AGD Periodontics and Gum Health 5 — Questions and Answers
Question 1: Which growth factor, released from platelet-rich plasma (PRP), is MOST important for stimulating periodontal ligament cell proliferation?
- Transforming growth factor-β (TGF-β)
- Platelet-derived growth factor (PDGF) (Correct answer)
- Vascular endothelial growth factor (VEGF)
- Fibroblast growth factor (FGF)
Correct answer: Platelet-derived growth factor (PDGF)
PDGF is the primary mitogen released from platelets that stimulates PDL fibroblast proliferation and wound healing in periodontal regeneration.
Question 2: The 'critical probing depth' concept in periodontal maintenance suggests that sites with probing depths below this threshold will GAIN attachment after SRP, while deeper sites will lose attachment. This threshold is approximately:
- 1–2 mm
- 2–3 mm (Correct answer)
- 4–5 mm
- 6–7 mm
Correct answer: 2–3 mm
Research by Lindhe and others identified approximately 2–3 mm as the critical depth where shallow sites tend to lose and deeper sites tend to gain attachment after SRP.
Question 3: Emdogain (enamel matrix derivative) promotes periodontal regeneration primarily by:
- Acting as a barrier membrane
- Mimicking Hertwig's epithelial root sheath proteins to stimulate cementogenesis and new attachment (Correct answer)
- Delivering antibiotic locally to the defect
- Providing an osteoconductive scaffold
Correct answer: Mimicking Hertwig's epithelial root sheath proteins to stimulate cementogenesis and new attachment
Emdogain's amelogenin proteins recapitulate root development signals, inducing new cementum, periodontal ligament, and alveolar bone formation.
Question 4: A patient undergoing periodontal maintenance should ideally be recalled at what interval to prevent disease recurrence in susceptible individuals?
- Every 6 months
- Every 3 months (Correct answer)
- Every 12 months
- Every 1 month
Correct answer: Every 3 months
Evidence supports a 3-month recall interval for periodontal maintenance patients, as subgingival pathogen repopulation peaks by approximately 9–11 weeks post-debridement.
Question 5: Which type of bone graft material carries the HIGHEST risk of disease transmission but also has the highest osteogenic potential?
- Alloplast (synthetic)
- Autograft (Correct answer)
- Allograft (DFDBA)
- Xenograft (bovine)
Correct answer: Autograft
Autografts contain living osteogenic cells making them the gold standard for osteogenic potential, but autologous harvesting carries surgical morbidity rather than disease transmission risk; however, among graft types, they uniquely provide live cells.
Question 6: In the Periodontal Risk Assessment (PRA) model, which factor is NOT used to calculate a patient's risk category?
- Percentage of bleeding on probing
- Number of sites with probing depth ≥5 mm
- Patient's age and bone loss ratio
- Patient's income level (Correct answer)
Correct answer: Patient's income level
The Lang and Tonetti PRA model uses BOP%, residual pockets, tooth loss, bone loss/age ratio, systemic conditions, and smoking — not socioeconomic status.
Question 7: Which suture technique is preferred for closing papillae after interproximal bone grafting to maximize primary closure?
- Simple interrupted suture
- Vertical mattress suture (Correct answer)
- Horizontal mattress suture
- Continuous sling suture
Correct answer: Vertical mattress suture
Vertical mattress sutures evert wound edges and provide tension-free primary closure of papillae over graft material, reducing membrane/graft exposure.
AGD Periodontics and Gum Health 5
Which growth factor, released from platelet-rich plasma (PRP), is MOST important for stimulating periodontal ligament cell proliferation?