Dental MCQ
Will the tooth survive? · Endodontics · INBDE Patient Cases

Restore, Retreat, or Extract INBDE Patient Cases

By Dr. Isaac Sun, DDS

8 ADA INBDE-format patient cases on restore, retreat, or extract. 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.

8 patient cases40 linked questionsADA INBDE formatFull distractor explanations

Eight ADA INBDE-format patient cases on the endodontic restorative decision, framed by the Structural Decision Framework: a root-treated molar with minimal structure where the ferrule (not a post) decides survival, counseling that a post only retains a core, cuspal coverage of a weakened posterior endo tooth under bruxism, a vertical root fracture recognized by a deep narrow pocket and J-shaped radiolucency and managed by extraction, weighing nonsurgical retreatment versus apical surgery versus extraction for a failing tooth, conservative restoration of an intact anterior endo tooth, coronal-leakage failure from a delayed definitive restoration, and an integrated synthesis running Structure, Force, Time, and Stability. Topics include the ferrule effect, post-and-core indications, cuspal coverage, vertical root fracture, and the retreat-versus-extract decision.

Case Coverage Map
What each case is testing
A root-canaled molar with almost nothing left:
The ferrule and restorability (Structure/Stability), post does not strengthen, crown lengthening or extrusion to gain a ferrule, and extraction when the prognosis stays poor.
"Will a post make my tooth stronger?":
Counseling that a post only retains a core, the ferrule predicts survival, avoiding an unnecessary post, and the prompt coronal seal.
A root-canaled molar with no marginal ridges left:
Cuspal coverage of the weakened posterior endo tooth (Force lens with bruxism), the source of structural loss, the intact-anterior contrast, and the prosthodontic handoff.
A deep narrow pocket and a halo on the x-ray:
Vertical root fracture signs, why it is unrestorable and extracted, the post's role in fracture (Force), poor stability, and prosthodontic replacement.
Weighing retreat, surgery, or extraction:
Nonsurgical retreatment first when re-accessible (Time), apical surgery if it fails, when extraction wins, and the factors weighed.
A treated front tooth that's basically intact:
Conservative restoration of the intact anterior endo tooth (Structure), matching restoration to structure, the coronal seal, and the broken-down contrast.
A canal left under a temporary too long:
Coronal-leakage failure and the Time lens on a delayed restoration, prompt definitive restoration, retreatment, and the endo-restorative link.
Running all four lenses on one tooth:
An SDF synthesis: Structure (ferrule), Force (bruxism, coverage), Time (retreat the lesion), and Stability (the integrated ten-year plan).
Patient case: A root-canaled molar with almost nothing left
0 of 5 answered, 0 correct
Patient
Male, 54 years old
Chief Complaint
"Can this tooth even be saved, or should it come out?"
Background and/or Patient History
  • Root canal completed on a molar with extensive prior decay
  • Very little sound coronal tooth structure remains above the gumline
  • Patient asks whether a post and crown will save it
Allergies
NKDA
Medications
  • None
Current Findings
  • Minimal coronal structure, little or no ferrule available
  • Otherwise adequate root length and periodontal support
  1. Question 1
    Moderate
    Through the Structure lens, the key concern is:
  2. Question 2
    Moderate
    If the patient hopes a post will strengthen the tooth, the correct counseling is:
  3. Question 3
    Hard
    With little or no ferrule available, through the Stability lens the long-term outlook for a post-and-crown is:
  4. Question 4
    Hard
    Options to gain a ferrule before committing to retain the tooth might include:
  5. Question 5
    Moderate
    If an adequate ferrule cannot be achieved and the prognosis stays poor, a reasonable plan is:

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Patient case: "Will a post make my tooth stronger?"
0 of 5 answered, 0 correct
Patient
Female, 47 years old
Chief Complaint
"My last dentist mentioned a post. Will that make the tooth stronger?"
Background and/or Patient History
  • Endodontically treated premolar with moderate remaining coronal structure
  • Patient believes a post reinforces the tooth
  • Adequate sound tooth for a ferrule is present
Allergies
NKDA
Medications
  • None
Current Findings
  • Sufficient coronal structure that the core could be retained without a post
  • A ferrule is achievable
  1. Question 1
    Moderate
    The accurate explanation about posts is that they:
  2. Question 2
    Moderate
    Because this tooth has adequate coronal structure, a post is:
  3. Question 3
    Moderate
    What actually predicts better survival of the restored tooth is:
  4. Question 4
    Moderate
    Avoiding an unnecessary post is beneficial because post space preparation:
  5. Question 5
    Moderate
    Whatever is done coronally, the canal result is protected by:

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Patient case: A root-canaled molar with no marginal ridges left
0 of 5 answered, 0 correct
Patient
Male, 50 years old
Chief Complaint
Planning the final restoration after a molar root canal.
Background and/or Patient History
  • Endodontically treated mandibular molar
  • Both marginal ridges were lost to access and prior caries
  • Patient has heavy occlusal function
Allergies
NKDA
Medications
  • None
Current Findings
  • Significant coronal structure lost; cusps relatively unsupported
  • Vital periodontal support; tooth restorable
  1. Question 1
    Moderate
    For this endodontically treated posterior tooth with lost marginal ridges, the indicated restoration is:
  2. Question 2
    Moderate
    Through the Force lens, heavy occlusal function makes coverage:
  3. Question 3
    Moderate
    The structural loss that justifies coverage here came mainly from:
  4. Question 4
    Moderate
    If this had instead been an intact anterior tooth with a small access, the plan would more likely be:
  5. Question 5
    Easy
    The fabrication of the crown itself is performed in:

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Patient case: A deep narrow pocket and a halo on the x-ray
0 of 5 answered, 0 correct
Patient
Female, 58 years old
Chief Complaint
Recurrent pain and a gum problem on a previously root-treated, posted tooth.
Background and/or Patient History
  • Root-treated tooth with a cemented post; symptoms returned after years
  • A deep, narrow, isolated periodontal pocket is found on one root surface
  • Pain on biting; a J-shaped radiolucency is seen
Allergies
NKDA
Medications
  • None
Current Findings
  • Deep narrow isolated pocket and a J-shaped (halo) radiolucency
  • Findings consistent with a vertical root fracture
  1. Question 1
    Hard
    The deep, narrow, isolated pocket with a J-shaped radiolucency and biting pain suggests:
  2. Question 2
    Moderate
    A vertical root fracture is generally:
  3. Question 3
    Hard
    Through the Force lens, a contributor to this fracture was likely:
  4. Question 4
    Moderate
    Through the Stability lens, the prognosis of this tooth is:
  5. Question 5
    Easy
    After extraction, replacing the tooth with an implant or bridge is:

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Patient case: Weighing retreat, surgery, or extraction
0 of 5 answered, 0 correct
Patient
Male, 49 years old
Chief Complaint
A previously root-treated tooth with a lesion that has not healed.
Background and/or Patient History
  • Root canal done years ago; a periapical lesion persists
  • The tooth is restorable, the canal is re-accessible, and there is no post
  • Patient wants to keep the tooth if reasonable
Allergies
NKDA
Medications
  • None
Current Findings
  • Persistent apical radiolucency; re-accessible canal
  • Adequate structure and periodontal support
  1. Question 1
    Moderate
    Given a restorable, re-accessible tooth, the preferred first option is:
  2. Question 2
    Moderate
    Through the Time lens, this decision is informed by:
  3. Question 3
    Moderate
    If retreatment were attempted and failed, the next option (with the canal not re-accessible) would be:
  4. Question 4
    Moderate
    Extraction would become the better choice if:
  5. Question 5
    Moderate
    Choosing among these options ultimately weighs:

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Patient case: A treated front tooth that's basically intact
0 of 5 answered, 0 correct
Patient
Female, 33 years old
Chief Complaint
Final restoration after a root canal on an upper front tooth.
Background and/or Patient History
  • Endodontically treated maxillary incisor
  • Intact walls with only a small lingual access cavity
  • Good esthetics; the patient asks whether she needs a crown
Allergies
NKDA
Medications
  • None
Current Findings
  • Minimal structural loss; intact, sound walls
  • Small access only
  1. Question 1
    Moderate
    For an intact anterior endo tooth with a small access, the conservative approach is:
  2. Question 2
    Moderate
    Through the Structure lens, the reason a crown may be avoided here is:
  3. Question 3
    Moderate
    Restoring conservatively rather than crowning this tooth reflects the principle of:
  4. Question 4
    Moderate
    Even for this conservatively restored tooth, long-term success still requires:
  5. Question 5
    Moderate
    If this anterior tooth were instead badly broken down and discolored, the plan might shift toward:

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Patient case: A canal left under a temporary too long
0 of 5 answered, 0 correct
Patient
Male, 44 years old
Chief Complaint
"My root canal tooth flared up; I never got the permanent filling."
Background and/or Patient History
  • Root canal completed months ago; only a temporary was ever placed
  • The temporary is broken down and the tooth is symptomatic again
  • The canal fill itself looks adequate radiographically
Allergies
NKDA
Medications
  • None
Current Findings
  • Radiographically adequate obturation but a broken-down, leaking temporary
  • New periapical inflammation
  1. Question 1
    Moderate
    Despite the adequate canal fill, the failure here is best explained by:
  2. Question 2
    Moderate
    Through the Time lens, what went wrong was:
  3. Question 3
    Moderate
    The lesson is that a definitive restoration should be placed:
  4. Question 4
    Moderate
    Because the canal was recontaminated, management now is generally:
  5. Question 5
    Easy
    This case shows that the endodontic and restorative results are:

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Patient case: Running all four lenses on one tooth
0 of 5 answered, 0 correct
Patient
Female, 61 years old
Chief Complaint
Deciding whether to save or replace a problematic molar.
Background and/or Patient History
  • Endodontically treated molar with a moderate amount of remaining structure and a usable ferrule
  • Heavy bruxism; an unhealed but small periapical lesion; canal re-accessible
  • Good periodontal support; patient prefers to keep the tooth if reasonable
Allergies
NKDA
Medications
  • None
Current Findings
  • Restorable structure with a ferrule; re-accessible canal; small persistent lesion
  • Parafunction (bruxism) present; sound periodontal support
  1. Question 1
    Moderate
    Through the Structure lens, this tooth is favorable because:
  2. Question 2
    Moderate
    Through the Force lens, the bruxism means the plan should include:
  3. Question 3
    Moderate
    Through the Time lens, the small persistent lesion with a re-accessible canal suggests:
  4. Question 4
    Hard
    Through the Stability lens, the overall plan to give this tooth a good ten-year outlook is:
  5. Question 5
    Moderate
    This synthesis case shows that the SDF lenses together:

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Keep studying
Restore, Retreat, or Extract core recall

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

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