Painless periapical lesion and a separated file in a crowned mandibular molar
A 42-year-old man is referred to a district hospital dental unit with a six-year-old porcelain-fused-to-metal crown on the mandibular right first molar. He has no pain, no swelling and no sinus tract, but a routine radiograph taken for a job medical shows a 5 mm periapical radiolucency on the mesial root. A separated stainless-steel file, size 25, lies in the apical third of the mesiobuccal canal. The crown margins are clinically acceptable, probing depths are within 3 mm, and the tooth is in occlusal function with the adjacent second molar and second premolar. The patient travels four hours by bus and can attend only two appointments in the next three months. He has controlled hypertension treated with amlodipine. He asks whether the tooth can simply be left alone because it does not hurt, and whether the broken instrument means the tooth must come out.
1. The patient asks why a painless tooth needs any treatment at all. How do you choose between monitoring, nonsurgical retreatment, apical surgery and extraction, and which factors carry most weight in this case?
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The absence of symptoms is not the absence of disease. A 5 mm radiolucency with a previously root-filled canal represents asymptomatic apical periodontitis, an active infection with bone resorption, and it can progress to acute exacerbation or to loss of the tooth if left untreated. Monitoring is defensible only for a small, clearly healing lesion in a patient with no restorability or strategic value concerns; none of that applies here.
The decision rests on four weights, in this order:
- Strategic and restorative value. The tooth is a first molar in occlusal function. Loss would require an implant or a cantilever bridge involving the premolar. The crown is serviceable, so retaining the tooth is clearly preferable.
- Periodontal and structural integrity. Probing depths under 3 mm and an acceptable margin mean no furcation or crown-removal complication to force extraction.
- The root filling and the obstruction. The old filling is inadequate; the separated file is a technical obstacle, not in itself an indication for extraction. Many such canals can be negotiated or cleaned to the level of the fragment.
- Patient access and preference. Two visits in three months is enough for access, chemomechanical preparation and obturation, but not for a long multi-stage surgical plan without planning.
So I would explain that the tooth needs retreatment, plan a two-visit nonsurgical approach, and reserve surgery or extraction as contingency rather than first choice.
2. At the first visit the file cannot be bypassed and the apical third stays obstructed. Set out the realistic options, with the biological and practical argument for each.
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Three options exist, and each is judged against how much infected apical tissue can be removed and how the tooth will be restored.
- Complete the retreatment to the level of obstruction. Ultrasonic activation, adequate irrigation and a good coronal seal debulk the canal, but the apical 2 to 3 mm remain untouched. Healing rates fall compared with a fully negotiated canal, so this works best when the lesion is small and the patient accepts 12-month radiographic review. Practically it fits the two-visit limit and preserves the crown.
- Apical surgery. Root-end resection removes the contaminated apical 3 mm and the fragment with it, and retropreparation with a bioceramic filling seals the canal. Success is high for a lesion confined to the apical region with an intact coronal restoration, but it risks crown fracture, root shortening and adjacent structure damage, and it needs a surgeon and a further visit.
- Extraction and replacement. This removes the problem definitively but sacrifices a functioning molar and transfers cost and surgical risk to an implant or bridge.
Given a healthy patient, a strategic tooth and a lesion limited to the apex, I would attempt option 1 first and review at 12 months with a periapical film, moving to option 2 if the lesion persists or enlarges. Extractions should not be the default answer to a separated instrument.
3. What would you tell the patient about prognosis and the two-visit constraint, and what would make you change course mid-treatment?
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Consent must be honest about uncertainty. I would say that retreatment of a molar with an obstructed canal has a reasonable but reduced chance of complete healing, that the tooth will be reviewed radiographically at 6 and 12 months, and that a decision about surgery or extraction may be needed then. I would explain that the fragment does not itself mean the tooth is doomed. The two-visit plan is workable: visit one for access, removal of the old filling, negotiation and irrigation; visit two for obturation and core, provided the tooth is asymptomatic and the canal is dry.
I would change course if:
- the canal cannot be negotiated and the patient develops pain, swelling or a sinus tract before the second visit;
- the crown fractures or a root fracture is identified under magnification or on a cone-beam image;
- profound anaesthesia cannot be achieved, which makes an unpleasant two-visit plan unacceptable;
- the patient cannot return within a reasonable interval and the tooth has an acute component;
- medical review finds a new contraindication such as uncontrolled diabetes or anticoagulation that needs coordination.
I would also document that the alternative of extraction with implant or bridge replacement was discussed, and that the patient agreed to attempt retention. Explaining contingency in advance prevents the second visit from becoming a confrontation about a plan that has already changed.