100+ Free ORE Part 1 Practice Questions

Explanation: The long buccal nerve, a branch of the anterior division of the mandibular nerve (CN V3), supplies the buccal gingivae adjacent to the mandibular molars. This is why a standard inferior alveolar nerve block does not anaesthetise this soft tissue and a separate long buccal infiltration is often required for molar extractions.

Explanation: The maxillary division of the trigeminal nerve leaves the middle cranial fossa through the foramen rotundum to enter the pterygopalatine fossa. From there it continues as the infraorbital nerve. This is a core piece of head and neck anatomy underpinning maxillary local anaesthesia.

Explanation: Odontoblasts differentiate from the dental papilla and secrete predentine which mineralises to dentine; they retain a process within the dentinal tubule throughout life. Ameloblasts, by contrast, form enamel and are lost after eruption, which is why enamel cannot be regenerated.

Explanation: The facial nerve provides motor supply to the muscles of facial expression, including frontalis (forehead) and orbicularis oculi (eye closure). It passes through the parotid gland, so injury here produces a lower motor neurone facial palsy affecting the whole side of the face.

Explanation: The lateral pterygoid muscles, acting bilaterally, protrude the mandible by pulling the condyles and articular discs forward down the articular eminence. Unilateral contraction produces contralateral lateral movement, which is the basis of clinical mandibular movement testing.

Explanation: The tip (apex) of the tongue drains bilaterally to the submental lymph nodes before continuing to the deep cervical chain. Knowing the orderly drainage pathways is important for assessing the spread of oral squamous cell carcinoma and infection.

Explanation: The parotid gland is the largest major salivary gland and produces an almost entirely serous (watery, enzyme-rich) secretion via Stensen's duct opposite the maxillary second molar. Its serous nature is relevant to mumps and to sialography findings.

Explanation: Saliva is supersaturated with calcium and phosphate and contains bicarbonate buffers that neutralise plaque acids, raising pH above the critical level and driving remineralisation of early enamel lesions. Reduced salivary flow (xerostomia) therefore substantially increases caries risk.

Explanation: Vitamin C (ascorbic acid) is an essential cofactor for prolyl and lysyl hydroxylase in collagen synthesis. Deficiency impairs collagen cross-linking, producing the spongy, bleeding gingivae, poor wound healing, and perifollicular haemorrhages of scurvy.

Explanation: Enamel hydroxyapatite begins to dissolve when plaque pH falls below approximately 5.5, the critical pH at which the surrounding fluid becomes unsaturated with respect to hydroxyapatite. Frequent sugar intake repeatedly drops pH below this threshold, driving net demineralisation.