Why Root Canals Fail — and What Happens Next

Root canals are a core dental procedure for saving teeth. Successful root canals can restore and preserve a damaged tooth for decades. Yet, like any medical treatment, root canals aren’t always successful. One study found that root canal treatments have a failure rate of up to 18%. 

At Greenwich Dentistry in Greenwich, Connecticut, our dental team understands that no medical procedure is 100% perfect. But we also know that today’s advanced techniques and our experience offer an excellent chance of success with any procedure, including root canals. 

What’s a root canal 

Root canals treat inflammation or infection inside a tooth. The soft tissue of a tooth contains nerves and blood vessels; a root canal removes damaged tissue. Afterward, we clean and disinfect the inside of the tooth, sealing it with a filling or a crown. 

The goal is to eliminate infection and prevent reinfection. 

Why do root canals fail? 

Below are a few factors that can affect the success of your root canal. 

Hidden or missed canals 

Your teeth contain complex root structures, and it’s possible to miss a tiny canal during treatment. Any infected tissue left behind can cause reinfection. 

Incomplete cleaning or sealing 

The treated tooth must be thoroughly cleaned and tightly sealed to prevent bacteria from entering. If bacteria are missed or manage to return, you might need another treatment. 

New decay or damage 

A completed root canal doesn’t mean you’re home-free. You can still experience new decay, a cracked crown, or trauma to the tooth. 

Delayed restoration 

Dentists try to complete the restoration quickly. That means performing the root canal and scheduling crown placement as soon as the crown is ready. The crown protects the treated tooth, so getting that done without delay lessens the chance of reinfection.

Signs of root canal failure 

Symptoms of root canal failure might appear right away, or take months or years. Common ones include: 

• Constant pain or pressure 
• Sensitivity to heat or cold 
• Swelling or tenderness in the gums 
• A bump on the gum (abscess) 

If you experience these symptoms, don’t wait. The sooner we evaluate your tooth, the better chance we have of saving it. 

What’s next if your root canal fails? 

There are three main options to address a failed root canal: 

Retreatment 

We can remove the original filling materials, disinfect the canals again, and reseal the tooth. We can use imaging tools to assess the area. 

Apicoectomy (surgical root procedure) 

If root canal retreatment isn’t possible or hasn’t worked, you may be a good candidate for a minor surgical procedure. In an apicoectomy, the dentist accesses the root tip through the gum, removes the infected tissue, and seals the root’s end. 

Tooth extraction

If your tooth can’t be saved, extraction may be the only option. We can fill the gap with a dental implant, bridge, or partial denture. Modern implants are durable and natural-looking, with high success rates. 

If you have tooth pain, call the Cos Cob office of Greenwich Dentistry today. We can walk you through your options and recommend the best treatment. The sooner we see you, the better the outcome.