Dental MCQ
Filling and sealing · Endodontics · INBDE Patient Cases

Obturation & the Coronal Seal INBDE Patient Cases

By Dr. Isaac Sun, DDS

7 ADA INBDE-format patient cases on obturation & the coronal seal. 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 endodontic obturation and the coronal seal: a well-obturated tooth that fails from coronal leakage under a broken-down temporary, an underfilled and voided canal that will not heal, gutta-percha overextended past the apex causing foreign-body irritation, choosing warm vertical condensation for a canal with lateral anatomy, verifying master-cone tug-back and length before obturation, the role and thin-film selection of endodontic sealers including bioceramic single-cone, and the prompt definitive restoration and cuspal coverage that maintain the coronal seal of a root-treated molar. Topics include obturation goals, gutta-percha and sealers, lateral and warm vertical compaction, intracanal medicaments, and the coronal seal that keeps a canal sealed.

Case Coverage Map
What each case is testing
A great-looking root canal that failed anyway:
Coronal leakage as a failure cause, the two-part (apical plus coronal) seal, prompt definitive restoration, retreatment, and gutta-percha removability.
A short, patchy-looking fill that won't heal:
Underfilling and voids as leakage paths, the dependence on cleaning and shaping, retreatment, and the role of master-cone tug-back.
Filling material pushed past the root tip:
Overextension and foreign-body irritation, lost working length and apical stop, conservative management, and overfilling versus underfilling.
A canal with lots of side branches:
Warm vertical condensation for lateral anatomy, the universal need for sealer, lateral compaction and single-cone strengths, and the shared dense-to-length goal.
Checking the cone before filling:
Tug-back and the cone-fit radiograph, verifying length before obturation, the dry-canal requirement, and seating to the apical constriction.
What the sealer is actually for:
The sealer filling gaps and lateral anatomy, the thin-film principle, bioceramic single-cone, sealer chemistries, and why bulk sealer leaks.
What to do the day the root canal finishes:
Prompt definitive restoration for the coronal seal, the risk of a long-term temporary, cuspal coverage of the root-treated molar, and the handoff to the restorative-decision module.
Patient case: A great-looking root canal that failed anyway
0 of 5 answered, 0 correct
Patient
Male, 46 years old
Chief Complaint
"The tooth I had a root canal on is acting up again."
Background and/or Patient History
  • Root canal completed last year with a radiographically dense, well-extended fill
  • A temporary restoration was left in place for many months and now looks broken down and stained
  • A new apical lesion has appeared
Allergies
NKDA
Medications
  • None
Current Findings
  • Radiographically good obturation but a leaking, broken-down coronal seal
  • New apical radiolucency; tender to percussion
  1. Question 1
    Moderate
    Despite the good apical fill, the most likely cause of failure here is:
  2. Question 2
    Moderate
    This case illustrates that long-term success requires:
  3. Question 3
    Moderate
    What should have been done after obturation to prevent this?
  4. Question 4
    Moderate
    Because the canal was recontaminated, appropriate management now is generally:
  5. Question 5
    Moderate
    The fact that gutta-percha can be removed makes this retreatment:

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Patient case: A short, patchy-looking fill that won't heal
0 of 5 answered, 0 correct
Patient
Female, 53 years old
Chief Complaint
Persistent tenderness in a previously root-treated molar.
Background and/or Patient History
  • Prior root canal; the tooth never fully settled
  • The fill stops well short of the apex and looks patchy
  • An apical lesion persists
Allergies
NKDA
Medications
  • None
Current Findings
  • Radiograph shows an underfilled canal with voids and a fill short of working length
  • Persistent apical radiolucency
  1. Question 1
    Moderate
    An underfilled canal predisposes to failure because it:
  2. Question 2
    Moderate
    The voids visible in the fill are problematic because they:
  3. Question 3
    Moderate
    The underlying reason for this poor fill is often:
  4. Question 4
    Moderate
    Appropriate management of this persistent lesion is:
  5. Question 5
    Moderate
    A snug master cone with tug-back at working length would have helped ensure:

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Patient case: Filling material pushed past the root tip
0 of 5 answered, 0 correct
Patient
Male, 39 years old
Chief Complaint
Lingering discomfort after a recent root canal.
Background and/or Patient History
  • Recent obturation; the radiograph shows gutta-percha and sealer extending past the apex
  • Persistent mild periapical tenderness
  • The working length was likely lost, allowing overextension
Allergies
NKDA
Medications
  • None
Current Findings
  • Gutta-percha and sealer extruded beyond the radiographic apex
  • Mild periapical tenderness; no spreading infection
  1. Question 1
    Moderate
    Material extruded past the apex can:
  2. Question 2
    Moderate
    The most likely technical reason for overextension is:
  3. Question 3
    Hard
    Preserving an apical stop at the constriction during shaping helps prevent overextension because it:
  4. Question 4
    Moderate
    If the periapical tenderness is mild and there is no spreading infection, reasonable management is:
  5. Question 5
    Moderate
    Compared with underfilling, overfilling differs in that it:

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Patient case: A canal with lots of side branches
0 of 5 answered, 0 correct
Patient
Female, 34 years old
Chief Complaint
Root canal on a tooth with complex canal anatomy.
Background and/or Patient History
  • A well-cleaned canal shown to have lateral (accessory) canals and irregularities
  • The clinician is selecting an obturation technique
  • Goal is a three-dimensional fill that adapts to the anatomy
Allergies
NKDA
Medications
  • None
Current Findings
  • Irregular canal with visible lateral anatomy
  • Canal cleaned, shaped, and dry, ready to fill
  1. Question 1
    Moderate
    Which technique best adapts the fill into lateral canals and irregularities?
  2. Question 2
    Moderate
    Regardless of the technique chosen, a sealer is used because gutta-percha:
  3. Question 3
    Moderate
    If lateral compaction were chosen instead, its main strength would be:
  4. Question 4
    Moderate
    A single-cone approach here would rely heavily on:
  5. Question 5
    Easy
    Whatever technique is selected, the shared objective is:

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Patient case: Checking the cone before filling
0 of 5 answered, 0 correct
Patient
Male, 41 years old
Chief Complaint
Root canal nearing the obturation stage.
Background and/or Patient History
  • Canal cleaned, shaped, disinfected, and dry
  • A master gutta-percha cone is being fitted before obturation
  • The clinician checks the fit and confirms with a radiograph
Allergies
NKDA
Medications
  • None
Current Findings
  • Master cone seats to working length with slight resistance to withdrawal
  • Cone-fit radiograph confirms the cone at length
  1. Question 1
    Moderate
    The slight resistance felt when withdrawing the well-fitted master cone is called:
  2. Question 2
    Moderate
    The purpose of the cone-fit radiograph is to:
  3. Question 3
    Moderate
    Verifying cone fit and length before obturation helps prevent:
  4. Question 4
    Moderate
    The fact that the canal is dry before obturation matters because:
  5. Question 5
    Moderate
    Confirming the cone is at the apical constriction (not beyond) supports:

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Patient case: What the sealer is actually for
0 of 5 answered, 0 correct
Patient
Female, 48 years old
Chief Complaint
Routine obturation; the clinician selects a sealer.
Background and/or Patient History
  • A well-shaped canal ready to fill
  • The clinician is choosing and applying an endodontic sealer with the gutta-percha
  • Planning a single-cone obturation
Allergies
NKDA
Medications
  • None
Current Findings
  • Canal shaped to a matched taper, clean and dry
  • Bioceramic sealer being considered
  1. Question 1
    Moderate
    The primary role of the sealer is to:
  2. Question 2
    Moderate
    The sealer should be applied as:
  3. Question 3
    Moderate
    A bioceramic (calcium silicate) sealer is especially associated with which technique?
  4. Question 4
    Moderate
    Other recognized sealer chemistries include:
  5. Question 5
    Moderate
    Excess sealer used as the bulk of the fill is undesirable because it can:

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Patient case: What to do the day the root canal finishes
0 of 5 answered, 0 correct
Patient
Male, 57 years old
Chief Complaint
Root canal just completed on a posterior molar.
Background and/or Patient History
  • Obturation finished on a heavily restored molar that lost both marginal ridges
  • Patient asks whether the temporary filling is enough
  • Planning the definitive restoration
Allergies
NKDA
Medications
  • None
Current Findings
  • Dense obturation to length; a temporary restoration currently in place
  • Significant coronal structure already lost
  1. Question 1
    Moderate
    To protect the result, the definitive restoration should be placed:
  2. Question 2
    Moderate
    Relying on the temporary restoration long-term would risk:
  3. Question 3
    Moderate
    Given the lost marginal ridges on this posterior molar, the restorative plan will likely involve:
  4. Question 4
    Moderate
    This case shows that the endodontic and restorative plans are:
  5. Question 5
    Easy
    The detailed decision about how to restore and protect this tooth is covered in:

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Keep studying
Obturation & the Coronal Seal core recall

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

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