A Cracked Molar With an Isolated 7 mm Pocket

Diagnosis: cracked tooth with pulpal involvement (the lingering cold response indicates irreversible pulpitis) and a probable subgingival extension of the fracture along the distobuccal root.

The key judgement is not the diagnosis but the restorability, and three findings argue against it:

• The crack crosses the distal marginal ridge - a crack that reaches a marginal ridge is more likely to run subgingivally.
• The isolated 7 mm pocket on the distobuccal aspect is the most important sign. A narrow, isolated pocket adjacent to a crack usually represents periodontal breakdown along the fracture line, not ordinary periodontitis, and it implies the fracture extends below the crest of bone.
• The widened PDL at the distobuccal root is consistent with the same process.

A crack that extends subgingivally cannot be sealed predictably. The long-term failure rate in that situation is high, and heroic treatment risks years of symptoms and repeated visits before inevitable extraction. Without raising a flap the extent cannot be confirmed, so the decision should be framed as a probability, not a certainty, and discussed with the patient.

1. Extraction and replacement (implant, bridge or denture)

• Predictable resolution of symptoms; removes the crack entirely.
• Requires assessment of bone volume, occlusal scheme and the adjacent teeth; implant placement should follow healing.
• This is the option with the most predictable long-term outcome given the subgingival pocket.

2. Root canal treatment plus cuspal coverage

• Appropriate only if the crack is supragingival and the tooth can be fully covered.
• Even then, survival of root-treated cracked molars is lower than for non-cracked molars, and the isolated pocket suggests a worse trajectory.
• If attempted, the patient must understand that extraction may still be needed, and a post-operative review with defined failure criteria should be built in.

3. Monitoring or no treatment

• The pain is progressive and will not resolve; this is a legitimate choice only if the patient understands the likely outcome and can return if symptoms escalate.

A useful framing: the crack, not the pulp, is the problem. Root canal treatment addresses the symptom but not the structural defect.

Say: 'I can try to save it, but I want you to know what I am worried about. The pocket on the back corner suggests the crack runs below the gum and possibly below the bone. If that is true, the tooth will probably fail even if we do everything right - and you may go through a root canal and a crown and still lose it. If we go ahead, I will treat it in stages so we find out early whether it is working.'

Do:

• Consider raising a small flap to visualise the crack extent before committing to root canal treatment. If the crack reaches below the crestal bone, recommend extraction.
• If proceeding, complete the root canal treatment, place a well-adapted cuspal-coverage restoration (full-coverage crown or onlay with adequate ferrule), and adjust the occlusion.
• Set explicit review points at 3 and 6 months with defined failure criteria: persistent pocket, symptoms, radiographic change or crack propagation. Agree in advance that these trigger extraction.
• Document the discussion, the alternatives offered and the patient's informed choice.
• Do not promise survival figures you cannot support, and do not let the patient's preference override a clear clinical finding.