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Arab Board OMFS Part 1 study materials
Arab Board OMFS Part 1 study resources

Arab Board OMFS Part 1 practice questions

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Question 1Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which nerve provides sensory innervation to the buccal gingiva of the mandibular posterior teeth?

  1. Inferior alveolar nerve
  2. Mylohyoid nerve
  3. Long buccal nerve Correct answer.
  4. Lingual nerve

Explanation

The long buccal nerve, a branch of the anterior division of the mandibular nerve, supplies the buccal gingiva and mucosa of the mandibular molars. The inferior alveolar nerve supplies the teeth and chin, while the lingual nerve is sensory to the lingual gingiva and tongue.

Question 2Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

The temporomandibular joint disc is primarily composed of which tissue?

  1. Fibrocartilage Correct answer.
  2. Elastic cartilage
  3. Dense regular collagenous tissue without cells
  4. Hyaline cartilage

Explanation

The articular disc of the TMJ is fibrocartilaginous, unlike most synovial joints which have hyaline cartilage. Fibrocartilage resists compression and shear, suited to the loading pattern of the joint.

Question 3Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which muscle is the primary depressor of the mandible during opening?

  1. Medial pterygoid
  2. Lateral pterygoid Correct answer.
  3. Temporalis
  4. Masseter

Explanation

The lateral pterygoid, particularly its inferior head, protrudes and depresses the mandible and is the main opener along with suprahyoid muscles. The masseter, temporalis, and medial pterygoid are elevators.

Question 4Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which cranial nerve carries taste from the anterior two-thirds of the tongue?

  1. Glossopharyngeal nerve
  2. Trigeminal nerve
  3. Hypoglossal nerve
  4. Facial nerve via chorda tympani Correct answer.

Explanation

Taste from the anterior two-thirds of the tongue is carried by the chorda tympani branch of the facial nerve. General sensation from the same region is carried by the lingual branch of the trigeminal nerve.

Question 5Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which cell type is primarily responsible for bone resorption during orthodontic tooth movement?

  1. Osteoclast Correct answer.
  2. Osteocyte
  3. Fibroblast
  4. Osteoblast

Explanation

Osteoclasts are multinucleated cells derived from the monocyte lineage that resorb bone on the pressure side of orthodontic force. Osteoblasts form bone on the tension side.

Question 6Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which immunoglobulin is the predominant antibody in saliva and other mucosal secretions?

  1. IgG
  2. IgM
  3. IgE
  4. IgA Correct answer.

Explanation

Secretory IgA is the dominant immunoglobulin in mucosal secretions including saliva, where it neutralizes pathogens. IgG predominates in serum, IgM is a primary response antibody, and IgE mediates allergy.

Question 7Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which vitamin deficiency is classically associated with impaired collagen cross-linking and poor wound healing?

  1. Vitamin C Correct answer.
  2. Vitamin A
  3. Vitamin D
  4. Vitamin K

Explanation

Vitamin C is a cofactor for prolyl and lysyl hydroxylase, which are required for collagen cross-linking and stable wound healing. Deficiency causes scurvy with defective connective tissue.

Question 8Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which structure lies immediately medial to the mandibular ramus and is at risk during third molar surgery?

  1. Buccal artery
  2. Facial artery
  3. Lingual nerve Correct answer.
  4. Masseteric artery

Explanation

The lingual nerve runs medial to the mandible in the floor of the mouth and is at risk during lingual flap retraction in third molar surgery. The facial artery crosses lateral to the mandible.

Question 9Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A patient has a lesion of the marginal mandibular branch of the facial nerve. Which finding is expected?

  1. Loss of taste on the anterior tongue
  2. Loss of forehead wrinkling
  3. Inability to close the eye
  4. Drooping of the lower lip corner Correct answer.

Explanation

The marginal mandibular branch supplies the depressors of the lower lip, so injury causes asymmetry and drooping of the lower lip corner on the affected side. Eye closure and forehead wrinkling are upper facial nerve functions.

Question 10Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best explains why local anesthetics with epinephrine are avoided in patients on nonselective beta-blockers?

  1. Epinephrine causes direct myocardial depression
  2. Beta-blockers inactivate the local anesthetic
  3. Epinephrine causes methemoglobinemia
  4. Unopposed alpha stimulation may precipitate hypertension Correct answer.

Explanation

Nonselective beta blockade leaves alpha-mediated vasoconstriction unopposed, so exogenous epinephrine can raise blood pressure and cause reflex bradycardia. Prilocaine, not epinephrine, is linked to methemoglobinemia.

Question 11Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A 60-year-old smoker presents with a painless, non-healing ulcer on the lateral border of the tongue. Which histologic finding most strongly supports squamous cell carcinoma?

  1. Hyperkeratosis without atypia
  2. Lymphocytic infiltrate in the lamina propria
  3. Increased melanin in basal keratinocytes
  4. Keratin pearls with invasion through the basement membrane Correct answer.

Explanation

Invasion through the basement membrane with keratin pearl formation indicates well-differentiated squamous cell carcinoma. Hyperkeratosis or inflammation alone are nonspecific reactive changes.

Question 12Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which statement best describes the mechanism of action of amide local anesthetics?

  1. They block calcium channels at the presynaptic terminal
  2. They block voltage-gated sodium channels from the internal surface Correct answer.
  3. They enhance GABA receptor activity
  4. They activate potassium channels to hyperpolarize the membrane

Explanation

Amide anesthetics are weak bases that cross the membrane in uncharged form and block voltage-gated sodium channels from within, preventing depolarization. They do not act primarily on potassium, calcium, or GABA receptors.

Question 13Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which factor most increases the risk of osteoradionecrosis after tooth extraction?

  1. History of orthodontic treatment
  2. Extraction of a maxillary incisor
  3. Use of local anesthesia
  4. A radiation dose above 60 Gy to the mandible Correct answer.

Explanation

Cumulative radiation doses above 60 Gy to the mandible markedly impair vascularity and healing, increasing osteoradionecrosis risk. Maxillary extractions carry lower risk, and local anesthesia or orthodontics are not major risk factors.

Question 14Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following is the most common site of metastasis to the cervical lymph nodes from oral squamous cell carcinoma of the tongue?

  1. Level VI nodes
  2. Submental nodes
  3. Level I and II nodes Correct answer.
  4. Retropharyngeal nodes

Explanation

Oral tongue SCC most commonly metastasizes first to level I and II nodes, particularly the submandibular and upper jugular nodes. Level VI and retropharyngeal nodes are less typical for anterior oral cavity lesions.

Question 15Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A patient with a mandibular fracture has anesthesia of the chin and lower lip. Which structure is most likely injured?

  1. Mylohyoid nerve
  2. Mental nerve at the mental foramen Correct answer.
  3. Long buccal nerve
  4. Chorda tympani

Explanation

The mental nerve exits at the mental foramen and supplies the chin and lower lip, so anesthesia there suggests injury near the foramen, often with a parasymphyseal fracture. The long buccal, mylohyoid, and chorda tympani nerves supply other territories.

Question 16Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best describes the role of osteoprotegerin (OPG) in bone metabolism?

  1. It promotes osteoclast differentiation
  2. It stimulates osteoblast apoptosis
  3. It increases calcium resorption from bone
  4. It acts as a decoy receptor for RANKL Correct answer.

Explanation

Osteoprotegerin binds RANKL and prevents it from activating RANK on osteoclast precursors, thereby inhibiting osteoclastogenesis. A high OPG-to-RANKL ratio favors reduced bone resorption.

Question 17Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A patient develops fever, trismus, and a swollen floor of the mouth with elevation of the tongue after a lower molar infection. Which space is most immediately life-threatening if involved?

  1. Buccal space
  2. Sublingual space
  3. Canine space
  4. Ludwig angina involving submandibular and sublingual spaces bilaterally Correct answer.

Explanation

Bilateral submandibular and sublingual space involvement constitutes Ludwig angina, which can obstruct the airway and is a surgical emergency. Buccal or canine space infections are less immediately airway-threatening.

Question 18Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best explains the anticoagulant effect of warfarin relevant to minor oral surgery?

  1. Blockade of platelet glycoprotein IIb/IIIa
  2. Inhibition of vitamin K epoxide reductase reducing factors II, VII, IX, X Correct answer.
  3. Activation of antithrombin III
  4. Direct inhibition of thrombin

Explanation

Warfarin inhibits vitamin K epoxide reductase, reducing synthesis of functional factors II, VII, IX, and X. The INR guides perioperative management for minor oral surgery.

Question 19Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following is the primary mechanism by which smoking impairs periodontal healing?

  1. Increased collagen synthesis
  2. Enhanced fibroblast proliferation
  3. Increased salivary flow
  4. Vasoconstriction and impaired neutrophil function Correct answer.

Explanation

Nicotine causes vasoconstriction and smoking impairs neutrophil chemotaxis and collagen synthesis, reducing tissue perfusion and healing. It does not enhance fibroblast proliferation or collagen synthesis.

Question 20Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following statements about the blood supply of the mandible is most accurate?

  1. The inferior alveolar artery is the sole supply to the body of the mandible
  2. The mandible is supplied only by the facial artery
  3. The mandible receives both medullary and periosteal supply, with the periosteal supply becoming more important with age Correct answer.
  4. The mandible has no medullary blood supply

Explanation

The mandible has a dual medullary and periosteal supply; with age the medullary supply diminishes and the periosteal supply becomes more important. This matters in surgery where periosteal stripping can compromise healing.

Question 21Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best explains why the submandibular space is a common site for the spread of mandibular molar infections?

  1. The mylohyoid muscle attaches to the mylohyoid line, and apices below it drain into the submandibular space Correct answer.
  2. The lingual nerve provides a direct conduit
  3. The submandibular gland secretes chemotactic factors
  4. The buccinator muscle directs pus into the submandibular space

Explanation

The mylohyoid line divides the sublingual from the submandibular space; molar root apices below the line drain into the submandibular space. This anatomical relationship explains the pattern of spread.

Question 22Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best describes the significance of the pterygomandibular space in inferior alveolar nerve block?

  1. It contains the inferior alveolar nerve before it enters the mandibular foramen Correct answer.
  2. It communicates only with the buccal space
  3. It contains the facial artery
  4. It is superficial to the masseter

Explanation

The pterygomandibular space contains the inferior alveolar and lingual nerves and vessels as they descend toward the mandibular foramen, making it the target for the block. The facial artery is not in this space.

Question 23Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A biopsy of a gingival mass shows a proliferation of spindle cells with abundant collagen and a storiform pattern. Which diagnosis is most consistent?

  1. Fibromatosis Correct answer.
  2. Lymphoma
  3. Squamous cell carcinoma
  4. Pleomorphic adenoma

Explanation

A storiform spindle cell proliferation with abundant collagen suggests fibromatosis, a locally aggressive fibrous lesion. SCC would show epithelial atypia, pleomorphic adenoma shows glandular and myxochondroid elements, and lymphoma is lymphoid.

Question 24Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best explains the increased bleeding risk in a patient with chronic liver disease undergoing extraction?

  1. Reduced synthesis of clotting factors and possible thrombocytopenia Correct answer.
  2. Enhanced platelet aggregation
  3. Increased vitamin K absorption
  4. Overproduction of von Willebrand factor

Explanation

Chronic liver disease reduces synthesis of vitamin K-dependent and other clotting factors and can cause hypersplenic thrombocytopenia, increasing bleeding risk. It does not enhance platelet aggregation or vitamin K absorption.

Question 25Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best explains why the posterior superior alveolar nerve block can cause a hematoma?

  1. The nerve lies within the masseter
  2. The nerve lies within the parotid gland
  3. The nerve lies near the pterygoid venous plexus Correct answer.
  4. The nerve lies near the facial artery

Explanation

The posterior superior alveolar nerve lies in the infratemporal fossa near the pterygoid venous plexus, so needle misdirection can cause a hematoma. The facial artery, masseter, and parotid gland are not in this relationship.

Question 26Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which cranial nerve provides motor innervation to the muscles of mastication?

  1. Trigeminal nerve (CN V) Correct answer.
  2. Hypoglossal nerve (CN XII)
  3. Glossopharyngeal nerve (CN IX)
  4. Facial nerve (CN VII)

Explanation

The trigeminal nerve's mandibular division (V3) supplies motor fibers to the four muscles of mastication: masseter, temporalis, and medial and lateral pterygoids. The facial nerve innervates muscles of facial expression, while the glossopharyngeal and hypoglossal nerves serve other functions.

Question 27Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which enzyme is primarily responsible for the activation of trypsinogen in the small intestine?

  1. Lipase
  2. Pepsin
  3. Enterokinase Correct answer.
  4. Amylase

Explanation

Enterokinase (enteropeptidase), an enzyme secreted by the duodenal mucosa, cleaves trypsinogen to form active trypsin. Trypsin then activates other pancreatic zymogens. Pepsin is a gastric protease, while amylase and lipase are digestive enzymes that do not activate trypsinogen.

Question 28Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which type of collagen is most abundant in the periodontal ligament?

  1. Type I Correct answer.
  2. Type III
  3. Type IV
  4. Type II

Explanation

The periodontal ligament is composed predominantly of type I collagen, which provides tensile strength. Type II is found in cartilage, type III in reticular fibers and early wound healing, and type IV in basement membranes.

Question 29Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which immunoglobulin class is the first to be produced in a primary immune response?

  1. IgG
  2. IgE
  3. IgA
  4. IgM Correct answer.

Explanation

IgM is the first antibody isotype expressed during a primary immune response, followed by IgG. IgA is important in mucosal immunity, IgG predominates in secondary responses, and IgE mediates allergic reactions.

Question 30Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which vitamin is essential for the synthesis of prothrombin and several other clotting factors?

  1. Vitamin D
  2. Vitamin C
  3. Vitamin K Correct answer.
  4. Vitamin A

Explanation

Vitamin K is a cofactor for the gamma-carboxylation of glutamate residues in clotting factors II, VII, IX, and X, as well as proteins C and S. Vitamin C is needed for collagen synthesis, vitamin D for calcium homeostasis, and vitamin A for vision and epithelial integrity.

Question 31Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which nerve is most likely to be injured during a difficult extraction of a mandibular third molar, leading to loss of sensation on the ipsilateral lower lip and chin?

  1. Mylohyoid nerve
  2. Inferior alveolar nerve Correct answer.
  3. Buccal nerve
  4. Lingual nerve

Explanation

The inferior alveolar nerve provides sensory innervation to the lower lip and chin via its mental branch. It runs in the mandibular canal and is at risk during third molar surgery. The lingual nerve supplies the tongue, the mylohyoid nerve the floor of the mouth, and the buccal nerve the cheek mucosa.

Question 32Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following is the primary mineral component of dental enamel?

  1. Brushite
  2. Amorphous calcium phosphate
  3. Hydroxyapatite Correct answer.
  4. Octacalcium phosphate

Explanation

Enamel is composed primarily of hydroxyapatite crystals, which are highly organized and make up about 96% of its weight. The other calcium phosphates listed are precursors or less stable forms not predominant in mature enamel.

Question 33Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best describes the role of the sodium-potassium pump in maintaining the resting membrane potential of a neuron?

  1. It pumps calcium ions out of the cell to maintain a negative interior.
  2. It pumps three sodium ions in and two potassium ions out, making the interior positive.
  3. It pumps equal numbers of sodium and potassium ions, resulting in no net charge difference.
  4. It pumps three sodium ions out and two potassium ions in, contributing to a negative interior. Correct answer.

Explanation

The Na+/K+-ATPase moves three Na+ out and two K+ in per ATP hydrolyzed, creating a net loss of positive charge intracellularly and contributing to the negative resting membrane potential. This electrogenic action is in addition to the concentration gradients it maintains.

Question 34Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A patient with a history of rheumatic fever is scheduled for a dental extraction. Which of the following is the most appropriate prophylaxis to prevent infective endocarditis?

  1. No prophylaxis is indicated for this patient
  2. Amoxicillin 2 g orally 30–60 minutes before the procedure Correct answer.
  3. Clindamycin 600 mg orally 30–60 minutes before the procedure
  4. Azithromycin 500 mg orally the day before the procedure

Explanation

Current guidelines recommend a single dose of amoxicillin 2 g orally 30–60 minutes before the procedure for patients with the highest risk of infective endocarditis, including those with prosthetic valves or a history of endocarditis. Rheumatic fever alone without valve damage is not an indication. Clindamycin is no longer recommended due to adverse effects, and azithromycin timing is incorrect.

Question 35Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best explains why a patient with a deficiency of vitamin B12 may present with glossitis and oral ulcerations?

  1. Vitamin B12 is essential for DNA synthesis, and rapidly dividing epithelial cells are affected. Correct answer.
  2. Vitamin B12 is a cofactor for keratin production in the tongue.
  3. Vitamin B12 is required for collagen cross-linking in the oral mucosa.
  4. Vitamin B12 deficiency causes increased iron absorption, leading to mucosal damage.

Explanation

Vitamin B12 is necessary for DNA synthesis, particularly in rapidly dividing cells such as those of the oral mucosa and bone marrow. Deficiency leads to megaloblastic changes and clinical manifestations like glossitis and ulcerations. The other options misrepresent the metabolic role of B12.

Question 36Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A 45-year-old woman presents with a painless swelling in the submandibular region that increases in size during meals. Which of the following is the most likely diagnosis?

  1. Submandibular space infection
  2. Lymphoma
  3. Pleomorphic adenoma
  4. Submandibular sialolithiasis Correct answer.

Explanation

A swelling that enlarges during meals is classic for sialolithiasis, as saliva flow is obstructed by a stone. Pleomorphic adenoma typically presents as a slow-growing, painless mass not related to meals. Infection would be painful, and lymphoma would not fluctuate with eating.

Question 37Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best describes the mechanism of action of nonsteroidal anti-inflammatory drugs (NSAIDs) relevant to oral surgery?

  1. Blockade of sodium channels
  2. Irreversible inhibition of cyclooxygenase
  3. Activation of opioid receptors
  4. Reversible inhibition of cyclooxygenase Correct answer.

Explanation

NSAIDs reversibly inhibit cyclooxygenase (COX), reducing prostaglandin synthesis and thereby decreasing inflammation and pain. Aspirin is the only NSAID that irreversibly inhibits COX. Opioid receptors and sodium channels are targets of other analgesic classes.

Question 38Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A patient with a history of type 2 diabetes mellitus undergoes a tooth extraction. Which of the following is the most important consideration for optimal healing?

  1. Prescribing antibiotics routinely
  2. Delaying surgery until HbA1c is below 6%
  3. Avoiding local anesthesia with epinephrine
  4. Ensuring good glycemic control before and after surgery Correct answer.

Explanation

Good glycemic control is critical for wound healing and reduces the risk of infection and delayed healing in diabetic patients. Routine antibiotics are not indicated unless there is an active infection. Epinephrine is generally safe in controlled diabetes, and an HbA1c target of 6% may be too stringent for many patients.

Question 39Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best explains the increased risk of bleeding in a patient with chronic liver disease undergoing oral surgery?

  1. Enhanced vitamin K absorption
  2. Increased platelet production
  3. Decreased synthesis of clotting factors Correct answer.
  4. Elevated von Willebrand factor levels

Explanation

The liver synthesizes most clotting factors, and chronic liver disease impairs their production, leading to coagulopathy. Platelet production is often decreased, not increased, and vitamin K absorption may be impaired. Von Willebrand factor levels may be elevated but do not compensate for factor deficiencies.

Question 40Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A patient with a deep neck infection originating from a mandibular molar develops difficulty breathing and a muffled voice. Which space is most likely involved?

  1. Submandibular space
  2. Parotid space
  3. Retropharyngeal space Correct answer.
  4. Ludwig's angina involving the sublingual and submandibular spaces

Explanation

Involvement of the retropharyngeal space can lead to airway compromise and a muffled voice due to swelling pressing on the pharynx. Ludwig's angina typically presents with bilateral submandibular swelling and elevation of the tongue, but the specific symptoms of breathing difficulty and voice change suggest retropharyngeal extension.

Question 41Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best describes the role of matrix metalloproteinases (MMPs) in periodontal disease?

  1. They stimulate osteoblast differentiation.
  2. They inhibit inflammatory cytokines.
  3. They degrade extracellular matrix components. Correct answer.
  4. They promote collagen synthesis.

Explanation

MMPs are enzymes that degrade collagen and other extracellular matrix components, contributing to tissue destruction in periodontal disease. They do not promote collagen synthesis or inhibit cytokines; rather, they are upregulated by inflammatory mediators.

Question 42Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following is the most likely cause of a prolonged bleeding time in a patient with normal platelet count and normal coagulation factors?

  1. von Willebrand disease Correct answer.
  2. Vitamin K deficiency
  3. Hemophilia A
  4. Liver cirrhosis

Explanation

von Willebrand disease is a platelet function disorder characterized by a prolonged bleeding time despite a normal platelet count. Hemophilia A and vitamin K deficiency affect coagulation factors and prolong the activated partial thromboplastin time or prothrombin time, not bleeding time.

Question 43Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best explains the analgesic effect of opioids?

  1. Activation of mu-opioid receptors in the central nervous system Correct answer.
  2. Blockade of sodium channels in peripheral nerves
  3. Stimulation of GABA release
  4. Inhibition of prostaglandin synthesis

Explanation

Opioids bind to mu-opioid receptors in the brain and spinal cord, inhibiting pain transmission. NSAIDs inhibit prostaglandin synthesis, local anesthetics block sodium channels, and GABA release is not the primary mechanism of opioids.

Question 44Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following statements about the blood supply of the maxilla is most accurate?

  1. The maxilla is supplied by branches of the maxillary artery, including the infraorbital and greater palatine arteries. Correct answer.
  2. The maxilla has a single end-arterial supply from the facial artery.
  3. The maxilla receives its blood supply primarily from the inferior alveolar artery.
  4. The maxilla is supplied mainly by the lingual artery.

Explanation

The maxilla receives a rich blood supply from branches of the maxillary artery, such as the infraorbital, greater palatine, and sphenopalatine arteries, which contribute to its good healing capacity. The inferior alveolar artery supplies the mandible, and the lingual artery supplies the tongue and floor of the mouth.

Question 45Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A patient with a history of angina takes sublingual nitroglycerin. During a stressful extraction, the patient develops chest pain. Which of the following is the most appropriate initial management?

  1. Administer the patient's nitroglycerin sublingually Correct answer.
  2. Start cardiopulmonary resuscitation
  3. Inject epinephrine intramuscularly
  4. Give aspirin 325 mg orally

Explanation

For angina pectoris, sublingual nitroglycerin is the first-line treatment to relieve ischemic pain by vasodilation. Aspirin is used for suspected myocardial infarction but is not the initial treatment for angina. CPR is reserved for cardiac arrest, and epinephrine is not indicated for angina.

Question 46Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best describes the primary mechanism by which local anesthetics block nerve conduction?

  1. They activate chloride channels.
  2. They block sodium channels. Correct answer.
  3. They inhibit calcium channels.
  4. They block potassium channels.

Explanation

Local anesthetics block voltage-gated sodium channels, preventing the influx of sodium ions necessary for depolarization and propagation of action potentials. They do not primarily affect potassium, chloride, or calcium channels.

Question 47Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A 30-year-old patient presents with a rapidly expanding hematoma after a posterior superior alveolar nerve block. Which artery is most likely injured?

  1. Buccal artery
  2. Facial artery
  3. Inferior alveolar artery
  4. Pterygoid venous plexus Correct answer.

Explanation

The posterior superior alveolar nerve block can inadvertently puncture the pterygoid venous plexus, leading to a hematoma. The inferior alveolar artery is at risk during inferior alveolar nerve block, and the facial artery is not in the vicinity of the PSA injection site.

Question 48Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following best explains why a patient with a history of penicillin allergy may be prescribed clindamycin for a dental infection?

  1. Clindamycin is bactericidal and penicillin is bacteriostatic.
  2. Clindamycin is effective against anaerobic bacteria and is an alternative for penicillin-allergic patients. Correct answer.
  3. Clindamycin has a broader spectrum than penicillin.
  4. Clindamycin is less likely to cause gastrointestinal side effects.

Explanation

Clindamycin is effective against many anaerobic bacteria involved in dental infections and is a suitable alternative for patients with penicillin allergy. It is not broader in spectrum, and it is associated with a risk of Clostridium difficile colitis. Penicillin is bactericidal, while clindamycin is typically bacteriostatic.

Question 49Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

Which of the following is the most likely consequence of a deficiency in vitamin C in a patient recovering from oral surgery?

  1. Increased risk of infection due to impaired immune function
  2. Delayed bone remodeling due to impaired osteoclast function
  3. Impaired collagen synthesis and delayed wound healing Correct answer.
  4. Excessive bleeding due to platelet dysfunction

Explanation

Vitamin C is required for the hydroxylation of proline and lysine in collagen, and deficiency impairs collagen synthesis, leading to delayed wound healing and fragile tissues. It does not directly cause platelet dysfunction or primarily affect osteoclast function, and while it supports immune function, the primary effect on healing is through collagen.

Question 50Applied Basic Sciences (Anatomy, Physiology, Pathology, Microbiology)

A patient with a history of myocardial infarction is on aspirin and clopidogrel. He requires extraction of a periodontally involved tooth. Which of the following is the most appropriate management?

  1. Stop both antiplatelet agents 7 days before surgery
  2. Continue dual antiplatelet therapy and use local hemostatic measures Correct answer.
  3. Refer the patient for coronary artery bypass surgery before extraction
  4. Stop clopidogrel only and continue aspirin

Explanation

For patients on dual antiplatelet therapy, especially those with recent coronary stents, discontinuing therapy increases the risk of stent thrombosis and cardiovascular events. Simple extractions can be safely performed with local hemostatic measures such as suturing and pressure. Stopping either agent should be done only after cardiology consultation.