Six Months After the Fall, the Tooth Started Going Grey

Quick answer: A permanent tooth that darkens months after an injury has usually lost its nerve. In a child whose root is not yet fully formed, this needs a different technique from an adult root canal — the root end is open and cannot be sealed conventionally.

The call

Yehuda, 9, from Beit Shemesh, had knocked his front tooth on a doorframe the previous winter. He had been seen at the time, the tooth had been firm and had tested normally, and everyone had moved on.

His mother noticed the colour at a family simcha, in photographs. One upper front tooth was clearly darker than its neighbour.

She phoned expecting to be told it was nothing. It was not nothing, and she was right to phone.

What we found

The upper right central incisor was a distinctly greyish shade compared with the tooth beside it. No pain, no swelling, no tenderness.

Testing: no response to cold, no response to electric pulp testing, while every neighbouring tooth responded normally. The x-ray showed a small dark area beginning at the root tip, and — the crucial finding — the root canal was noticeably wider than its neighbour and the root end was still open and funnel-shaped.

Permanent front teeth erupt at around seven, but their roots take a further two to three years to finish forming. The nerve does that work. Yehuda's tooth had been knocked at eight and a half; the nerve had died shortly afterwards, and root formation had stopped at that moment. The root was short, thin-walled, and open at the tip like a trumpet.

That changes the treatment entirely. A conventional root canal relies on a natural narrowing at the root tip to pack the filling against. With an open apex there is nothing to pack against — filling material simply extrudes into the bone.

Two approaches:

Apexification. Create an artificial barrier at the root end using a calcium-silicate material, then fill above it. Reliable, well established, achievable in one or two visits with modern materials. The root stays short and thin-walled, which means a lifelong fracture risk.

Regenerative endodontics (revascularisation). Disinfect the canal without instrumenting it, induce bleeding from the tissue beyond the root tip to form a scaffold inside the canal, and seal it. In favourable cases the root continues to thicken and lengthen. More biologically appealing, less predictable, and best suited to younger children with wider open apices and no infection.

What we did

We discussed both honestly. Given the established lesion at the root tip and the degree of root development already achieved, we chose apexification.

Access, careful disinfection without aggressive filing — the walls were thin and easily perforated — calcium hydroxide dressing for four weeks to settle the infection, then a calcium-silicate plug placed at the root end under magnification and the rest of the canal filled.

Restored with bonded composite, deliberately keeping the access small to preserve as much tooth as possible.

We also bleached the tooth internally over three visits once the root filling was sealed, which brought the colour back close to its neighbour.

The outcome

The lesion at the root tip healed over eighteen months. The colour matches well.

He has been told two things clearly. The tooth is more fragile than a normal one because the root is thin, so he wears a mouthguard for sport and avoids biting hard things with it. And it will need reviewing for the rest of his life.

What to do if this happens to you

1. Take colour change seriously, however long after the injury.
2. Compare in daylight, next to the matching tooth on the other side.
3. Photograph injured teeth every few months for the first two years. Gradual change is hard to see day to day.
4. Keep every follow-up appointment, even when the tooth seems fine.
5. Ask whether the root is fully formed. It determines which treatment is possible.
6. Expect lifelong monitoring for any tooth that has had a significant injury as a child.

Child's tooth changing colour after an injury? Ramat Beit Shemesh Urgent Dental Care tests and monitors traumatised teeth. 055-985-8845 · WhatsApp https://wa.me/972559858845 · Harav Kook 28/1, Beit Shemesh.

Based on real cases treated at the clinic. Names have been changed.