Retreatment Decision With a Separated File and a Cast Post Before Bridgework
Maryam, 52, is referred to a specialist endodontic practice in Salmiya for retreatment of 16 before her dentist makes a new three-unit bridge. The tooth had root canal treatment 12 years ago and has a cast post-and-core in the palatal canal and a metal-ceramic crown. She is asymptomatic. The referral radiograph shows a separated rotary file in the mesiobuccal canal about 5 mm from the apex, a 4 mm periapical radiolucency, and obturation 2 mm short of the apex. A small-field CBCT confirms the file fragment is in the apical third and has not perforated the root; the MB canal is blocked by the fragment, and the post is 10 mm long with 4 mm of gutta-percha below it. Medical history: hypertension controlled with amlodipine; no allergies. She is worried about 'surgery' and asks whether the tooth can simply be left alone because it does not hurt.
1. What are the reasonable treatment options for 16, and which would you recommend?
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The options are: (1) no treatment and radiographic monitoring; (2) nonsurgical retreatment, including post removal and attempted file retrieval or bypass; (3) surgical retreatment with root-end resection and retrograde filling, which may also remove or bypass the file fragment; (4) extraction with a fixed bridge or implant. The tooth is asymptomatic but has a 4 mm periapical lesion and a blocked canal, so 'no treatment' is not the same as 'no disease'.
I would recommend a CBCT-guided attempt at nonsurgical retreatment first, provided the tooth is restorable and the crown margin is acceptable. The file is 5 mm from the apex and not perforating, which gives a reasonable chance of retrieval or bypass. The post is in the palatal canal, separate from the MB file, so post removal is a distinct step rather than an impossible combination. The patient wants to keep the tooth and is about to invest in a bridge, so the lesion should be addressed before that investment.
The recommendation is conditional: if the post removal would leave insufficient tooth structure, or if the file cannot be retrieved or bypassed without perforation, I would stop and discuss surgery or extraction. I would not promise success.
2. How would you manage the cast post and the separated file, and what would make you stop and refer?
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I would access through the existing crown if the access can be sealed and the crown is retained; otherwise I would remove the crown and make a provisional. The cast post is removed with ultrasonic vibration around the post, careful excavation of the core, and a post puller if needed, preserving as much dentine as possible. I would take a radiograph after removal to confirm no root fracture.
For the file, I would work under magnification, create a staging platform, and attempt to expose the coronal 1–2 mm of the fragment with ultrasonic tips. I would try to bypass it with a small hand file before attempting retrieval; bypassing is often safer than pulling. If retrieval is attempted, it should be with an ultrasonically activated file or a dedicated extractor, never with uncontrolled force.
I would stop and refer if: the file cannot be visualized, the root is perforated, a fracture line appears, the post removal threatens the root, or the patient develops symptoms. Surgery is a reasonable referral option if nonsurgical access fails. The key is to avoid converting a restorable tooth into an unrestorable one in a single appointment.
3. She asks why she cannot simply leave the tooth alone because it does not hurt. How do you explain the decision and document it?
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I would explain that pain is a poor guide to infection. The 4 mm radiolucency means there is chronic apical periodontitis, and the blocked MB canal with a separated file is a reservoir that the body is not clearing. Asymptomatic does not mean stable; it can flare up, and it can compromise the bone site before bridgework.
I would also be honest about uncertainty. Observation with radiographic review is a legitimate option if she understands the trade-offs, but it does not remove the lesion and it may make later treatment harder. If she chooses observation, I would document that she was informed of the risks, including flare-up, bone loss, and possible loss of the tooth, and I would set a review interval.
Consent for retreatment should include the possibility of post removal, file retrieval or bypass, perforation, root fracture, need for surgery, and extraction. I would record the alternatives discussed, her questions, and her decision. If she proceeds, the bridge should not be made until the endodontic outcome is assessed.