Who this is for
- A tooth that had a root canal hurts when you bite, has swollen, or has a pimple on the gum.
- An X-ray shows a dark area at the root tip of a treated tooth that has not healed, or is new.
- A crown is being replaced on a treated tooth whose old root filling looks poor on the X-ray.
- You have been told an old root canal has failed and want to know the choices before an extraction.
Why a treated tooth can need it
- A narrow, curved or extra canal was not found or not fully cleaned the first time.
- The crown or filling on top came late, or leaked, and saliva and bacteria got back inside.
- New decay, or a loose or broken crown or filling, exposed the root filling.
- The tooth cracked. A crack that runs down the root usually means the tooth cannot be kept.
What we do at our office
Dr. Baruch Tetri, DDS, diagnoses the tooth: how it responds when tapped and to biting, how the gum around it probes, and what the X-rays show at the root tip. A limited 3D scan (CBCT) is used when a flat X-ray cannot answer the question, which is often the case in a tooth that was treated before. Either way the diagnosis, the restoration afterward and the follow-up stay with us.
Retreatment is done under an operating microscope, with the tooth isolated by a thin rubber sheet (a dental dam).
The choices
- Retreatment. The old filling material is removed through the top of the tooth, the canals are cleaned and disinfected again, looking for any canal that was missed, and then refilled and sealed.
- Surgery at the root tip. When the canals cannot be reached from the top, for example behind a post you want to keep or a blocked canal, the root tip is cleaned and sealed through the gum instead. See surgery at the root tip.
- Extraction. When the tooth is cracked through the root or too little of it is left, it is removed, and the gap can be left, bridged or filled with an implant. See tooth extraction.
What happens at the visit
- Numbing and isolation. The tooth is numbed, and a dental dam keeps saliva out and the cleaning solutions in. Sedation is available after a medical review, where our permits and team allow.
- Getting inside. We reach the canals through the crown or filling. Sometimes a crown or a post has to come off first; we tell you beforehand if that is likely.
- Removing the old filling. The old root filling is taken out, and the canals are searched for anything missed: an extra canal, a gap, a broken piece of an earlier instrument.
- Cleaning and refilling. The canals are cleaned, disinfected and filled again, and the top of the tooth is sealed.
- The restoration. A good, tight crown or filling on top matters as much as the treatment inside, so it follows soon after.
We check healing with an X-ray at follow-up.
What the research shows
- About three in four retreated teeth heal completely, in a review of the studies of retreatment.
- Healing was more likely when the tooth had no infection at the root tip before treatment, when the canals were filled to the right length, and when the crown or filling on top was sound.
- Surgery at the root tip healed somewhat more often in the first two to four years (about 78 against 71 in 100), while retreatment did better over longer follow-up; a Cochrane review found too few good trials to name one clearly better.
Risks and limits
- Not every tooth heals: in roughly one in four, the infection persists, and surgery or extraction follows.
- Removing a crown or a post can damage it, or the tooth under it, and a new crown may be needed.
- A crack found during retreatment usually ends the attempt to save the tooth.
- Blocked canals or a broken instrument cannot always be bypassed; then surgery at the root tip is the route.
- Soreness for a few days is normal. Swelling that spreads, or a fever, means call us the same day; trouble swallowing or breathing is an emergency: call 911.
Questions patients ask
Why did my root canal fail?
Most often bacteria stayed in, or got back in: a canal that was missed, a filling that leaked, a crown that came too late or broke. Sometimes the tooth cracked. The examination and the X-rays usually show which.
Is it better to retreat the tooth or to get an implant?
It depends on the tooth. A tooth with sound walls and no crack is usually worth retreating, since it keeps your own root and the bone around it. A cracked tooth, or one with little left, is often better replaced. We show you what we see before you decide.
Does retreatment hurt?
With the tooth fully numb, the treatment itself should not; it takes longer than the first root canal. Soreness afterward usually responds to over-the-counter pain relief.
What if I leave it?
An infection at the root tip does not clear on its own; it tends to grow and can end in an abscess and the loss of the tooth.
Sources
- American Association of Endodontists: Endodontic retreatment
- Ng, Mann, Gulabivala: Outcome of secondary root canal treatment, a systematic review (2008)
- Torabinejad et al.: Outcomes of nonsurgical retreatment and endodontic surgery, a systematic review (2009)
- Cochrane review: Surgical versus non-surgical endodontic re-treatment (2007)
Request a visit
Bring or send your X-rays and we will tell you whether the tooth can be kept; we are at 16690 Collins Avenue, Suite 701, Sunny Isles Beach, serving Aventura and greater Miami.