A 9-year-old kid falls off his bike and knocks his front tooth. The nerve dies. Normally, that tooth would need a root canal. But there’s a problem — the root isn’t fully formed yet.
See, when you’re a kid, your permanent teeth are still growing. The roots are short. The walls are thin. And the very tip of the root — where it should eventually close off — is wide open. Dentists call that an “open apex.”
Now imagine trying to do a traditional root canal on that tooth. You’d be working inside something that feels more like a thin-walled paper cone than a solid tooth. And you’d have no way to plug the bottom because there’s no bottom yet. The whole thing could fracture. It’s a real problem.
For a long time, the only option was a procedure called apexification — basically packing the open end with a special material to create an artificial barrier. It worked, sort of. The tooth survived, but it never got any stronger. The root stayed thin. The walls stayed fragile. That kid would spend the rest of his life with a tooth that could crack at any moment.
That’s where regenerative endodontics changes everything.
Wait — You Can Actually Regrow Tooth Tissue?
Yeah. That’s the part that blows people’s minds.
Regenerative endodontics is a procedure where we use the body’s own stem cells and growth factors to rebuild living tissue inside a damaged tooth. The root walls thicken. The root grows longer. The open apex closes on its own. The tooth literally gets stronger over time instead of just… surviving.
It’s not science fiction. It’s happening right now. And it’s one of the most exciting things in dentistry.
I’ve done these procedures at our Torrance office, and watching the follow-up X-rays over 6, 12, 18 months — seeing that root fill in and mature — honestly, it never gets old. The tooth is healing itself. We just set up the conditions for it to happen.
Who Is This For?
Regenerative endodontics works best for kids and teens whose permanent teeth haven’t finished developing. We’re talking about patients roughly between ages 7 and 18, though the sweet spot is usually 8 to 14.
The ideal candidate has:
- A permanent tooth with an open apex (the root tip hasn’t closed yet)
- A dead or dying nerve, usually from trauma or a deep cavity
- Enough healthy tooth structure to work with
The most common scenario? Exactly what I described at the top. A kid takes a hit to the mouth — bike fall, skateboard accident, basketball elbow, you name it. The tooth looks fine on the outside but the nerve inside has been damaged beyond repair. In the South Bay, with all the active kids playing sports year-round, I see this pretty regularly.
Good to know: Regenerative endodontics is specifically designed for immature teeth — permanent teeth whose roots are still developing. For fully mature adult teeth, traditional root canal treatment is still the gold standard.
How the Procedure Works
The procedure itself is surprisingly straightforward. It usually takes two visits.
Visit One: Clean Out the Infection
First, I numb the area and access the inside of the tooth, similar to how a root canal starts. But instead of removing all the tissue and filling the canals, I’m doing something different.
I irrigate the canals with disinfecting solutions to kill bacteria. Then I place a medicated paste (usually a mix of antibiotics) inside the tooth to continue fighting the infection over the next couple weeks. The tooth gets sealed up with a temporary filling, and the patient goes home.
That’s it for visit one. The medication sits in there and does its job.
Visit Two: Create the Scaffold
This is the cool part. A couple weeks later, the patient comes back. I remove the temporary filling and the medication. The canals should be clean and free of infection now.
Here’s what happens next — and this is the part that sounds almost too simple to be real.
I use a small file to gently irritate the tissue just beyond the tip of the root. This causes a small amount of bleeding into the canal. That blood forms a clot inside the tooth.
That blood clot is the magic ingredient.
It’s packed with stem cells from a region called the apical papilla — a cluster of cells that sits right at the tip of a developing root. It also carries growth factors and scaffolding proteins that tell those stem cells what to do. Build tissue. Form new root structure. Grow.
Once the blood clot is in place, I seal over the top of it with a biocompatible material and close the tooth up. And then we wait.
The Waiting Game
This is where the body takes over. Over the next several months — and sometimes up to a year or more — the stem cells in that blood clot get to work. New tissue grows inside the canal. The root walls get thicker. The root gets longer. The open apex gradually narrows and closes.
We monitor everything with periodic X-rays. And what you see on those X-rays is honestly remarkable. A root that was once short and thin starts looking like a normal, healthy, fully developed root.
The tooth didn’t just survive. It grew up.
The Science Behind It (Without the Textbook Talk)
So why does this work?
It comes down to three things: stem cells, growth factors, and a scaffold.
Stem cells from the apical papilla are special. They can turn into different types of cells — the kind that make dentin (the hard stuff your tooth is made of), the kind that make cementum (the coating on the root surface), and even cells that form new blood vessels. These stem cells are most active in young patients, which is a big part of why this procedure works so well in kids and teens.
Growth factors are signaling molecules found in the blood clot (and also released from the dentin walls of the canal itself). They tell the stem cells where to go and what to become. Think of them as the construction blueprints.
The scaffold is the blood clot. It gives the stem cells a physical structure to grab onto and organize around. Without it, the cells would have nothing to build on. The clot gives them a framework.
Put all three together inside a clean, sealed environment, and the body does what it already knows how to do — heal and grow.
What the research shows: Studies published in the Journal of Endodontics have documented continued root development in the majority of regenerative cases, with thickening of root walls and closure of the apex. Some cases even show a return of nerve response — meaning the tooth might regain some ability to feel sensations.
What About the Results?
The outcomes we see are really encouraging.
In most successful cases:
- Root walls thicken — the tooth becomes structurally stronger
- Root length increases — the root continues growing toward its normal length
- The apex closes — that wide-open tip narrows and seals itself
- Some patients regain sensitivity — positive responses to cold testing, suggesting new nerve tissue has formed
Not every case is a home run. Sometimes the root walls thicken but the root doesn’t get much longer. Sometimes the apex closes but there’s no return of sensation. And occasionally, if the infection was too severe or the stem cells don’t respond, we may need to fall back on traditional methods.
But compared to the old approach — where the best-case scenario was a fragile tooth with an artificial plug — regenerative endodontics is a massive step forward.
The Limitations (I’ll Be Straight With You)
This procedure has real boundaries, and I think it’s fair to be upfront about them.
It works best in young patients. The stem cells in the apical papilla are most plentiful and active in kids and teens. As you get older, that cell population shrinks. By the time you’re an adult with fully formed roots, the regenerative potential just isn’t the same.
It’s not a replacement for root canals in adults. If you’re 35 with a fully developed tooth that needs treatment, a traditional root canal is still your best bet. Regenerative endodontics isn’t designed for that situation — at least not yet.
The tooth may not be exactly the same as an untouched tooth. The tissue that grows back isn’t always identical to normal pulp. Histological studies (where researchers look at the tissue under a microscope) have shown that what regrows is often a mix of cementum-like and bone-like tissue rather than true dental pulp. It works. It strengthens the tooth. But it’s not a perfect biological reset.
Compliance matters. We need kids to come back for follow-up appointments so we can track progress. Parents in the Torrance and South Bay area — I can’t stress this enough — those recall visits are how we catch problems early and confirm everything is heading in the right direction.
Where Is Regenerative Endodontics Heading?
This is where it gets really exciting.
Researchers are working on ways to extend regenerative techniques to adult teeth. Some labs are experimenting with injectable scaffolds seeded with stem cells. Others are exploring gene therapy approaches to reactivate dormant stem cell populations in mature teeth. There’s even research into bioengineered tooth constructs — growing replacement teeth from scratch.
We’re not there yet. But the foundation being laid by regenerative endodontics in young patients is paving the road for treatments that could change how we handle tooth damage in people of all ages.
Within the next decade, the question might shift from “Can we save this tooth?” to “Can we regrow this tooth?” That’s a big deal.
Why an Endodontist Should Do This — Not Just Any Dentist
Regenerative endodontics is a specialized procedure. It requires:
- A dental microscope — to see inside tiny, developing canals with precision
- CBCT 3D imaging — to evaluate root development, check for fractures, and monitor healing over time
- Specific training in regenerative protocols — knowing exactly how much to disinfect, when to induce bleeding, and how to seal the tooth for the best outcome
- Experience managing complications — because things don’t always go as planned, and you need someone who can pivot
Pediatric dentists are fantastic at what they do. But regenerative endodontics falls squarely in the endodontist’s wheelhouse. This is root canal-level work on the inside of the tooth. It’s what we’re trained for.
At our Torrance office, I have the microscope, the CBCT scanner, and the hands-on experience with these cases. When a kid comes in with a knocked-out nerve and an unfinished root, this is exactly the kind of problem I want to solve.
Your Kid Took a Hit to the Mouth — Now What?
If your child has had a dental injury — or if their dentist has told you the nerve in a permanent tooth has died — don’t assume a standard root canal is the only path forward. If the root isn’t fully formed, regenerative endodontics might be the better option.
Here’s what to do:
- See your dentist first for an initial evaluation
- Ask for a referral to an endodontist — specifically one experienced in regenerative procedures
- Get a consultation so you can see the X-rays, understand the root development, and talk through the options
We see families from across the South Bay — Torrance, Redondo Beach, Palos Verdes, Hermosa Beach, Manhattan Beach — and we’re always happy to take a look and give you an honest answer about what’s possible.
Call (310) 378-8342 to schedule a consultation at Phan Endodontic Partners. If your child’s tooth has a chance to keep growing, let’s not miss that window.