Signs of root canal failure include recurring pain or tenderness around the treated tooth, swelling in the gum tissue near the root tip, a draining sinus tract (a pimple-like bump on the gum), or a growing radiolucency (dark area) visible on X-ray. Some failed root canals are asymptomatic and discovered incidentally on routine dental radiographs.

The most common causes are a missed canal that was never treated, incomplete disinfection of the canal system, a filling that did not seal to the root apex, coronal leakage from a defective restoration or delayed crown placement, and new decay that exposed the root canal filling to oral bacteria. Procedural complications like separated instruments or root perforations are less common causes.

No. Retreatment is performed under the same local anesthesia as an initial root canal, and IV sedation is available if desired. The procedure may take longer because the old filling material must be removed before re-treatment can begin, but discomfort levels during and after the procedure are comparable to an initial root canal.

Retreatment typically takes 90 minutes to two hours per visit, and complex cases may require two visits. The additional time is needed to remove all previous obturation material, locate and treat missed canals, and achieve thorough disinfection before re-sealing the canal system.

Specialist-performed retreatment achieves success rates of 77 to 89 percent in published studies — lower than initial treatment because the tooth already has a compromised history, but still high enough to be the preferred option over extraction when the tooth is restorable. Cases with identifiable and correctable causes of failure (like a missed canal) tend to have the best retreatment outcomes.

Not every tooth is a retreatment candidate. Teeth with vertical root fractures, severe post-endodontic root resorption, or insufficient remaining tooth structure for a crown may not be salvageable. Dr. Ostovar evaluates each case with CBCT imaging and clinical examination to determine whether retreatment, apicoectomy, or extraction is the most appropriate option.

The old gutta-percha and sealer are softened with heat and solvent (chloroform or a citrus-based solvent), then removed in stages using retreatment rotary files, Hedstrom hand files, and ultrasonic instruments. Complete removal is verified under the microscope and with radiographs. Residual filling material can harbor bacteria, so thorough removal is essential.

Yes, in most cases. The existing crown must usually be removed to access the canal system. Even if the crown could be preserved during treatment, the underlying seal has been compromised and a new crown provides the best long-term protection against coronal leakage, which is a leading cause of initial failure.

It depends on the cause of failure. If the failure is due to a missed canal, inadequate obturation, or coronal leakage, retreatment is preferred because it addresses the root cause. If the failure is due to a persistent periapical lesion despite adequate canal treatment, or if a post cannot be safely removed, apicoectomy may be the better option. Dr. Ostovar will recommend the approach with the highest likelihood of success for your specific case.

Yes, though post removal adds complexity and time. Dr. Ostovar uses ultrasonic vibration to loosen the cement bond around the post, then carefully extracts it without damaging the root. In cases where the post cannot be safely removed due to fracture risk, apicoectomy may be recommended instead.

CBCT imaging reveals the cause of failure in three dimensions — missed canals, short fills, periapical pathology, separated instruments, root perforations, and root fractures are all visible. This allows Dr. Ostovar to plan the retreatment strategy before beginning, significantly improving the likelihood of a successful outcome.

Bone healing around the root apex after retreatment can take 6 to 24 months to show radiographic improvement. Clinical symptoms (pain and swelling) typically resolve within one to two weeks. We schedule follow-up appointments at 6 and 12 months to monitor healing with periapical radiographs.

Yes. A significant portion of our retreatment cases are referrals from general dentists and other specialists in Beaverton, Hillsboro, Portland, and throughout Washington County. We provide detailed reports and imaging to referring dentists and coordinate the restorative treatment plan.

Most dental insurance plans cover retreatment under endodontic benefits, though some plans have a waiting period (typically five years) before retreatment on the same tooth is covered. We verify your specific benefits before treatment and provide a cost estimate. Financing options are available for out-of-pocket expenses.

If retreatment does not achieve healing, the next option is typically an apicoectomy (root-end surgery) to remove the infected root tip and seal it from the outside. If apicoectomy is not feasible or has already been attempted, extraction with replacement by a dental implant is the final option. Dr. Ostovar will discuss all options and their prognosis with you.