Dental MCQ
Nerve blocks, sinus pain, facial spaces, and orofacial pain · Head & Neck · INBDE Patient Cases

Clinical Applications INBDE Patient Cases

By Dr. Isaac Sun, DDS

12 ADA INBDE-format patient cases on clinical applications. Each case is a shared patient box (chief complaint, history, medications, allergies, exam) followed by linked multiple-choice questions with full distractor explanations. Practice the way the real exam is structured.

12 patient cases60 linked questionsADA INBDE formatFull distractor explanations

Twelve ADA INBDE-format patient cases on clinical head and neck anatomy: nerve block complications (mylohyoid accessory innervation, a fractured anesthetic needle in the pterygomandibular space, transient facial nerve paralysis from parotid diffusion), facial pain syndromes (trigeminal neuralgia mimicking a cracked tooth, persistent dentoalveolar pain after a technically successful root canal), odontogenic fascial-space infections (Ludwig's angina from a mandibular molar, orbital cellulitis from a maxillary canine via the canine fossa, a buccal space abscess from a maxillary molar, a masticator space abscess with severe trismus from a lower third molar, and oroantral communication after a maxillary molar extraction), odontogenic maxillary sinusitis referred as upper toothache, and a submandibular sialolith obstructing Wharton's duct.

Case Coverage Map
What each case is testing
Failed IAN block on #19:
Mylohyoid accessory innervation, lingual articaine rescue, Gow-Gates as backup.
Anesthetic needle breaks during an IAN block:
Fragment in the pterygomandibular space, keep the mouth open, image and refer; 25-gauge prevention.
Transient facial droop after an IAN block:
CN VII anesthesia from parotid diffusion, hemifacial weakness as LMN pattern, corneal protection.
Electric V2 pain mistaken for a cracked tooth:
Trigeminal neuralgia, carbamazepine first-line, avoiding irreversible dental treatment.
Atypical odontalgia after a successful RCT:
Persistent dentoalveolar pain (PDAP), neuropathic mechanism, stopping the chase for a dental cause.
Ludwig's angina from a neglected #19:
Submandibular/sublingual/submental spread, airway-first management, polymicrobial coverage.
Orbital cellulitis from an infected #11:
Canine fossa → infraorbital → orbit route, postseptal versus preseptal, vision-threatening surgical indications.
Cheek swelling from an infected upper molar:
Buccal space versus the dangerous spaces, the buccinator-apex rule, source control.
Oroantral communication after #14:
Schneiderian membrane perforation, conservative versus surgical closure, pre-op CBCT.
Severe trismus from an infected lower wisdom tooth:
Masticator space abscess, masseter and medial pterygoid trismus, parapharyngeal red flags.
Upper tooth ache with a foul, stuffy nose:
Maxillary sinusitis referred via V2, multi-tooth versus pulpal pain, odontogenic source.
Floor-of-mouth swelling that flares at meals:
Submandibular sialolith in Wharton's duct, lingual nerve relationship, conservative care.
Patient case: Failed IAN block on #19 (accessory innervation)
0 of 5 answered, 0 correct
Patient
Female, 34 years old
Chief Complaint
"I came in for the filling on the lower left, but I can still feel the drill."
Background and/or Patient History
  • Presents for occlusal composite on #19
  • IAN block with 2% lidocaine and 1:100,000 epinephrine performed
  • Second IAN at the same site produced the same result
  • Medical history unremarkable
Allergies
NKDA
Medications
  • None
Dental History
  • Routine maintenance
  • Small occlusal caries on #19 (bitewing)
Current Findings
  • Profound numbness of left lower lip, chin, and tongue
  • #19 still tests hot
  • Cold reproduces sharp pain on #19
  • No swelling
  • No periapical pathology on PA
  1. Question 1
    Easy
    With a numb lip and tongue but a still-hot #19, the most likely explanation is:
  2. Question 2
    Moderate
    The mylohyoid nerve typically branches from the IAN:
  3. Question 3
    Moderate
    The most reliable supplemental injection for the mylohyoid contribution is:
  4. Question 4
    Hard
    If lingual infiltration also fails, the next technique is:
  5. Question 5
    Moderate
    A key reason 4% articaine outperforms lidocaine for mandibular infiltration is:

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Patient case: Anesthetic needle breaks during an IAN block
0 of 5 answered, 0 correct
Patient
Male, 29 years old
Chief Complaint
"The needle snapped during my numbing shot and you said part of it is still in there."
Background and/or Patient History
  • Presented for extraction of tooth #18
  • Sudden patient movement during a standard IAN block
  • A 30-gauge short needle separated at the hub
  • Anxious, first dental surgery
  • Otherwise healthy
Allergies
NKDA
Medications
  • None
Dental History
  • Prior cleanings only, no surgery
  • Reports a strong gag and needle phobia
Current Findings
  • Patient calm now, airway patent
  • No bleeding from the injection site
  • Mild discomfort deep to the right ramus
  • Needle fragment not visible or palpable intraorally
  • Mouth opening preserved
  1. Question 1
    Easy
    A 30-gauge needle is more prone to fracture during an IAN block mainly because it is:
  2. Question 2
    Moderate
    An IAN-block needle that separates most likely lodges in which space?
  3. Question 3
    Moderate
    The most appropriate immediate step is to:
  4. Question 4
    Moderate
    For a fragment that is not visible, the appropriate next step is:
  5. Question 5
    Hard
    The single best technique change to prevent needle breakage is to:

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Patient case: Transient facial droop after an IAN block
0 of 5 answered, 0 correct
Patient
Male, 41 years old
Chief Complaint
"You numbed me up for the back tooth and now I can't close my right eye."
Background and/or Patient History
  • Presented for endodontic access on #30
  • Right IAN block administered 8 minutes ago
  • Patient noticed inability to close the right eye and right-sided facial droop within minutes
  • No prior neurologic history
Allergies
NKDA
Medications
  • None
Dental History
  • Previous IAN blocks uneventful
Current Findings
  • Right-sided upper and lower facial weakness (cannot wrinkle forehead, cannot close eye, drooping commissure)
  • Normal sensation of right cheek and lip
  • No ear pain, vesicles, or hearing change
  • Mandibular teeth profoundly anesthetized on the right
  • Otherwise neurologically intact
  1. Question 1
    Easy
    The most likely cause of the facial droop is:
  2. Question 2
    Moderate
    Both forehead and lower face are weak because:
  3. Question 3
    Moderate
    The single most important immediate dental management step is:
  4. Question 4
    Easy
    Expected recovery is:
  5. Question 5
    Moderate
    The technical adjustment that prevents this complication is:

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Patient case: Electric V2 pain mistaken for a cracked tooth
0 of 5 answered, 0 correct
Patient
Female, 62 years old
Chief Complaint
"It feels like a lightning bolt in my upper jaw whenever the wind hits my cheek or I brush my teeth."
Background and/or Patient History
  • Two months of episodic right-sided facial pain
  • Sharp, electric, lasting seconds, then disappearing completely
  • Triggered by light touch of the cheek, brushing, chewing on the right
  • No throbbing background pain between episodes
  • Sleep is undisturbed
  • Has seen two dentists; #3 was treated endodontically without improvement
Allergies
NKDA
Medications
  • Atorvastatin
  • Hydrochlorothiazide
Dental History
  • Endodontic therapy on #3 one month ago: clinical and radiographic success but no pain relief
  • All other right maxillary teeth vital, non-tender, no caries
Current Findings
  • All vital signs normal
  • No facial swelling
  • Right cheek light touch reproduces a 5-second lancinating pain in the V2 distribution
  • Pulp tests on #2, #4, #5 within normal limits
  • No percussion tenderness
  • Cranial nerve exam otherwise intact
  1. Question 1
    Easy
    The most likely diagnosis is:
  2. Question 2
    Moderate
    The classic peripheral mechanism of classical TN is:
  3. Question 3
    Easy
    First-line medical therapy is:
  4. Question 4
    Moderate
    The single most important dental management point is:
  5. Question 5
    Hard
    If carbamazepine ultimately fails or is not tolerated, the next step is:

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Patient case: Atypical odontalgia after a successful RCT
0 of 5 answered, 0 correct
Patient
Female, 47 years old
Chief Complaint
"My tooth has been hurting non-stop since the root canal six months ago, but every dentist tells me it looks fine."
Background and/or Patient History
  • Endodontic therapy on #14 six months ago for vital pulp with deep restoration
  • Procedure technically uneventful, radiographic healing complete
  • Continuous, dull, deep aching in #14 area since the procedure
  • Pain is constant background, no thermal triggers, not relieved by NSAIDs
  • Two retreatments and an apicoectomy have not helped
  • Patient is anxious, sleep is disrupted, considering extraction
Allergies
NKDA
Medications
  • Sertraline (for depression/anxiety)
Dental History
  • Multiple restorations, all otherwise asymptomatic
  • #14: RCT, retreatment x2, apicoectomy, all radiographically successful
Current Findings
  • Vital signs normal
  • #14 non-tender to percussion, palpation, biting
  • No swelling, no sinus tract
  • Adjacent teeth normal pulp tests
  • PA, CBCT: no residual pathology, complete osseous healing
  • Local anesthetic infiltration at #14 only partially reduces pain (incomplete LA test)
  1. Question 1
    Moderate
    The most likely diagnosis is:
  2. Question 2
    Moderate
    The underlying mechanism is best described as:
  3. Question 3
    Easy
    The most important next step in management is:
  4. Question 4
    Moderate
    Typical first-line pharmacologic options include:
  5. Question 5
    Moderate
    Counseling the patient should include:

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Patient case: Ludwig's angina from a neglected #19
0 of 5 answered, 0 correct
Patient
Male, 47 years old
Chief Complaint
"I've had a toothache for a week, and now my tongue feels pushed up and I can barely swallow."
Background and/or Patient History
  • Transferred from a general dental office to the ED
  • Rapidly progressive bilateral submandibular swelling over 36 hours
  • Drooling, hot-potato voice, pain on tongue movement
  • Has not slept lying flat for two nights
  • Symptoms began as throbbing pain in #19, untreated for months
  • Type 2 diabetes (HbA1c 9.3, poorly controlled)
Allergies
NKDA
Medications
  • Metformin (poor compliance)
Dental History
  • Last cleaning more than five years ago
  • Generalized untreated caries
  • PA shows large periapical radiolucency at #19
Current Findings
  • BP not recorded
  • HR 112
  • RR 22
  • Temp 38.7 C
  • SpO2 94 percent on room air, trending down
  • Brawny bilateral submandibular and submental swelling
  • Tongue elevated against palate
  • Trismus
  • Drooling
  1. Question 1
    Easy
    The most likely diagnosis is:
  2. Question 2
    Moderate
    Ludwig's involves which three fascial spaces?
  3. Question 3
    Hard
    Mandibular second molars are the classic source because:
  4. Question 4
    Hard
    The single most important initial priority is:
  5. Question 5
    Moderate
    Empiric antibiotic therapy should target:

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Patient case: Orbital cellulitis from an infected #11
0 of 5 answered, 0 correct
Patient
Male, 33 years old
Chief Complaint
"My left eye is swelling shut and I can't see straight, but the tooth pain has been going on for two weeks."
Background and/or Patient History
  • Two weeks of throbbing pain in the left upper canine area, untreated
  • Three days of progressive left periorbital swelling, erythema
  • Today: diplopia, pain with eye movement, mild fever
  • Otherwise healthy, no immunosuppression
Allergies
NKDA
Medications
  • None
Dental History
  • #11 large carious lesion with prior intermittent pain
  • PA: large periapical radiolucency at #11 apex
  • No regular dental care
Current Findings
  • Temp 38.5 C, HR 102
  • Left periorbital swelling, erythema extending from upper lip to brow
  • Proptosis (left eye)
  • Pain on left eye movement, restricted upward gaze
  • Visual acuity preserved at this point
  • Pupillary responses normal
  • #11 grossly carious, percussion-tender, mobile
  1. Question 1
    Easy
    The most likely diagnosis is:
  2. Question 2
    Moderate
    The anatomic route from #11 to the orbit is:
  3. Question 3
    Easy
    The single most important next step is:
  4. Question 4
    Hard
    Findings that would push management toward urgent surgical drainage rather than IV antibiotics alone include:
  5. Question 5
    Moderate
    The most concerning intracranial complication if untreated is:

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Patient case: Cheek swelling from an infected upper molar
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Patient
Male, 44 years old
Chief Complaint
"My upper back tooth has ached for a week and now my cheek is swollen."
Background and/or Patient History
  • Throbbing pain from the upper right molar region for about a week
  • Cheek swelling over the past 2 days
  • Low-grade fever
  • No eye swelling, no trouble swallowing or breathing
  • Tooth never treated
Allergies
NKDA
Medications
  • None
Dental History
  • Irregular care
  • Large carious lesion on #3
Current Findings
  • Temp 37.9 C, HR 88
  • Diffuse soft swelling of the right cheek, below the zygoma
  • Floor of mouth and eye uninvolved
  • #3 grossly carious, percussion-tender, non-vital on pulp testing
  • Mouth opening near normal, airway patent
  1. Question 1
    Easy
    Cheek swelling from an infected maxillary molar most likely occupies the:
  2. Question 2
    Moderate
    Whether a molar abscess points into the mouth or into the buccal space depends on the apex position relative to the:
  3. Question 3
    Moderate
    Which feature most reassures you this is a buccal space infection and not a dangerous space?
  4. Question 4
    Moderate
    Appropriate management for this stable, healthy patient is:
  5. Question 5
    Hard
    Which new finding would change management to urgent hospital referral?

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Patient case: Oroantral communication after #14 extraction
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Patient
Male, 52 years old
Chief Complaint
"Ever since you pulled the top molar, when I drink water some of it comes out of my nose."
Background and/or Patient History
  • One week post routine extraction of #14
  • Postoperative socket did not seal well
  • Reports salty-tasting nasal drainage
  • Left-sided cheek fullness
  • Air whistling through the socket on cheek puff
  • No fever
  • Hypertension, controlled
Allergies
NKDA
Medications
  • Lisinopril
Dental History
  • #14 had a large failing crown with periapical pathology
  • Pre-op PA showed long divergent roots extending into the sinus floor
Current Findings
  • Vitals normal
  • Socket #14 with a 3 mm defect at the floor
  • Positive Valsalva (bubbling through the socket)
  • Left maxillary sinus tender
  • No frank pus
  1. Question 1
    Easy
    The most likely diagnosis is:
  2. Question 2
    Moderate
    The thin membrane between the sinus and oral cavity at the molar apices is the:
  3. Question 3
    Moderate
    For a 3 mm OAC with no purulence, the appropriate management is:
  4. Question 4
    Hard
    First-line antibiotic for odontogenic sinusitis with OAC is:
  5. Question 5
    Moderate
    The single most important preoperative step to reduce OAC risk is:

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Patient case: Severe trismus from an infected lower wisdom tooth
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Patient
Male, 26 years old
Chief Complaint
"My lower wisdom tooth got infected and now I can barely open my mouth."
Background and/or Patient History
  • Recurrent pericoronitis around a partially erupted #17
  • Worsening left jaw pain and swelling over 4 days
  • Progressive inability to open the mouth
  • Low-grade fever and malaise
  • Still able to swallow and breathe
Allergies
NKDA
Medications
  • Ibuprofen as needed
Dental History
  • Partially erupted #17 with an inflamed operculum
  • Episodes of pericoronitis over the past year
Current Findings
  • Temp 38.2 C
  • Marked trismus, maximum opening 12 mm
  • Swelling and tenderness over the left angle and masseter
  • Pericoronal erythema and pus around #17
  • Floor of mouth soft, tongue not elevated, airway patent
  1. Question 1
    Easy
    Severe trismus with angle and masseter swelling from a lower third molar localizes to the:
  2. Question 2
    Moderate
    The severe trismus is produced by inflammation of which muscles?
  3. Question 3
    Moderate
    Trismus from a masticator space infection is distinguished from post-injection trismus by:
  4. Question 4
    Moderate
    Appropriate management is:
  5. Question 5
    Hard
    Which finding most raises concern for spread to the parapharyngeal space and airway?

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Patient case: Upper tooth ache with a stuffy, foul-smelling nose
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Patient
Female, 39 years old
Chief Complaint
"My upper back teeth ache and feel full, and one side of my nose is stuffy."
Background and/or Patient History
  • Two weeks of dull aching across the upper left posterior teeth
  • Left-sided nasal congestion with a foul discharge
  • Pain worse when bending forward
  • No fever
  • Recent deep restoration on #15
Allergies
NKDA
Medications
  • None
Dental History
  • Deep composite on #15 a month ago
  • No other recent work
Current Findings
  • Several left maxillary posterior teeth tender to percussion, not isolated to one
  • #15 vital with brief cold response; #14 and #16 vital and non-tender
  • Pain reproduced by bending forward and pressing the left cheek
  • Purulent discharge from the left middle meatus
  • PA: intact lamina dura with thickened left sinus mucosa near the #15 apex
  1. Question 1
    Easy
    The most likely cause of her diffuse upper posterior tooth pain is:
  2. Question 2
    Moderate
    The maxillary posterior teeth and the sinus floor share sensory supply from:
  3. Question 3
    Moderate
    Which finding best separates sinus-referred pain from a true pulpal source?
  4. Question 4
    Moderate
    Appropriate management is:
  5. Question 5
    Hard
    Which scenario would instead point to odontogenic (dental-origin) maxillary sinusitis?

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Patient case: Floor-of-mouth swelling that flares at every meal
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Patient
Female, 51 years old
Chief Complaint
"The floor of my mouth swells and aches every time I eat, then it settles."
Background and/or Patient History
  • Recurrent left submandibular swelling and pain at mealtimes for 2 months
  • Swelling subsides between meals
  • Occasional gritty sensation under the tongue
  • No fever currently
  • No skin redness over the gland
Allergies
NKDA
Medications
  • None
Dental History
  • Routine care
  • No recent dental work
Current Findings
  • Tender, enlarged left submandibular gland that swells with a lemon-drop
  • Reduced saliva from the left Wharton duct orifice
  • A hard nodule palpable along the floor of mouth at the duct
  • Occlusal radiograph: radiopaque stone in the left floor of mouth
  • No trismus, airway patent
  1. Question 1
    Easy
    Mealtime gland swelling with a stone in the floor of mouth indicates obstruction of:
  2. Question 2
    Moderate
    Most salivary stones form in the submandibular gland because its secretion and duct are:
  3. Question 3
    Moderate
    Removing a floor-of-mouth stone most endangers which structure crossing Wharton's duct?
  4. Question 4
    Moderate
    Initial management of a small, palpable distal duct stone is:
  5. Question 5
    Hard
    Which development would shift management toward urgent antibiotics or referral?

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