MFDS Oral Surgery

Question 1

A patient presents for extraction of a lower third molar. The radiograph shows the roots in close proximity to the inferior alveolar canal. Which sign on the radiograph is the MOST reliable indicator of a true intimate relationship between the tooth roots and the inferior alveolar nerve?

Accepted Answer

Loss of the lamina dura of the canal wall where the root crosses

Answer

Loss (interruption) of the white corticated line of the inferior alveolar canal where the root crosses is the most reliable radiographic sign of a true intimate relationship. Other signs include darkening (increased radiolucency) of the root, deflection of the canal, and narrowing of the canal, but loss of the cortical outline is considered the strongest predictor of nerve injury risk.

Question 2

During surgical removal of an upper first premolar, the root fractures and the apical fragment is displaced into the maxillary sinus. What is the most appropriate initial management?

Accepted Answer

Inform the patient, prescribe antibiotics and a nasal decongestant, and arrange a referral for surgical retrieval

Answer

A root fragment displaced into the maxillary sinus should not be retrieved via the socket as this may enlarge the oroantral communication. The patient should be informed, prescribed antibiotics (amoxicillin) and a nasal decongestant (ephedrine nasal drops), given sinus precautions, and referred for elective surgical retrieval, usually via a Caldwell-Luc approach under general anaesthesia.

Question 3

What is the most appropriate local anaesthetic technique for extraction of a lower first molar in an adult patient?

Accepted Answer

Inferior alveolar nerve block supplemented with long buccal nerve infiltration

Answer

The lower first molar is innervated by the inferior alveolar nerve (pulpal and lingual soft tissue) and the long buccal nerve (buccal soft tissue). An inferior alveolar nerve block anaesthetises the tooth and lingual tissues, while a supplementary long buccal infiltration anaesthetises the buccal gingivae. In some patients, articaine infiltration alone may suffice due to its superior bone penetration, but the IANB plus long buccal is the standard technique.

Question 4

A patient develops a dry socket (alveolar osteitis) three days after extraction of a lower wisdom tooth. Which of the following best describes the pathogenesis and management?

Accepted Answer

Premature loss of the blood clot with exposed bone causing severe pain, managed with irrigation and placement of a sedative dressing such as Alvogyl

Answer

Dry socket results from premature lysis of the blood clot, possibly due to excessive fibrinolysis activated by bacterial enzymes. The exposed alveolar bone causes severe, throbbing pain radiating to the ear, with halitosis and a foul taste. Management involves gentle irrigation with warm saline to remove debris and placement of a sedative/antiseptic dressing (e.g., Alvogyl containing butamben, iodoform, and eugenol). Systemic antibiotics are not indicated unless there is spreading infection.

Question 5

Which of the following is an absolute contraindication to dental extractions without specialist consultation?

Accepted Answer

Patient currently taking therapeutic doses of warfarin with INR of 3.8

Answer

An INR of 3.8 exceeds the safe threshold for dental extractions in primary care (generally INR should be ≤4.0 for simple extractions, but ideally ≤3.5 with local haemostatic measures). At this level, the bleeding risk is significantly elevated and specialist consultation is warranted to balance the risks of haemorrhage against thromboembolism from anticoagulant modification. The other conditions, when well controlled, are managed routinely in general practice.

MFDS Part 1 Practice Test

MFDS Part 1 Practice Test

MFDS Oral Surgery