MJDF Dental Anatomy & Physiology 2 — Questions and Answers
Question 1: Which salivary gland produces the most saliva in resting (unstimulated) conditions?
- Submandibular gland (Correct answer)
- Parotid gland
- Sublingual gland
- Minor salivary glands
Correct answer: Submandibular gland
The submandibular glands contribute approximately 65–70% of unstimulated saliva; the parotid gland dominates stimulated salivary flow, producing a serous secretion.
Question 2: What is the role of saliva in caries prevention?
- Buffering acids, antimicrobial proteins, remineralisation, lubrication, and pellicle formation (Correct answer)
- Producing fluoride naturally
- Breaking down dietary sugars
- Providing direct mechanical flushing only
Correct answer: Buffering acids, antimicrobial proteins, remineralisation, lubrication, and pellicle formation
Saliva prevents caries through bicarbonate buffering of plaque acids, antimicrobial proteins (lactoferrin, lysozyme, IgA), calcium and phosphate for remineralisation, and forming the protective acquired pellicle.
Question 3: Where does Wharton's duct open in the mouth?
- Sublingual papilla at the base of the frenulum (lingual to lower central incisors) (Correct answer)
- Parotid papilla opposite upper second molar
- Hard palate
- Floor of mouth laterally
Correct answer: Sublingual papilla at the base of the frenulum (lingual to lower central incisors)
Wharton's duct (submandibular duct) opens at the sublingual papilla (caruncle) adjacent to the lingual frenum on the floor of the mouth.
Question 4: What is the embryological origin of enamel?
- Oral ectoderm (dental lamina and enamel organ) (Correct answer)
- Neural crest cells
- Mesoderm
- Endoderm
Correct answer: Oral ectoderm (dental lamina and enamel organ)
Enamel is the only dental tissue derived from oral ectoderm; ameloblasts originate from the inner enamel epithelium of the enamel organ, which develops from the dental lamina.
Question 5: Which nerve supplies sensory innervation to the mandibular first molar?
- Inferior alveolar nerve (branch of V3) (Correct answer)
- Mental nerve
- Lingual nerve
- Long buccal nerve
Correct answer: Inferior alveolar nerve (branch of V3)
The inferior alveolar nerve (a branch of V3, mandibular division of trigeminal) provides sensory innervation to all mandibular posterior teeth via the mandibular canal.
Question 6: What is the width of the PDL space in a healthy adult tooth radiographically?
- 0.15–0.38 mm (Correct answer)
- 0.5–1.0 mm
- 1.0–2.0 mm
- 0.05–0.1 mm
Correct answer: 0.15–0.38 mm
The normal PDL space appears as a thin radiolucent line measuring 0.15–0.38 mm; widening indicates pathology (occlusal trauma, inflammation) and narrowing suggests ankylosis.
MJDF Dental Anatomy & Physiology 2
Which salivary gland produces the most saliva in resting (unstimulated) conditions?