KYT Dental Services
SDF · Applied Scenario

Recurrent decay under a crown: redo or extract?Decay is already present. Now the decision gets real.

Recurrent decay under a crown means bacteria have already found a pathway under the margin. At that point, the question is no longer “is the crown aging.” The question is whether the remaining tooth structure can be preserved with a redo, or whether the decay has already consumed enough reserve that extraction is the stable endpoint.

Back to aging patterns

Quick answer

If recurrent decay is shallow and margins are accessible, a crown redo can be predictable. If decay is deep, extends subgingivally, or the patient’s maintenance history is unreliable, the risk shifts fast. In SDF, the decision is about preserving structural reserve before the ladder escalates to root canal or extraction.

Earlier stage

Many recurrent decay cases begin as interface instability before decay is visible.

Marginal leakage: replace now or monitor?
Redo crown that stays predictable vs decay that forces extraction

The difference is how much structural reserve is left, how deep the decay extends, and whether margins are accessible for long-term stability.

Stable
When a crown redo is predictable
Decay is limited, margins are accessible, and maintenance is realistic.
  • Margins stay clean and accessible
    Hygiene and recall keep inflammation low.
  • Contacts stay stable
    No new high spots or force migration patterns.
  • Supporting tooth remains sound
    No new cracks undermining the foundation.
  • Bite forces are managed
    Grinding is buffered instead of testing the interface nightly.
Failure site
When extraction becomes the stable endpoint
Decay extends deep or subgingival, and reserve is already consumed.
  • Decay extends subgingival
    Margins become hard to clean and hard to restore predictably.
  • Structural reserve is depleted
    The tooth cannot support another predictable rebuild.
  • Crown margin location hides progression
    Deep margins allow decay to advance before it is obvious.
  • Compliance history is unreliable
    Late discovery makes escalation more likely than preservation.
5–10 year outlook after recurrent decay is found

Once decay is under a crown, outcomes depend on depth, margin access, and compliance reality.

Think in forces + foundation + follow-through.
Predictable redo
Lower risk
Redo crown stays stable when decay was caught early and margins are maintainable.
  • Healthy gums at margins
  • Stable contacts
  • No repeat sensitivity
Escalation pressure
Moderate risk
Deeper decay and subgingival extension increase risk of root canal or structural loss.
  • Early margin leakage
  • Localized inflammation
  • Small contact changes
Extraction endpoint
Higher risk
Reserve is depleted and predictability shifts toward extraction and replacement planning.
  • Deep or subgingival decay
  • Structural reserve loss
  • High escalation risk if delayed
What to do when decay is under a crown

The goal is not urgency. The goal is preserving options before reserve is consumed.

Monitor intelligently and protect force
Often the goal
Track margins and contacts and control overload so the interface stays stable.
Best for
  • Crowns with stable margins
  • No symptoms
  • People committed to maintenance
Tradeoffs
  • Requires consistent recalls
  • Needs bite monitoring over time
Watch for
  • Ignoring new bite changes or gum inflammation at the edge
Replace when early instability appears
Situational
Re-do becomes safer when problems are early, not after deep decay or fracture.
Best for
  • Early margin leakage
  • Recurrent decay risk
  • Food packing or bite changes
Tradeoffs
  • Irreversible step
  • The tooth may have less reserve than the first time
Watch for
  • Waiting until it becomes a root canal or fracture event
Extract and plan replacement
Not always right
When reserve is depleted, extraction can be the stable endpoint that prevents repeated escalation.
Best for
  • Deep subgingival decay
  • Low remaining structure
  • History of late detection
Tradeoffs
  • Irreversible step
  • Requires replacement planning
Watch for
  • Trying to save a tooth that keeps consuming reserve
How SDF evaluates recurrent decay under a crown

Once decay exists under a crown, the key variables are depth, margin access, force, and compliance reality.

Structure
What is the remaining tooth foundation under the crown?
Force
Is load stable, or drifting into overload at the crown?
Timing
Is this early decay you can correct. or late-stage escalation where options narrow?
Long-term stability
If this repeats for 5–10 years, what fails first. margin, tooth, or force environment?
Related scenarios

Stay inside the same decision space. Compare one nearby scenario and one adjacent hub.

Back to Aging patternsRelated service: Replacing old dental work
Marginal leakage: replace now or monitor?
Failure patterns
Why old crowns fail after 15 years
Aging patterns
Large filling vs crown
Restoration thresholds
Structural collapse patterns
Restoration thresholds
If this matches your situation

The next step is simple. We examine structure, force, and timing in person. You do not need to decide everything today.

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