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When a tooth outgrows a filling · Operative Dentistry · INBDE Patient Cases

Restoration Failure & the Decision INBDE Patient Cases

By Dr. Isaac Sun, DDS

8 ADA INBDE-format patient cases on restoration failure & the decision. 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 restoration failure and the restorative decision, framed by the Structural Decision Framework: a broken-down MOD amalgam with undermined cusps under bruxism needing cuspal coverage, diagnosing true secondary caries at a composite margin and choosing repair versus replacement, the postoperative sensitivity differential between a high occlusal contact and microleakage, an endodontically treated molar requiring cuspal coverage to prevent fracture, monitoring a sealed asymptomatic ditched margin rather than enlarging the cavity, cracked tooth syndrome treated with cuspal coverage and parafunction control, the restorative death spiral and the shift from a repeatedly enlarged direct filling to an indirect restoration, and conservative repair of a localized chip in an otherwise sound restoration. Topics include secondary caries, marginal breakdown, fracture, postoperative sensitivity, repair versus replacement, and the large-filling-versus-crown decision read through Structure, Force, Time, and Stability.

Case Coverage Map
What each case is testing
A huge old silver filling with a cracked-looking cusp:
Structure and Force lenses on a broken-down MOD amalgam under bruxism, cuspal coverage versus a larger filling, and the operative/prosthodontic scope line.
Decay creeping back under a white filling:
Diagnosing true secondary caries (Time lens), localized repair versus replacement, and managing the underlying caries risk that caused it.
Sorting out a sensitive new filling:
Postoperative sensitivity differential: high occlusal contact versus microleakage, conservative first steps, and the line into irreversible pulpitis.
A root-canaled molar with just a filling in it:
Why endodontically treated posterior teeth need cuspal coverage, the bite-stick crack sign, and the Stability lens on delaying coverage.
A worn margin that doesn't hurt:
Monitoring a sealed, asymptomatic ditched margin (Time lens), the death-spiral rationale against replacement, and what would change the decision.
Sharp pain only when she lets go of a bite:
Cracked tooth syndrome, cuspal coverage to splint segments, the Force lens on parafunction and occlusal guards, and the endodontic boundary.
A filling that's been redone three times:
The restorative death spiral, the Structure-lens shift from direct to indirect restoration, and breaking the cycle by controlling caries risk.
A small chip on an otherwise good filling:
Repair conserving structure, the criteria that make repair appropriate, composite-to-composite bonding, and the SDF reading that favors repair.
Patient case: A huge old silver filling with a cracked-looking cusp
0 of 5 answered, 0 correct
Patient
Male, 57 years old
Chief Complaint
"My old back filling feels like it might break."
Background and/or Patient History
  • A very large MOD amalgam placed decades ago on a lower molar
  • Both marginal ridges are gone and the remaining cusps look undermined
  • History of nighttime clenching (parafunction)
Allergies
NKDA
Medications
  • None
Current Findings
  • Wide isthmus, thin unsupported lingual cusp, no recurrent caries detected
  • Occlusal wear facets consistent with bruxism; tooth vital and asymptomatic
  1. Question 1
    Moderate
    Through the Structure lens, the key problem is that:
  2. Question 2
    Moderate
    Through the Force lens, the bruxism matters because it:
  3. Question 3
    Moderate
    The structurally sound restorative choice for this tooth is:
  4. Question 4
    Moderate
    Through the Stability lens, cuspal coverage is favored because it:
  5. Question 5
    Easy
    Whose scope is the actual fabrication and cementation of the crown if one is chosen?

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Patient case: Decay creeping back under a white filling
0 of 5 answered, 0 correct
Patient
Female, 41 years old
Chief Complaint
"There's a dark, catchy spot at the edge of an old filling."
Background and/or Patient History
  • A composite placed several years ago on a premolar
  • High caries risk: frequent snacking and reduced salivary flow
  • The gingival margin feels soft and catches an explorer
Allergies
NKDA
Medications
  • An antihistamine (dry mouth)
Current Findings
  • Soft, cavitated, catching gingival margin with a radiolucency on bitewing
  • Recurrent caries confirmed at the margin
  1. Question 1
    Moderate
    The soft, catching, radiolucent margin indicates:
  2. Question 2
    Moderate
    Through the Time lens, this margin is:
  3. Question 3
    Moderate
    Because the recurrent caries is localized to one margin of an otherwise sound restoration, a conservative option is to:
  4. Question 4
    Moderate
    Equally important to restoring the margin is addressing:
  5. Question 5
    Moderate
    If recurrent caries were instead found around every margin with the restoration breaking down, the decision would shift to:

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Patient case: Sorting out a sensitive new filling
0 of 5 answered, 0 correct
Patient
Female, 33 years old
Chief Complaint
"My filling from last week is still sensitive."
Background and/or Patient History
  • Composite placed one week ago on a molar
  • Reports a sharp twinge when biting on one spot and some cold sensitivity
  • No spontaneous or night pain
Allergies
NKDA
Medications
  • None
Current Findings
  • Tooth vital; brief, non-lingering responses
  • A premature contact is detected on the new restoration with articulating paper
  1. Question 1
    Moderate
    The first, simplest cause to check for biting sensitivity on a new restoration is:
  2. Question 2
    Moderate
    The appropriate first management given the detected premature contact is to:
  3. Question 3
    Hard
    If, after occlusal adjustment, only thermal sensitivity with a stainable, leaking margin remained, the likely cause would be:
  4. Question 4
    Moderate
    Distinguishing a high contact from microleakage matters because:
  5. Question 5
    Moderate
    Lingering, spontaneous pain developing later would instead suggest:

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Patient case: A root-canaled molar with just a filling in it
0 of 5 answered, 0 correct
Patient
Male, 49 years old
Chief Complaint
Review of a molar that had a root canal a year ago.
Background and/or Patient History
  • Lower first molar had root canal therapy and was restored with only a large composite
  • Both marginal ridges had been lost to access and prior caries
  • Now reports a vague cracking sensation when chewing hard foods
Allergies
NKDA
Medications
  • None
Current Findings
  • Endodontically treated molar with a large direct restoration and no cuspal coverage
  • No new caries; tooth tender to a bite-stick test on one cusp
  1. Question 1
    Moderate
    An endodontically treated posterior tooth is especially fracture-prone because:
  2. Question 2
    Moderate
    Reading this through the Structure and Force lenses, the indicated restoration is:
  3. Question 3
    Moderate
    The vague cracking sensation and positive bite-stick test suggest:
  4. Question 4
    Moderate
    Through the Stability lens, delaying cuspal coverage on this tooth risks:
  5. Question 5
    Easy
    Selecting and timing the coverage is an operative-restorative decision, while the crown's fabrication is:

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Patient case: A worn margin that doesn't hurt
0 of 5 answered, 0 correct
Patient
Male, 64 years old
Chief Complaint
Routine recall; an old amalgam looks worn at the edge.
Background and/or Patient History
  • A 20-year-old amalgam on a molar shows minor marginal ditching
  • Asymptomatic; the patient is low caries risk with good hygiene
  • No catch, softening, or radiographic change at the margin
Allergies
NKDA
Medications
  • None
Current Findings
  • Minor marginal ditching, margin hard and sealed, no recurrent caries
  • Tooth asymptomatic and functional
  1. Question 1
    Moderate
    Minor marginal ditching with a hard, sealed, caries-free margin is best managed by:
  2. Question 2
    Moderate
    Through the Time lens, this restoration is:
  3. Question 3
    Moderate
    The principle that argues against routinely replacing this restoration is:
  4. Question 4
    Moderate
    The patient's low caries risk and good hygiene affect the decision by:
  5. Question 5
    Moderate
    Monitoring would change to intervention if, at a future recall, the margin became:

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Patient case: Sharp pain only when she lets go of a bite
0 of 5 answered, 0 correct
Patient
Female, 46 years old
Chief Complaint
"A sharp jolt when I bite on something hard and then release."
Background and/or Patient History
  • An intact but heavily restored molar with a large old composite
  • Sharp pain specifically on release of biting pressure; occasional cold sensitivity
  • No spontaneous pain; clenches under stress
Allergies
NKDA
Medications
  • None
Current Findings
  • Pain reproduced on release with a bite stick on a specific cusp
  • Vital pulp; a hairline crack is suspected
  1. Question 1
    Hard
    Sharp pain on release of biting pressure is the classic sign of:
  2. Question 2
    Moderate
    Through the Force and Stability lenses, the structurally sound treatment is:
  3. Question 3
    Moderate
    The patient's clenching is relevant because, through the Force lens, it:
  4. Question 4
    Moderate
    A reasonable additional measure for this clenching patient is:
  5. Question 5
    Moderate
    If the crack were later found to extend into the pulp or the tooth became irreversibly symptomatic, care would shift toward:

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Patient case: A filling that's been redone three times
0 of 5 answered, 0 correct
Patient
Female, 52 years old
Chief Complaint
"This same tooth keeps needing the filling redone."
Background and/or Patient History
  • A molar restoration replaced three times over the years, each time larger
  • Now a very wide, deep direct restoration with thin surrounding walls
  • Recurrent caries has again been found at a margin
Allergies
NKDA
Medications
  • None
Current Findings
  • Each replacement has enlarged the preparation; walls now thin and undermined
  • Little sound structure remains to support another direct restoration
  1. Question 1
    Moderate
    The pattern of an ever-enlarging preparation with each replacement illustrates:
  2. Question 2
    Moderate
    Through the Structure lens, repeating another large direct restoration would:
  3. Question 3
    Moderate
    Given the thin walls and minimal remaining structure, the decision should shift to:
  4. Question 4
    Moderate
    Recognizing when to switch from direct to indirect restoration is fundamentally a judgment about:
  5. Question 5
    Moderate
    Breaking the cycle for the long term also requires:

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Patient case: A small chip on an otherwise good filling
0 of 5 answered, 0 correct
Patient
Male, 38 years old
Chief Complaint
"A little piece chipped off the edge of a filling."
Background and/or Patient History
  • A large composite placed two years ago, otherwise sound and well-sealed
  • A small marginal chip at one corner with no recurrent caries
  • Patient is low caries risk
Allergies
NKDA
Medications
  • None
Current Findings
  • Localized marginal chip; the remainder of the restoration is intact and sealed
  • No softening, catch, or radiolucency elsewhere
  1. Question 1
    Moderate
    For a small, localized chip in an otherwise sound, sealed restoration, the conservative choice is:
  2. Question 2
    Moderate
    The main advantage of repair over replacement here is that it:
  3. Question 3
    Moderate
    Before repairing, the clinician must confirm that:
  4. Question 4
    Moderate
    To bond new composite to the existing composite during repair, the surface is typically:
  5. Question 5
    Moderate
    Through the SDF lenses, this case is a repair because:

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Restoration Failure & the Decision core recall

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

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