ABP Periodontal Anatomy 3 — Questions and Answers
Question 1: Which cells are primarily responsible for maintaining and remodeling the alveolar bone proper (bundle bone) adjacent to the PDL?
- Osteoclasts only
- Osteoblasts and osteoclasts (Correct answer)
- Cementoblasts
- Fibroblasts
Correct answer: Osteoblasts and osteoclasts
Alveolar bone remodeling is carried out by coordinated activity of osteoblasts (bone formation) and osteoclasts (bone resorption), regulated by local and systemic signals.
Question 2: The mucogingival junction (MGJ) in the maxillary anterior region is identified clinically by which characteristic?
- Color change from pale pink to darker red/pink alveolar mucosa (Correct answer)
- Depth of the gingival sulcus at that point
- Presence of stippling apical to that line
- Location of the cemento-enamel junction
Correct answer: Color change from pale pink to darker red/pink alveolar mucosa
The MGJ is recognized by a color change from the pale, stippled keratinized gingiva to the redder, non-keratinized, movable alveolar mucosa.
Question 3: Sharpey's fibers are the embedded portions of which periodontal structure?
- Gingival circular fibers
- PDL principal fibers (extrinsic fibers) (Correct answer)
- Junctional epithelium hemidesmosomes
- Cementum intrinsic fibers
Correct answer: PDL principal fibers (extrinsic fibers)
Sharpey's fibers are the mineralized ends of principal PDL collagen fiber bundles that insert into both cementum and alveolar bone proper.
Question 4: Which zone of the junctional epithelium directly contacts the tooth surface via hemidesmosomes and a basal lamina?
- Oral sulcular epithelium layer
- Inner layer facing the tooth (Correct answer)
- Outer layer facing connective tissue
- Stratum spinosum layer
Correct answer: Inner layer facing the tooth
The inner layer (dentally facing cells) of the junctional epithelium attaches to enamel, cementum, or dentin via hemidesmosomes and an internal basal lamina.
Question 5: Which artery is the primary blood supply to the buccal gingiva of the maxillary posterior teeth?
- Inferior alveolar artery
- Posterior superior alveolar artery (Correct answer)
- Greater palatine artery
- Facial artery
Correct answer: Posterior superior alveolar artery
The posterior superior alveolar artery (branch of the maxillary artery) supplies the buccal gingiva and alveolar mucosa of the maxillary posterior region.
Question 6: The lamina dura visible on periapical radiographs corresponds histologically to which structure?
- Cortical plate of alveolar housing
- Alveolar bone proper (cribriform plate/bundle bone) (Correct answer)
- Dense cementum layer
- Periodontal ligament space
Correct answer: Alveolar bone proper (cribriform plate/bundle bone)
The lamina dura is the radiodense line representing the alveolar bone proper (cribriform plate), which is perforated by canals transmitting vessels to the PDL.
Question 7: The average physiologic depth of the gingival sulcus in clinically healthy human gingiva (histologic measurement) is approximately:
- 0.5 mm
- 1.8 mm (Correct answer)
- 3.0 mm
- 4.5 mm
Correct answer: 1.8 mm
Histologic studies (Gargiulo et al. 1961) show the average sulcus depth is approximately 1.8 mm, though clinical probing values are often higher due to probe penetration.
ABP Periodontal Anatomy 3
Which cells are primarily responsible for maintaining and remodeling the alveolar bone proper (bundle bone) adjacent to the PDL?