Retreatment Decision Calculator
Retreatment vs extraction analysis from clinical findings.
About this calculator
This calculator produces a weighted favorability score (0-100) for nonsurgical endodontic retreatment versus extraction, combining five case factors clinicians commonly weigh together: periapical pathology (PAI score), symptom duration, quality of the existing root canal filling, restorability of the remaining tooth structure, and the tooth's strategic importance in the arch (for example, as a bridge abutment). Restorability carries the largest single weight in the score because a tooth that cannot be predictably restored after retreatment is a poor retreatment candidate regardless of how favorable the endodontic factors look — a fundamentally different consideration than the endodontic-only factors like PAI score or fill quality, which describe how likely retreatment itself is to succeed.
A score of 60 or higher favors retreatment, 30-59 suggests weighing alternatives such as apicoectomy, and below 30 leans toward extraction. This is a decision-support index built from commonly cited clinical weighting factors, not a validated diagnostic instrument or a substitute for direct clinical and radiographic examination — periodontal status, occlusal load, patient medical history, and the patient's own preference for retaining a natural tooth are not captured here and should be weighed alongside this score before finalizing a treatment plan.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
Inputs
Results
Retreatment score (0-100)
73
How to Use This Calculator
- Enter the PAI Score (1-5) from the periapical radiograph — higher scores indicate more significant pathology.
- Set Symptom Duration (months) and rate Existing Fill Quality (1 = good, 3 = poor).
- Rate Restorability (1 = ideal, 4 = questionable) and Tooth Strategic Importance (1-3).
- Review the Retreatment Score (0-100) and Recommendation (1 = extract, 2 = consider alternatives, 3 = retreat).
- Document the score in the patient record to support the treatment decision discussion.
How the result changes with Symptom duration (months)
| Symptom duration (months) | Retreatment score (0-100) |
|---|---|
| 3 | 73 |
| 4.5 | 73 |
| 9 | 68 |
| 15 | 63 |
What each input means
- PAI score
- Periapical index (Orstavik): 1 = normal, 5 = severe pathology.
- Symptom duration (months)
- Duration of symptoms in months.
- Existing fill quality
- Quality of the existing root canal filling on radiograph.
- Restorability
- Restorability of the remaining tooth structure after retreatment.
- Strategic importance
- Strategic value of the tooth in the overall dental arch/prosthetic plan.
What each result means
- Retreatment score (0-100)
- Higher = more favorable for retreatment.
- Recommendation (1-3)
- 1 = extract, 2 = consider alternatives, 3 = retreat.
- Extraction favorability (0-100)
- Higher = extraction more appropriate.
- Est. retreatment success (%)
- Estimated probability of retreatment success.
- Apicoectomy alternative (0-100)
- Score for apicoectomy as an alternative to retreatment.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersPAI score (1-5) = 3, Symptom duration (months) = 6, Existing fill quality (1-3) = 2, Restorability (1-4) = 2 = 5 input(s) provided
- Calculate Retreatment scoreRetreatment score73 = 73
- Calculate RecommendationRecommendation3 = 3
- Calculate Extraction favorabilityExtraction favorability27 = 27
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does restorability weigh more heavily than PAI score in the retreatment decision?
Restorability describes whether the tooth can predictably support a functional restoration after retreatment is completed, which is a precondition for the whole procedure being worthwhile. PAI score and the other endodontic factors describe how likely the retreatment itself is to resolve periapical disease, but a technically successful retreatment on an unrestorable tooth still fails clinically, so restorability carries the largest weight in this score.
What does a retreatment score between 30 and 59 mean?
A score in that middle range means the case has a mix of favorable and unfavorable factors and does not clearly point toward either retreatment or extraction. The calculator suggests weighing alternatives such as apicoectomy (surgical endodontic retreatment) rather than defaulting straight to nonsurgical retreatment or extraction.
How does symptom duration affect the retreatment recommendation?
Shorter symptom duration (6 months or less) contributes more favorably to the retreatment score than chronic symptoms lasting over a year, reflecting that long-standing chronic periapical disease can be somewhat less predictable to resolve with retreatment alone, though it is a smaller factor in the overall score than restorability or periapical pathology severity.
Is a high retreatment score a guarantee that retreatment will succeed?
No — the estimated success rate this calculator reports is drawn from typical literature ranges (roughly 60-85%) and adjusted for the input factors, but it is a population-level estimate, not a patient-specific prediction. Actual outcomes depend on canal anatomy, the presence of a missed canal or fracture, and factors this score does not capture.
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