ABP Periodontal Anatomy 2 — Questions and Answers
Question 1: Which fiber group of the periodontal ligament runs from the alveolar crest obliquely to the cementum in an apical direction?
- Horizontal fibers
- Oblique fibers (Correct answer)
- Alveolar crest fibers
- Apical fibers
Correct answer: Oblique fibers
Oblique fibers are the most numerous PDL fibers and run from the alveolar bone in a coronal direction to insert into cementum, resisting occlusal forces.
Question 2: The stippling observed on healthy attached gingiva is most closely associated with which histological feature?
- Dense collagen bundles in the lamina propria
- Rete peg interdigitation with connective tissue (Correct answer)
- Keratinized epithelium surface texture
- Melanin pigmentation in the basal layer
Correct answer: Rete peg interdigitation with connective tissue
Gingival stippling results from interdigitation of epithelial rete pegs with connective tissue papillae, creating surface indentations visible clinically.
Question 3: Cementum that is deposited throughout life on the root surface in an appositional manner and contains entrapped cementoblasts is called:
- Primary acellular cementum
- Secondary cellular cementum (Correct answer)
- Intermediate cementum
- Afibrillar cementum
Correct answer: Secondary cellular cementum
Secondary cellular (or cellular intrinsic fiber) cementum is formed after tooth eruption, contains cementocytes, and is found primarily in the apical third and furcation areas.
Question 4: The width of the attached gingiva is typically greatest in which region of the dentition?
- Mandibular first molar buccal
- Maxillary anterior facial (Correct answer)
- Mandibular anterior lingual
- Maxillary posterior palatal
Correct answer: Maxillary anterior facial
The attached gingiva is widest in the maxillary anterior facial region (average 3.5–4.5 mm) and narrowest at the mandibular first premolar buccal.
Question 5: Which landmark defines the base of the gingival sulcus histologically?
- Alveolar crest
- Coronal extent of the junctional epithelium (Correct answer)
- Mucogingival junction
- Cementoenamel junction
Correct answer: Coronal extent of the junctional epithelium
The base of the gingival sulcus is formed by the most coronal cells of the junctional epithelium, which attaches to the tooth via hemidesmosomes.
Question 6: In the periodontium, the transseptal fiber group is classified as part of which structure?
- Periodontal ligament proper
- Supracrestal/supraalveolar gingival fibers (Correct answer)
- Alveolar bone periosteum
- Circular ligament fibers
Correct answer: Supracrestal/supraalveolar gingival fibers
Transseptal fibers are classified as supraalveolar (gingival) fibers that run interproximally from the cementum of one tooth over the alveolar crest to the cementum of the adjacent tooth.
Question 7: The biologic width refers to the combined dimension of which two structures?
- Gingival sulcus depth and junctional epithelium
- Junctional epithelium and supracrestal connective tissue attachment (Correct answer)
- Attached gingiva and alveolar mucosa
- Cementum thickness and PDL space
Correct answer: Junctional epithelium and supracrestal connective tissue attachment
Biologic width (Gargiulo et al.) averages approximately 2.04 mm and consists of the junctional epithelium (~0.97 mm) plus the supracrestal connective tissue attachment (~1.07 mm).
ABP Periodontal Anatomy 2
Which fiber group of the periodontal ligament runs from the alveolar crest obliquely to the cementum in an apical direction?