating treatment outcomes. Probing depth alone can be misleading if accompanied by recession or hyperplastic gingiva.

Question 4: Scaling and root planing (SRP) is classified as which level of periodontal therapy?

Phase I (cause-related/non-surgical) therapy (Correct answer)
Phase II (surgical) therapy
Phase III (restorative) therapy
Phase IV (maintenance) therapy

Correct answer: Phase I (cause-related/non-surgical) therapy

SRP is the cornerstone of Phase I (cause-related/initial) periodontal therapy, aimed at disrupting and removing subgingival bacterial biofilm and calculus deposits before any surgical decisions are made.

Periodontal therapy is divided into four phases: Phase I (cause-related/non-surgical) — elimination of etiological factors: SRP, oral hygiene instruction, caries control, tooth extraction; Phase II (surgical) — periodontal surgery where Phase I has been inadequate: osseous surgery, guided tissue regeneration, crown lengthening; Phase III (restorative) — final restorations after periodontal stability; Phase IV (supportive periodontal therapy/maintenance) — recall visits every 3–4 months with re-assessment. SRP effectiveness is assessed at a re-evaluation 4–8 weeks after completion; sites with persistent deep pockets (≥5 mm) and bleeding may be referred for surgical consideration.

Question 5: Which systemic condition is most strongly associated with necrotizing periodontal diseases (NPD)?

HIV infection/immunosuppression and malnutrition/stress (Correct answer)
Type 2 diabetes mellitus
Osteoporosis
Cardiovascular disease

Correct answer: HIV infection/immunosuppression and malnutrition/stress

Necrotizing periodontal diseases (NUG, NUP, necrotizing stomatitis) are strongly associated with HIV infection and other immunosuppressive states, as well as severe malnutrition and stress.

Necrotizing ulcerative gingivitis (NUG) and necrotizing ulcerative periodontitis (NUP) are classified separately in the 2017 classification as necrotizing periodontal diseases. They are characterized by: necrosis of interdental papillae with 'punched-out' ulcerations covered by gray pseudomembrane, pain, bleeding, and fetid breath. Strongly associated with: HIV/AIDS (especially CD4 counts <200), severe systemic immunosuppression, severe malnutrition (Sub-Saharan Africa — noma/cancrum oris in children), psychosocial stress, and smoking. Treatment: local debridement, antimicrobials (metronidazole 250 mg TID × 7 days), chlorhexidine rinse, pain management, systemic management of underlying condition.

Question 6: Chlorhexidine gluconate 0.12% mouthrinse is used as an adjunct in periodontal therapy primarily because of its:

Broad-spectrum antimicrobial action and substantivity (prolonged binding to oral tissues) (Correct answer)
Fluoride content for caries prevention
Anti-inflammatory properties comparable to NSAIDs
Ability to remove calculus deposits

Correct answer: Broad-spectrum antimicrobial action and substantivity (prolonged binding to oral tissues)

Chlorhexidine's efficacy as a chemical plaque control agent is due to its cationic nature (binds to negatively charged bacterial surfaces) and substantivity — it binds to oral mucosa and is released over 8–12 hours, providing prolonged antimicrobial activity.

Chlorhexidine gluconate is a bisbiguanide with broad-spectrum bactericidal activity against gram-positive and gram-negative organisms, yeasts, and some viruses. Its key property is substantivity: the cationic molecule binds electrostatically to negatively charged oral surfaces (mucosa, teeth, pellicle) and is released slowly over 8–12 hours, maintaining inhibitory concentrations. The 0.12% concentration (Peridex, PerioGard) reduces plaque and gingivitis by ~60% when used twice daily as an adjunct to mechanical debridement. Side effects include tooth and restoration staining (tannic acid interaction), altered taste, and potential for resistant microorganism selection. It is not absorbed systemically in significant amounts.

NBDHE Periodontal Assessment and Treatment 2

According to the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases, Stage III periodontitis is characterized by: