When a previously treated tooth becomes symptomatic or shows a lesion at the root tip, there are three paths forward: retreatment, apicoectomy, or extraction. The first two both save the tooth. Patients often arrive having heard one term or the other from a friend or a search result, and assume it is a matter of preference. It is not. The choice is driven by what is causing the failure and what is standing in the way of fixing it.
Here is the short version, and then the reasoning behind it. Nonsurgical retreatment is the default. We choose apicoectomy when we cannot safely or usefully get back down the canal, or when retreatment has already been tried and the problem persists.
The Two Procedures
Inside the Tooth, or Outside It
Retreatment
Nonsurgical. We reopen the tooth through the biting surface, remove the old root filling material, clean and disinfect the entire canal system including anything missed the first time, and reseal it.
One or two visits, local anesthetic, no incision. Recovery is typically mild soreness for a few days.
Apicoectomy
Surgical. We access the root tip through the gum, remove the infected tissue and the last few millimeters of root, and place a biocompatible seal at the cut end from the outside.
One visit of roughly an hour, local anesthetic, a few sutures. Recovery involves mild swelling for two to three days.
Why Retreatment Is the Default
The overwhelming majority of root canal failures are caused by bacteria remaining somewhere in the canal system — most often in a canal that was never located. If the source of the infection is inside the tooth, the most direct and most complete way to eliminate it is to go back inside the tooth.
Retreatment addresses the entire canal, not just the terminal few millimeters. Under the operating microscope at up to 25× magnification, a missed MB2 canal in an upper molar or a second canal in a lower incisor becomes visible in a way it simply is not with the naked eye. Once located, negotiated, disinfected, and sealed, the reason the tooth failed is gone. Nothing is surgically removed, and the tooth keeps its full root length and its full attachment to bone.
There is also a sequencing argument. Retreatment does not preclude surgery later; if it does not resolve the lesion, apicoectomy remains available. The reverse is less true, because surgery shortens the root and complicates a later nonsurgical approach. When both are reasonable, we do the one that preserves the most options.
When Apicoectomy Is the Right Call
Surgery becomes the better option when the path back down the canal is blocked, destructive, or already exhausted. Several scenarios point that direction.
A post and crown that would be destroyed on removal. If a well-fitting post is cemented deep in the root, removing it risks fracturing the root and often means replacing an expensive restoration. When the rest of the canal work looks sound and the problem is confined to the apex, going in from the side is both safer and less costly.
An obstruction in the canal. A separated instrument, a hard cement blockage, or a severely calcified canal can make full-length access impossible without unacceptable risk to the root.
Retreatment has already been done. If the canals have been thoroughly re-cleaned and the lesion persists, the remaining bacteria are usually in the apical anatomy or in the surrounding tissue, where surgery reaches them directly.
A lesion that needs to be biopsied or a defect that needs repair. Some periapical lesions warrant tissue diagnosis, and some perforations or resorptive defects can only be repaired from the outside. Endodontic microsurgery handles all of it in a single visit.
Success Rates: Closer Than You Think
Patients often assume surgery is the desperate last resort with poor odds. That reputation comes from an older generation of technique. Apicoectomy performed without magnification, using amalgam as a root-end filling and a bur to cut the preparation, produced mediocre results. Contemporary microsurgery is a different procedure: the microscope allows the cut root surface to be inspected directly for missed anatomy and cracks, ultrasonic tips prepare the root end along the canal’s true axis, and modern bioceramic sealing materials bond well and are highly biocompatible.
Reported success rates for modern endodontic microsurgery are substantially higher than for the traditional technique and fall into a range comparable with retreatment. In practice, this means the decision can be made on clinical logic rather than on a large gap in expected outcome.
25×
Magnification used in both procedures
1–2
Visits for most retreatment cases
~1 hr
Typical apicoectomy appointment
The Decision Starts With a 3D Scan
Neither procedure should be planned from a two-dimensional radiograph alone. A CBCT scan shows us whether there is an untreated canal (which favors retreatment), how close the root tip sits to the sinus floor or the inferior alveolar nerve (which shapes surgical planning), the true three-dimensional size of the lesion, and whether there is a root fracture that would make either procedure futile.
Only after that do we discuss the plan with you, including what we expect to find, what we will do if we find something different, and what the realistic prognosis is. Our endodontists work through these complex cases with a straightforward philosophy: if the tooth can be saved, we explain how, and if it cannot, we tell you directly. You can read more about the broader picture in can a failed root canal be saved.
Find Out Which Procedure Your Tooth Needs
A consultation with CBCT imaging answers the question in one visit. Both San Francisco locations offer retreatment and endodontic microsurgery.