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MDCN Dental Assessment study materials
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MDCN Dental Assessment practice questions

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Question 1Dental Surgery

A patient attends for extraction of an upper first molar. Which local anaesthetic block is most appropriate for achieving pulpal anaesthesia of that tooth?

  1. Mental nerve block
  2. Inferior alveolar nerve block
  3. Greater palatine nerve block
  4. Posterior superior alveolar nerve block Correct answer.

Explanation

The posterior superior alveolar nerve supplies the pulps of the maxillary molars, so a PSA block provides pulpal anaesthesia for an upper first molar. Buccal infiltration is often used as an adjunct, but the PSA block is the targeted nerve block for these teeth.

Question 2Dental Surgery

During a mandibular third molar extraction, which anatomical structure lies closest to the roots and must be assessed on the pre-operative radiograph?

  1. Zygomatic process
  2. Incisive canal
  3. Greater palatine foramen
  4. Inferior alveolar canal Correct answer.

Explanation

The inferior alveolar canal runs through the mandible close to the apices of the lower third molar and carries the inferior alveolar nerve. Radiographic assessment of its proximity guides surgical technique and consent for nerve injury risk.

Question 3Dental Surgery

Which instrument is designed specifically for elevating the tooth from its socket during a routine extraction?

  1. Surgical curette
  2. Warwick James elevator Correct answer.
  3. Coupland elevator
  4. Dental mirror

Explanation

The Warwick James elevator is a fine, curved instrument used to sever the periodontal ligament and elevate the tooth from its socket. It applies controlled force to loosen the tooth before forceps are used.

Question 4Dental Surgery

A patient with a history of infective endocarditis undergoing a dental extraction should be offered antibiotic prophylaxis. Which regimen is standard for a patient with no penicillin allergy?

  1. Amoxicillin 2 g orally one hour before the procedure Correct answer.
  2. Erythromycin 500 mg two hours after the procedure
  3. Metronidazole 400 mg one hour before the procedure
  4. Amoxicillin 500 mg three times daily for five days after the procedure

Explanation

Current guidance recommends a single 2 g oral dose of amoxicillin taken one hour before the procedure for patients at high risk of infective endocarditis with no penicillin allergy. A single pre-procedural dose achieves adequate serum levels at the time of bacteraemia.

Question 5Dental Surgery

Which radiograph is the standard first-line imaging choice for assessing a single carious lesion in a posterior tooth?

  1. Cephalometric radiograph
  2. Panoramic radiograph
  3. Lateral skull radiograph
  4. Bitewing radiograph Correct answer.

Explanation

Bitewing radiographs show the crowns of both upper and lower posterior teeth in occlusion and are the standard first-line image for detecting interproximal caries. They provide high-resolution detail of the coronal tooth structure.

Question 6Dental Surgery

Which nerve block is used to anaesthetise the anterior two-thirds of the tongue for a surgical procedure?

  1. Long buccal nerve block
  2. Inferior alveolar nerve block
  3. Greater palatine nerve block
  4. Lingual nerve block Correct answer.

Explanation

The lingual nerve supplies general sensation to the anterior two-thirds of the tongue, so a lingual nerve block is required to anaesthetise this area. It is often performed together with an inferior alveolar nerve block.

Question 7Dental Surgery

Which of the following is a recognised local complication of a mandibular third molar extraction?

  1. Migraine
  2. Otitis media
  3. Conjunctivitis
  4. Dry socket Correct answer.

Explanation

Dry socket, or alveolar osteitis, is a well-recognised local complication following extraction of a mandibular third molar. It presents with severe pain and an empty socket a few days after surgery.

Question 8Dental Surgery

Which suture material is most appropriate for closing a mucosal flap after a surgical extraction when the suture will be removed in one week?

  1. Catgut
  2. Polydioxanone (PDS)
  3. Silk Correct answer.
  4. Polyglactin 910 (Vicryl)

Explanation

Silk is a non-resorbable braided suture commonly used for mucosal closure when the sutures will be removed at one week. Its handling characteristics and knot security make it suitable for short-term intraoral closure.

Question 9Dental Surgery

A patient reports a sudden onset of severe pain and swelling in the submandibular region with difficulty swallowing. Which condition should be suspected first?

  1. Temporomandibular joint disorder
  2. Dental erosion
  3. Ludwig's angina Correct answer.
  4. Trigeminal neuralgia

Explanation

Bilateral submandibular swelling with difficulty swallowing and systemic symptoms suggests Ludwig's angina, a rapidly spreading cellulitis of the submandibular and sublingual spaces. It is a life-threatening emergency requiring urgent airway assessment and intravenous antibiotics.

Question 10Dental Surgery

A patient with a known penicillin allergy requires antibiotic cover for a dental extraction. Which agent is the recommended alternative?

  1. Cephalexin 1 g one hour before the procedure
  2. Doxycycline 100 mg one hour before the procedure
  3. Clindamycin 600 mg one hour before the procedure
  4. Azithromycin 500 mg one hour before the procedure Correct answer.

Explanation

For patients with a penicillin allergy, a macrolide such as azithromycin is a recommended alternative for infective endocarditis prophylaxis. Clindamycin is no longer favoured because of the risk of Clostridioides difficile colitis.

Question 11Dental Surgery

A patient presents with a firm, non-tender swelling at the angle of the mandible that has been present for three months. Which investigation is most appropriate to characterise the lesion?

  1. Bitewing radiograph
  2. Fine needle aspiration cytology Correct answer.
  3. Salivary flow rate measurement
  4. Pulp sensibility testing

Explanation

A persistent firm swelling at the mandibular angle requires tissue diagnosis, and fine needle aspiration cytology provides a minimally invasive initial assessment. It helps distinguish reactive, cystic and neoplastic lesions before definitive surgery.

Question 12Dental Surgery

During a surgical extraction, a patient suddenly becomes pale, sweaty and reports feeling faint. Which immediate action is most appropriate?

  1. Administer a further local anaesthetic injection
  2. Sit the patient upright and give a hot drink
  3. Lay the patient supine and raise the legs Correct answer.
  4. Continue the procedure without interruption

Explanation

These features suggest a vasovagal syncope, and the immediate management is to lay the patient supine with legs elevated to improve cerebral perfusion. The procedure should be paused while the patient recovers.

Question 13Dental Surgery

Which factor most increases the risk of a dry socket after extraction of a lower molar?

  1. Female sex under the age of 30
  2. Use of a chlorhexidine mouthwash
  3. Smoking in the post-operative period Correct answer.
  4. A single dose of pre-operative antibiotic

Explanation

Smoking impairs healing and is a well-established risk factor for alveolar osteitis after extraction. Patients should be advised to avoid smoking in the post-operative period to reduce this risk.

Question 14Dental Surgery

Which local anaesthetic property makes articaine particularly useful for buccal infiltration in the mandible?

  1. Short duration of action
  2. Absence of vasoconstrictor
  3. High lipid solubility and protein binding Correct answer.
  4. Low pKa relative to tissue pH

Explanation

Articaine has high lipid solubility and protein binding, which allows good diffusion through bone and prolonged duration. This makes buccal infiltration effective for mandibular teeth in many cases.

Question 15Dental Surgery

A patient with a mandibular first molar that is grossly carious and unrestorable requests extraction. Which pre-operative consideration is most important?

  1. Assessing the patient's dietary sugar intake
  2. Assessing the opposing tooth for over-eruption
  3. Confirming the tooth is restorable
  4. Checking the patient's bleeding history and anticoagulant use Correct answer.

Explanation

Before extraction, the patient's bleeding history and use of anticoagulants must be reviewed to plan safe haemostasis. This is a key pre-operative safety consideration for any surgical procedure.

Question 16Dental Surgery

Which statement best describes the mechanism of action of local anaesthetics on nerve conduction?

  1. They block voltage-gated sodium channels in the nerve membrane Correct answer.
  2. They increase the resting membrane potential
  3. They enhance potassium efflux from the axon
  4. They stimulate calcium influx at the synaptic terminal

Explanation

Local anaesthetics block voltage-gated sodium channels, preventing depolarisation and propagation of the action potential. This produces reversible loss of sensation in the area supplied by the nerve.

Question 17Dental Surgery

A patient is taking warfarin and requires a simple extraction. Which pre-operative measure is most appropriate?

  1. Double the warfarin dose on the day of extraction
  2. Stop warfarin five days before the extraction without medical advice
  3. Check the INR and ensure it is within the therapeutic range before proceeding Correct answer.
  4. Give fresh frozen plasma before the extraction

Explanation

For patients on warfarin, the INR should be checked and confirmed to be within the therapeutic range before a simple extraction. Local haemostatic measures are then used to control bleeding.

Question 18Dental Surgery

Which of the following is the most appropriate initial management for a patient with a displaced mandibular third molar root into the submandibular space during extraction?

  1. Prescribe antibiotics and discharge
  2. Attempt immediate retrieval through the socket
  3. Arrange urgent referral for imaging and surgical retrieval Correct answer.
  4. Reassure the patient and review in six months

Explanation

A displaced root into the submandibular space requires imaging to localise it and surgical retrieval, usually by an oral and maxillofacial surgeon. Blind attempts through the socket may cause further damage.

Question 19Dental Surgery

Which anatomical landmark is used to locate the greater palatine foramen for a greater palatine nerve block?

  1. The hamular notch Correct answer.
  2. The mental foramen
  3. The incisive papilla
  4. The retromolar pad

Explanation

The greater palatine foramen lies anterior to the hamular notch, and this landmark guides placement of the needle for a greater palatine nerve block. The injection anaesthetises the posterior hard palate.

Question 20Dental Surgery

A patient reports persistent bleeding from an extraction socket two hours after surgery. Which initial measure is most appropriate?

  1. Rinse the socket vigorously with water
  2. Apply firm pressure by biting on a gauze pack for 20 minutes Correct answer.
  3. Apply a hot compress to the face
  4. Lie the patient flat and give aspirin

Explanation

The initial management of post-extraction bleeding is firm pressure over the socket with a gauze pack for about 20 minutes. This promotes clot formation and is usually sufficient for minor bleeding.

Question 21Dental Surgery

Which factor is most important in determining the difficulty of a surgical extraction of a lower third molar?

  1. The patient's preferred hand for brushing
  2. The colour of the tooth
  3. The angulation of the tooth and its relationship to the inferior alveolar canal Correct answer.
  4. The number of previous restorations in the adjacent tooth

Explanation

The angulation of the tooth and its proximity to the inferior alveolar canal are key determinants of surgical difficulty and risk. These factors influence the surgical approach and consent for nerve injury.

Question 22Dental Surgery

A patient with a history of osteoradionecrosis risk requires extraction of a mandibular molar after radiotherapy to the head and neck. Which precaution is most important?

  1. Use a high-speed drill to remove bone around the tooth
  2. Perform the extraction without any modification
  3. Delay all treatment indefinitely
  4. Avoid extraction and consider restorative options where possible Correct answer.

Explanation

In patients with previous head and neck radiotherapy, extraction carries a risk of osteoradionecrosis, so restorative alternatives should be considered first. If extraction is unavoidable, an atraumatic technique with careful planning is required.

Question 23Dental Surgery

Which of the following best explains why a mandibular block may fail to anaesthetise the lower incisors?

  1. The long buccal nerve supplies the incisors
  2. The lingual nerve supplies the incisor pulps
  3. The mental nerve block is required for incisor anaesthesia
  4. Accessory innervation from the contralateral inferior alveolar nerve Correct answer.

Explanation

The lower incisors may receive accessory innervation from the contralateral inferior alveolar nerve, which can cause failure of a unilateral block. This explains why some patients require additional infiltration or a bilateral block.

Question 24Dental Surgery

A patient with a mandibular fracture is being assessed. Which clinical finding is most suggestive of a fracture of the mandibular body?

  1. Step deformity in the occlusion and mobility of segments Correct answer.
  2. Increased salivary flow
  3. Generalised gingival bleeding
  4. Bilateral tenderness of the temporomandibular joints

Explanation

A step deformity in the occlusion with mobility of segments is a classic sign of a mandibular body fracture. It reflects discontinuity of the bone and disruption of the dental arch.

Question 25Dental Surgery

Which of the following is the most appropriate definitive management for a patient with a large odontogenic keratocyst of the mandible?

  1. Simple aspiration without further treatment
  2. Enucleation with adjunctive measures such as peripheral ostectomy or Carnoy's solution Correct answer.
  3. Incision and drainage
  4. Observation alone with annual radiographs

Explanation

Odontogenic keratocysts have a high recurrence rate, so definitive management usually involves enucleation with adjunctive measures such as peripheral ostectomy or Carnoy's solution. Simple aspiration or observation alone is inadequate.

Question 26Dental Surgery

Which instrument is designed specifically for elevating a tooth from its socket during a forceps extraction?

  1. Excavator
  2. Sickle scaler
  3. Coupland elevator Correct answer.
  4. Dental hatchet

Explanation

A Coupland elevator is a broad-bladed instrument used to apply controlled force between the tooth root and alveolar bone, loosening the tooth before forceps application. The other instruments listed are designed for restorative or periodontal tasks rather than luxation of a tooth.

Question 27Dental Surgery

Which suture needle shape is most appropriate for suturing the buccal mucosa in the posterior mandible where access is restricted?

  1. Straight cutting needle
  2. Three-eighths circle reverse cutting needle Correct answer.
  3. Five-eighths circle taper needle
  4. Half-circle cutting needle

Explanation

A three-eighths circle reverse cutting needle is well suited to intraoral mucosal closure because the small arc allows rotation within a confined space and the reverse cutting edge reduces tissue tear-out. Larger arcs and straight needles require more room to manoeuvre than is available posteriorly.

Question 28Dental Surgery

Which clinical feature most strongly suggests that a swelling of dental origin is a cellulitis rather than an abscess?

  1. A well-localised swelling with a discharging sinus tract
  2. A firm, diffuse, tender swelling with ill-defined margins Correct answer.
  3. A soft, cystic swelling that transilluminates
  4. A fluctuant centre with a pointing sinus

Explanation

Cellulitis presents as a diffuse, firm, tender swelling with poorly defined margins because inflammation spreads through tissue planes rather than being contained. A localised fluctuant collection with pointing or discharge indicates a drained or contained abscess instead.

Question 29Dental Surgery

Which anatomical structure must be identified and protected when raising a buccal flap in the anterior mandible to avoid injury during surgery?

  1. The lingual nerve in the floor of the mouth
  2. The long buccal nerve at the retromolar pad
  3. The mental nerve at the mental foramen Correct answer.
  4. The greater palatine artery

Explanation

The mental nerve exits at the mental foramen in the premolar region of the mandible, and a buccal flap extending into this area risks stretching or transecting it. The other structures listed are located in the palate, floor of mouth, or retromolar region and are not at risk from an anterior buccal flap.

Question 30Dental Surgery

A patient develops a dry socket three days after extraction of a lower first molar. Which management is most appropriate?

  1. Prescription of a two-week course of oral antibiotics alone
  2. Immediate replacement of the socket with a bone graft
  3. Re-suturing of the socket under local anaesthetic
  4. Irrigation of the socket and placement of a medicated dressing Correct answer.

Explanation

The aim in alveolar osteitis is to relieve pain and promote healing by gently irrigating the socket to remove debris and placing a medicated dressing such as a zinc oxide-eugenol or chlorhexidine-soaked pack. Antibiotics are not indicated for a localised dry socket and grafting or resuturing is not the initial step.

Question 31Dental Surgery

Which radiographic feature is most characteristic of a dentigerous cyst associated with an impacted mandibular third molar?

  1. A generalised widening of the periodontal ligament space
  2. A diffuse ground-glass opacity of the mandible
  3. A radiolucency with irregular, moth-eaten margins at the root apex
  4. A well-defined radiolucency attached at the cementoenamel junction of the crown Correct answer.

Explanation

A dentigerous cyst encloses the crown of an unerupted tooth and attaches at the cementoenamel junction, producing a well-defined radiolucency around the crown. The other patterns describe periapical pathology, malignancy, or fibro-osseous lesions rather than a dentigerous cyst.

Question 32Dental Surgery

Which local anaesthetic agent has the longest duration of action when used for a mandibular block?

  1. Bupivacaine 0.5% with adrenaline 1:200,000 Correct answer.
  2. Mepivacaine 3% plain
  3. Lidocaine 2% with adrenaline 1:80,000
  4. Prilocaine 4% plain

Explanation

Bupivacaine is highly protein-bound and has a long duration of action, providing pulpal anaesthesia of several hours and soft tissue anaesthesia lasting considerably longer. Lidocaine, mepivacaine, and prilocaine provide shorter pulpal anaesthesia.

Question 33Dental Surgery

Which clinical sign is most consistent with a diagnosis of Ludwig's angina?

  1. A chronic discharging sinus at the angle of the mandible
  2. A localised palatal abscess with a sinus tract
  3. Unilateral fluctuant swelling confined to the buccal space
  4. Bilateral submandibular and sublingual swelling with elevation of the tongue Correct answer.

Explanation

Ludwig's angina is a rapidly spreading bilateral cellulitis of the submandibular and sublingual spaces that raises the tongue and threatens the airway. Unilateral fluctuant or chronic discharging lesions do not fit this picture.

Question 34Dental Surgery

Which factor is the strongest predictor of a difficult intubation that must be assessed before general anaesthesia for oral surgery?

  1. A thyromental distance greater than 6.5 cm
  2. A Mallampati class IV airway with limited mouth opening Correct answer.
  3. A body mass index within the normal range
  4. A Mallampati class I airway

Explanation

A high Mallampati score combined with reduced mouth opening indicates poor visibility of the larynx and restricted access, both strong predictors of difficult intubation. The other findings are associated with easier airway management.

Question 35Dental Surgery

Which is the most appropriate initial management for a patient with a displaced root fragment into the maxillary sinus during extraction?

  1. Reassure the patient and review in six months
  2. Attempt blind retrieval with forceps through the socket
  3. Arrange urgent imaging and antibiotic cover, then refer for specialist retrieval Correct answer.
  4. Refer for immediate surgical removal via a Caldwell-Luc approach

Explanation

A root displaced into the maxillary sinus requires imaging to confirm its position and prophylactic antibiotics to reduce the risk of sinusitis, followed by specialist retrieval. Blind probing risks pushing the fragment deeper or causing further injury.

Question 36Dental Surgery

Which clinical finding best differentiates a periapical abscess from a periodontal abscess on examination?

  1. The swelling is fluctuant and pointing towards the buccal sulcus
  2. The tooth is vital and there is a deep periodontal pocket with a narrow entrance
  3. There is generalised gingival inflammation affecting all quadrants
  4. The tooth is tender to percussion and non-vital on pulp testing Correct answer.

Explanation

A periapical abscess arises from a necrotic pulp, so the tooth is non-vital and tender to percussion. A periodontal abscess typically occurs in a vital tooth with a deep pocket and often a narrow pocket entrance.

Question 37Dental Surgery

Which structure is at greatest risk of injury during surgical removal of a deeply impacted mandibular third molar with roots close to the inferior alveolar canal?

  1. The chorda tympani
  2. The inferior alveolar nerve Correct answer.
  3. The mylohyoid nerve
  4. The auriculotemporal nerve

Explanation

The inferior alveolar nerve runs within the mandibular canal and lies in close proximity to the roots of the lower third molar, making it the structure most vulnerable during surgical removal. The other nerves listed are not located in the surgical field at the third molar site.

Question 38Dental Surgery

Which of the following is the most appropriate first-line treatment for a localised acute dentoalveolar abscess with systemic involvement in a fit adult?

  1. Incision and drainage with extraction or root canal treatment and appropriate antibiotics Correct answer.
  2. Long-term antibiotic therapy without drainage
  3. Analgesia alone with review in one week
  4. Application of a cold compress and observation

Explanation

The principles of managing an acute dentoalveolar abscess with systemic involvement are to establish drainage, remove the source of infection by extraction or root canal treatment, and prescribe antibiotics when there is systemic spread. Drainage is essential because antibiotics alone cannot penetrate a collection.

Question 39Dental Surgery

Which clinical test is used to assess the viability of the pulp in a tooth suspected of having a periapical infection?

  1. Percussion testing
  2. Electric pulp testing Correct answer.
  3. Transillumination
  4. Mobility testing

Explanation

Electric pulp testing assesses the responsiveness of the pulp to an electrical stimulus and helps determine whether the pulp is vital or necrotic. Percussion and mobility tests assess the periodontal tissues, while transillumination detects cracks and caries.

Question 40Dental Surgery

Which nerve block provides anaesthesia of the buccal soft tissues and periosteum adjacent to the mandibular molars?

  1. Long buccal nerve block Correct answer.
  2. Inferior alveolar nerve block
  3. Mental nerve block
  4. Greater palatine nerve block

Explanation

The long buccal nerve supplies the buccal gingiva and periosteum of the mandibular molar region and is blocked by infiltration near the retromolar area. The inferior alveolar block anaesthetises the teeth and anterior soft tissues, while the mental and greater palatine blocks supply different regions.

Question 41Dental Surgery

Which precaution is most important before extracting a tooth in a patient taking long-term bisphosphonates for osteoporosis?

  1. Assess the cumulative risk and consider conservative treatment or specialist referral before extraction Correct answer.
  2. Prescribe antibiotics for one week after extraction
  3. Perform the extraction with a vasoconstrictor-free local anaesthetic
  4. Stop the bisphosphonate six months before surgery

Explanation

Patients on long-term bisphosphonates are at risk of medication-related osteonecrosis of the jaw, so the cumulative exposure and risk should be assessed and conservative or specialist management considered before extraction. Stopping the drug does not reliably reverse the risk and antibiotics alone do not prevent osteonecrosis.

Question 42Dental Surgery

Which clinical feature is most suggestive of a malignant rather than a benign salivary gland swelling?

  1. A rapidly growing, fixed, painful mass with facial nerve palsy Correct answer.
  2. A bilateral diffuse enlargement associated with systemic disease
  3. A soft, mobile, painless parotid swelling of many years' duration
  4. A fluctuant swelling that resolves with sialagogue therapy

Explanation

Rapid growth, fixation to surrounding tissue, pain, and facial nerve palsy are red flags for malignancy in a salivary gland swelling. Long-standing, mobile, painless swellings and bilateral diffuse enlargement are more typical of benign or systemic conditions.

Question 43Dental Surgery

Which is the most appropriate method of achieving haemostasis after a simple extraction in a patient with a normal clotting profile?

  1. Place a gauze pack and apply firm pressure for several minutes Correct answer.
  2. Apply a cold compress to the cheek
  3. Suture the socket tightly without a pack
  4. Irrigate the socket with hydrogen peroxide

Explanation

Firm pressure with a gauze pack over the socket for several minutes allows a stable clot to form and is the first-line method of achieving haemostasis. Tight suturing without a pack, chemical irrigation, or a cold compress does not directly promote clot formation in the socket.

Question 44Dental Surgery

Which anatomical space is most commonly involved when an infection from a mandibular second molar spreads posteriorly?

  1. The pterygomandibular space
  2. The sublingual space
  3. The submandibular space Correct answer.
  4. The buccal space

Explanation

Infection from mandibular molars whose roots lie below the mylohyoid attachment typically spreads into the submandibular space. Sublingual spread occurs with anterior teeth above the mylohyoid line, while buccal and pterygomandibular spaces are involved in other patterns.

Question 45Dental Surgery

Which of the following is the most reliable clinical indicator of successful inferior alveolar nerve block?

  1. Numbness of the lower lip and chin Correct answer.
  2. Numbness of the buccal gingiva
  3. Loss of sensation on the palate
  4. Numbness of the tongue only

Explanation

Numbness of the lower lip and chin indicates anaesthesia of the mental nerve distribution, which confirms that the inferior alveolar nerve has been successfully blocked. Buccal and palatal numbness are supplied by other nerves and do not confirm the block.

Question 46Dental Surgery

Which factor most increases the likelihood of a mandibular third molar being classified as a difficult surgical extraction?

  1. A vertical impaction with a wide follicular space
  2. A fully erupted tooth with a single root
  3. A tooth with a short, conical root
  4. A mesioangular impaction with roots overlapping the inferior alveolar canal Correct answer.

Explanation

A mesioangular impaction with roots overlapping the inferior alveolar canal increases surgical difficulty because of the need for bone removal and the risk of nerve injury. Fully erupted teeth, vertical impactions, and short conical roots are generally easier to remove.

Question 47Dental Surgery

Which of the following is the most appropriate management for a patient with a fractured mandible at the angle who is otherwise stable?

  1. Reassure and discharge with soft diet
  2. Perform immediate extraction of all teeth in the fracture line
  3. Refer for maxillofacial assessment and fixation Correct answer.
  4. Prescribe antibiotics and review in one month

Explanation

A fractured mandible requires maxillofacial assessment and appropriate fixation to restore occlusion and allow healing. Discharging the patient, delaying review, or extracting teeth in the fracture line without specialist assessment is inappropriate.

Question 48Dental Surgery

Which is the most appropriate antibiotic prophylaxis regimen for a patient with a prosthetic heart valve undergoing a dental extraction, according to current guidance?

  1. No prophylaxis is required for any cardiac condition
  2. A single dose of metronidazole 400 mg after the procedure
  3. A five-day course of amoxicillin starting on the day of surgery
  4. A single dose of amoxicillin 2 g orally one hour before the procedure Correct answer.

Explanation

Current guidance recommends a single oral dose of amoxicillin 2 g taken one hour before the procedure for patients at high risk of infective endocarditis, such as those with a prosthetic heart valve. Prolonged courses or post-procedure dosing are not recommended for routine prophylaxis.

Question 49Dental Surgery

Which clinical sign most strongly suggests a diagnosis of oral squamous cell carcinoma in a persistent ulcer?

  1. A painless ulcer with rolled, everted margins and induration Correct answer.
  2. A shallow ulcer associated with aphthous stomatitis
  3. A painful ulcer that heals within two weeks
  4. A white patch that resolves after removing local irritants

Explanation

A persistent painless ulcer with rolled, everted margins and a firm indurated base is a classic presentation of oral squamous cell carcinoma and warrants urgent referral. Healing ulcers, aphthous ulcers, and reversible white patches are more typical of benign conditions.

Question 50Dental Surgery

Which of the following is the most appropriate initial step when a patient reports a broken instrument tip remaining in the socket after extraction?

  1. Suture the socket and review in three months
  2. Attempt to retrieve it blindly with a probe
  3. Ignore it as it will resorb
  4. Take a radiograph to locate the fragment and refer if it cannot be safely retrieved Correct answer.

Explanation

A retained instrument fragment should be localised radiographically and retrieved if this can be done safely, with referral to a specialist if not. Blind probing risks pushing the fragment deeper, and leaving a metal fragment in situ risks infection and complications.