DDS Dental Anatomy and Histology 2 — Questions and Answers
Question 1: The gubernacular canal in the jaw bone transmits which structure during tooth eruption?
- Blood vessels supplying the dental follicle
- The gubernacular cord connecting follicle to oral epithelium (Correct answer)
- Nerve fibers of the inferior alveolar nerve
- Lymphatics draining the developing tooth
Correct answer: The gubernacular cord connecting follicle to oral epithelium
The gubernacular cord, a fibrous band connecting the dental follicle to the overlying oral epithelium, passes through the gubernacular canal to guide eruption.
Question 2: Which cell is responsible for the formation of the dental lamina?
- Ectomesenchymal cells
- Oral epithelial cells (Correct answer)
- Neural crest cells
- Endodermal cells
Correct answer: Oral epithelial cells
The dental lamina arises from proliferation of the oral (ectoderm-derived) epithelium as it invaginates into the underlying ectomesenchyme.
Question 3: Hertwig's epithelial root sheath is derived from which two epithelial layers?
- Outer enamel epithelium and stellate reticulum
- Inner enamel epithelium and outer enamel epithelium (Correct answer)
- Stratum intermedium and stellate reticulum
- Inner enamel epithelium and stratum intermedium
Correct answer: Inner enamel epithelium and outer enamel epithelium
Hertwig's epithelial root sheath is a double layer formed by the fusion of the inner and outer enamel epithelium at the cervical loop after crown formation.
Question 4: Rests of Malassez are remnants of which structure found in the periodontal ligament?
- Dental lamina
- Successional lamina
- Hertwig's epithelial root sheath (Correct answer)
- Reduced enamel epithelium
Correct answer: Hertwig's epithelial root sheath
After root formation, Hertwig's sheath disintegrates and leaves behind epithelial cell clusters called rests of Malassez within the PDL.
Question 5: The principal fibers of the periodontal ligament that run from the alveolar crest obliquely to insert into the root are called:
- Horizontal fibers
- Oblique fibers (Correct answer)
- Alveolar crest fibers
- Apical fibers
Correct answer: Oblique fibers
Oblique fibers are the most numerous PDL principal fibers, running obliquely from alveolar bone to cementum to resist masticatory forces.
Question 6: Which gland produces the largest volume of saliva under resting (unstimulated) conditions?
- Parotid gland
- Sublingual gland
- Submandibular gland (Correct answer)
- Minor salivary glands
Correct answer: Submandibular gland
The submandibular gland contributes approximately 60–65% of unstimulated salivary flow, making it the dominant resting-state salivary gland.
DDS Dental Anatomy and Histology 2
The gubernacular canal in the jaw bone transmits which structure during tooth eruption?