DDS Trivia 2 — Questions and Answers
Question 1: Which cranial nerve is responsible for the general sensory innervation of the teeth and gums?
- Facial nerve (CN VII)
- Trigeminal nerve (CN V) (Correct answer)
- Glossopharyngeal nerve (CN IX)
- Hypoglossal nerve (CN XII)
Correct answer: Trigeminal nerve (CN V)
The trigeminal nerve (CN V) provides the primary sensory innervation to the teeth, periodontal ligament, and gingiva via its maxillary and mandibular divisions.
Question 2: What is the hardest substance in the human body?
- Dentin
- Cementum
- Enamel (Correct answer)
- Cortical bone
Correct answer: Enamel
Dental enamel is the hardest biological material in the human body, composed of approximately 96% hydroxyapatite mineral by weight.
Question 3: Which teeth are most commonly affected by pericoronitis?
- Maxillary first molars
- Mandibular second premolars
- Maxillary canines
- Mandibular third molars (Correct answer)
Correct answer: Mandibular third molars
Pericoronitis most commonly affects partially erupted mandibular third molars (wisdom teeth), where the overlying gingival flap traps bacteria.
Question 4: The 'rule of 1s' in local anesthesia refers to which landmark for inferior alveolar nerve blocks?
- 1 cm above the occlusal plane of the mandibular molars (Correct answer)
- 1 mm anterior to the pterygomandibular raphe
- 1 cm distal to the last mandibular molar
- 1 mm below the coronoid notch
Correct answer: 1 cm above the occlusal plane of the mandibular molars
The target for the inferior alveolar nerve block is approximately 1 cm (or one fingerbreadth) above the occlusal plane of the mandibular molars at the medial ramus.
Question 5: Which enzyme in saliva initiates carbohydrate digestion in the oral cavity?
- Lingual lipase
- Salivary amylase (ptyalin) (Correct answer)
- Lysozyme
- Carbonic anhydrase
Correct answer: Salivary amylase (ptyalin)
Salivary amylase (ptyalin) begins starch digestion in the mouth by cleaving alpha-1,4 glycosidic bonds in polysaccharides.
Question 6: What is the approximate pH at which hydroxyapatite in enamel begins to dissolve (critical pH)?
- 6.8
- 6.2
- 5.5 (Correct answer)
- 4.5
Correct answer: 5.5
The critical pH for enamel dissolution is approximately 5.5; below this level, the oral environment becomes undersaturated with respect to hydroxyapatite and demineralization occurs.
Question 7: Which cell type is primarily responsible for dentinogenesis?
- Ameloblasts
- Odontoblasts (Correct answer)
- Cementoblasts
- Fibroblasts
Correct answer: Odontoblasts
Odontoblasts, derived from neural crest cells, are responsible for producing predentin which subsequently mineralizes to form dentin throughout life.
DDS Trivia 2
Which cranial nerve is responsible for the general sensory innervation of the teeth and gums?