A Knocked-Out Tooth: The First 30 Minutes Decide Everything

A tooth on wet decking looks much smaller than you expect. That is the detail I still remember from a July afternoon at a camp near Workum: a fifteen-year-old with blood on his chin, and a whole upper front tooth lying on the boards with the root attached and pale.

Our first-aid kit had a burn dressing, three sizes of plaster and a foil blanket. Nothing in it was any use. What I did over the next ten minutes was wrong in almost every way it could be, and that tooth did not survive. Six years later a different student lost one in front of me, we handled it properly, and she still has it. The difference between those two afternoons came down to about four things, and none of them are complicated.

I am not a dentist or any kind of medical professional. This is the plain version of what emergency dental guidance says, filtered through having stood there twice.

Why the clock is so tight

A tooth is not cemented into the jaw. It hangs in the socket on a thin layer of living fibres called the periodontal ligament. When the tooth comes out, some of those cells stay stuck to the root surface, and they are the reason a tooth can reattach at all. They begin dying within minutes of drying out. The figure I was given afterwards is that once a tooth has been dry for about thirty minutes the odds fall off a cliff, and past an hour you are usually looking at a worse outcome even if it goes back in.

So the whole of that first half hour is really about one question: are those cells still alive? Cold, wet and undisturbed means yes, for a while. Dry, scrubbed, or rattling loose in a jacket pocket means no.

The order of operations

• Find the tooth. Pick it up by the crown, the chewing part. Never touch the root.
• If it is dirty, rinse it for a couple of seconds in milk or saline. Do not scrub it, do not use soap, do not wipe it dry.
• If you can, push it straight back into the socket the right way round, then have the person bite gently on a clean cloth to hold it there.
• If you cannot, put it into cold milk. Saline works too. The person's own saliva, tooth held inside the cheek, is a distant third and not an option for a child who might swallow it.
• Get to a dentist or an emergency department inside the hour, with the tooth.

That is the whole thing. Everything else is noise. The American Dental Association material on dental trauma covers the same ground in more clinical language if you want the fuller version.

The four things I got wrong the first time

I rinsed it under a tap, because that is what you do with a cut. Tap water is the wrong saltiness and it destroys those ligament cells faster than almost anything else available to you. I then wiped the root with a paper towel, which physically scrapes the cells off. I wrapped it in a dry tissue for the drive, which is the same as leaving it on a windowsill for twenty minutes. And I did not put it back in the socket, because pushing a tooth into a bleeding teenager felt like a job for someone with a licence. It is not. Immediate replanting is the best thing available at the scene, and every set of guidance I have read since says so plainly. The NHS page on a broken or knocked-out tooth is short, and I wish I had read it in 2017 rather than 2019.

Milk, and the one exception

Milk is not magic. It just happens to be roughly the right saltiness and acidity for those cells, it is cold, it is clean, and you can buy it at a petrol station at any hour of the night. Whole or semi-skimmed makes little difference. Long-life cartons are what I carry now, because a small sealed one sits in a dry bag for a year without complaining. The rest of what I keep in that bag is in my notes on dental injuries out on the water.

Do not use water. Do not use a sports drink, which is acidic enough to be actively hostile to what you are trying to save. Do not use disinfectant of any kind. If you truly have nothing, saliva buys you time, but only for an adult who is fully awake and in no danger of swallowing the thing.

There is one exception to everything above, and it matters. A knocked-out baby tooth does not go back in. Pushing it back can damage the adult tooth developing above it. The child still needs to be seen quickly, but you are not racing a thirty-minute clock with a carton of milk. Telling which is which is not always obvious with a panicking eight-year-old in front of you, so if you are unsure, bring the tooth along and let someone qualified make the call.

What I do now

Every course I ran after that first incident started with sixty seconds on this. Not a lecture, just: if a tooth comes out, milk, do not scrub it, shout for me. It cost nothing. When it happened again, on a windy afternoon with two staff and eleven kids, three people moved at once and the tooth was in cold milk inside ninety seconds. She was in a chair within forty minutes, it was splinted, it took, and last I heard it was still doing its job three years later.

One honest caveat about that. Replanted teeth do not always survive long term, even when everything is done right. Some resorb, some need root canal treatment later, some fail after years. Doing it properly buys a real chance, not a guarantee. It is still worth every second, because the alternative is a gap in the front of a teenager's face and decades of restoration work behind it.

Most of this is preventable, which is a slightly irritating thing to write at the end of a piece like this. A guard that actually stays in your mouth is the reason the third and fourth incidents on my watch never happened, and I have made the full argument for guards and what they are worth elsewhere. I would rather you read that one and never need this one.