Dental MCQ
Joint and movement · Occlusion · INBDE Patient Cases

TMJ & Mandibular Movements INBDE Patient Cases

By Dr. Isaac Sun, DDS

7 ADA INBDE-format patient cases on tmj & mandibular movements. 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.

7 patient cases35 linked questionsADA INBDE formatFull distractor explanations

Seven ADA INBDE-format patient cases on the TMJ and mandibular movement: the rotation-then-translation pattern of opening with the disc dividing the joint into upper (translation) and lower (rotation) compartments, disc displacement with reduction (clicking) managed conservatively for asymptomatic patients, acute closed lock with sudden ~25 mm opening limit and deviation toward the affected side managed with conservative care and arthrocentesis/arthroscopy/open surgery for refractory cases, TMJ osteoarthritis with crepitus and characteristic radiographic degenerative changes, working vs non-working side distinction with Bennett movement and the 7-15° Bennett angle and the mutually-protected canine disocclusion of posterior teeth bilaterally, the joint-determined posterior (condylar) guidance versus the tooth-determined and restorable anterior guidance inside Hanau's quint of articulator inputs, and Posselt's envelope with the CR-CO slide and centric relation as a reproducible joint reference for prosthodontic articulator mounting. Topics include TMJ anatomy, mandibular movement, hinge axis, Posselt's envelope, working vs non-working side, Bennett movement and angle, and the determinants of mandibular movement.

Case Coverage Map
What each case is testing
Rotation, then translation, during mouth opening:
First ~25 mm is rotation in the lower compartment; beyond that adds translation along the eminence; TMJ surfaces are fibrocartilage; normal opening 40-55 mm.
Disc displacement with reduction (clicking):
Opening (± closing) click as the condyle moves under the displaced disc; conservative management of asymptomatic clicking; MRI if intra-articular pathology suspected.
Acute closed lock (disc displacement without reduction):
Sudden ~25 mm limit, deviation toward the affected side, click disappears; conservative care first; arthrocentesis/arthroscopy/open surgery for refractory cases.
TMJ osteoarthritis with crepitus:
Crepitus + joint space narrowing + condylar flattening + osteophytes; conservative TMD/OA care; surgery rare; differential with RA.
Working vs non-working side in lateral movement:
Working side = side moved toward; non-working condyle translates forward/downward/medially; Bennett angle 7-15°; canine disocclusion bilateral.
Anterior vs condylar guidance:
Condylar guidance joint-determined and fixed; anterior guidance tooth-determined and restorable; Hanau quint inputs in articulator setup.
Posselt's envelope and the CR-CO slide:
Sagittal-plane border outline; CR is joint-determined and independent of tooth contact; CR-CO slide is the short anterior-superior movement; CR records mount articulators.
Patient case: Rotation, then translation, during mouth opening
0 of 5 answered, 0 correct
Patient
Female, 40 years old
Chief Complaint
Routine examination with comfortable maximum opening of 48 mm.
Background and/or Patient History
  • Healthy patient; no joint symptoms
  • Maximum interincisal opening 48 mm (normal)
  • Discussion of how the mandible opens
Allergies
NKDA
Medications
  • None
Current Findings
  • Normal mandibular opening pattern
  1. Question 1
    Moderate
    The FIRST ~20-25 mm of opening is predominantly:
  2. Question 2
    Moderate
    Beyond ~25 mm, opening adds:
  3. Question 3
    Moderate
    The articular surfaces of the TMJ are:
  4. Question 4
    Easy
    Normal MAXIMUM interincisal opening in adults is approximately:
  5. Question 5
    Easy
    The teaching point is that the TMJ:

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Patient case: Disc displacement with reduction (clicking)
0 of 5 answered, 0 correct
Patient
Female, 28 years old
Chief Complaint
Painless clicking of the right TMJ on opening for several months.
Background and/or Patient History
  • Right TMJ click on opening (and softer click on closing)
  • Maximum interincisal opening 48 mm
  • No restriction; no constant pain
Allergies
NKDA
Medications
  • None
Current Findings
  • Disc displacement with reduction (anterior disc displacement that reduces during opening)
  1. Question 1
    Moderate
    The clicking pattern (opening click ± closing click; opening preserved) describes:
  2. Question 2
    Hard
    The mechanism of the opening click is:
  3. Question 3
    Moderate
    First-line management of asymptomatic disc displacement with reduction is:
  4. Question 4
    Moderate
    If pain or restriction develops, the next step is:
  5. Question 5
    Easy
    The teaching point is that TMJ clicking:

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Patient case: Acute closed lock (disc displacement without reduction)
0 of 5 answered, 0 correct
Patient
Male, 35 years old
Chief Complaint
Sudden inability to open the mouth past ~25 mm; previous intermittent right TMJ clicking that has now disappeared.
Background and/or Patient History
  • History of right TMJ clicking
  • Sudden onset of limited opening to ~25 mm; click is gone
  • Pain on attempted opening; deviation to the right
Allergies
NKDA
Medications
  • Ibuprofen PRN
Current Findings
  • Acute closed lock (disc displacement without reduction)
  1. Question 1
    Moderate
    Sudden limited opening (~25 mm), deviation to the affected side, and loss of the prior click describe:
  2. Question 2
    Hard
    The mandibular DEVIATION on attempted opening goes:
  3. Question 3
    Moderate
    First-line management of acute closed lock is:
  4. Question 4
    Hard
    If conservative care fails over weeks to months, options include:
  5. Question 5
    Easy
    The teaching point is that closed lock:

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Patient case: TMJ osteoarthritis with crepitus
0 of 5 answered, 0 correct
Patient
Female, 70 years old
Chief Complaint
Bilateral TMJ grinding sound on jaw movement for years; mild morning stiffness.
Background and/or Patient History
  • Long history of bilateral TMJ crepitus (grinding/grating)
  • Mild morning stiffness; otherwise functional
  • Radiograph shows joint space narrowing and condylar flattening
Allergies
NKDA
Medications
  • Acetaminophen PRN
Current Findings
  • TMJ osteoarthritis (degenerative joint disease)
  1. Question 1
    Moderate
    Crepitus (grinding sound on joint movement) suggests:
  2. Question 2
    Moderate
    Radiographic findings of TMJ OA include:
  3. Question 3
    Moderate
    Management is:
  4. Question 4
    Hard
    Rheumatoid arthritis of the TMJ differs from OA in that RA:
  5. Question 5
    Easy
    The teaching point of TMJ OA is that:

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Patient case: Working vs non-working side in lateral movement
0 of 5 answered, 0 correct
Patient
Mixed (educational case)
Chief Complaint
Conceptual case on lateral movement and the Bennett angle.
Background and/or Patient History
  • Discussion of working vs non-working side, Bennett movement, and Bennett angle
  • How these set posterior tooth disocclusion in lateral movements
Allergies
NKDA
Medications
  • None
Current Findings
  • Conceptual lateral movement case
  1. Question 1
    Moderate
    When the mandible moves laterally toward the LEFT, the WORKING (laterotrusive) side is:
  2. Question 2
    Moderate
    On the NON-WORKING side, the condyle:
  3. Question 3
    Moderate
    The BENNETT ANGLE is approximately:
  4. Question 4
    Moderate
    In MUTUALLY PROTECTED occlusion, during left lateral movement, the LEFT canine should:
  5. Question 5
    Easy
    The teaching point of working vs non-working sides is:

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Patient case: Anterior vs condylar guidance
0 of 5 answered, 0 correct
Patient
Female, 45 years old
Chief Complaint
Planning full-mouth rehabilitation; discussion of how the new restorations will guide the mandible.
Background and/or Patient History
  • Generalized wear from chronic bruxism
  • Full-mouth rehabilitation planned
  • Articulator setup discussion
Allergies
NKDA
Medications
  • None notable
Current Findings
  • Need to set up anterior guidance in restorative reconstruction
  1. Question 1
    Moderate
    POSTERIOR (CONDYLAR) GUIDANCE is:
  2. Question 2
    Moderate
    ANTERIOR GUIDANCE is:
  3. Question 3
    Hard
    In articulator setup, condylar guidance is recorded with a:
  4. Question 4
    Hard
    In a full-mouth rehabilitation, the dentist primarily controls:
  5. Question 5
    Easy
    The teaching point is that occlusal reconstruction:

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Patient case: Posselt's envelope and the CR-CO slide
0 of 5 answered, 0 correct
Patient
Male, 50 years old
Chief Complaint
Routine prosthodontic workup; discussion of where to record the bite.
Background and/or Patient History
  • Pre-prosthetic planning
  • Discussion of Posselt's envelope and the CR-CO slide
Allergies
NKDA
Medications
  • None
Current Findings
  • Conceptual prosthodontic case
  1. Question 1
    Moderate
    POSSELT'S ENVELOPE is:
  2. Question 2
    Moderate
    The CR-CO SLIDE is:
  3. Question 3
    Moderate
    CENTRIC RELATION is best characterized as:
  4. Question 4
    Moderate
    CR records support:
  5. Question 5
    Easy
    The teaching point of CR and Posselt's envelope is that:

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TMJ & Mandibular Movements core recall

Refresh the anatomy facts these cases depend on: nerve numbers, foramina, functions, and lesion findings.

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