What Should I Do About a Knocked-Out Tooth?
Pick it up by the crown, never the root. Do not scrub it. If you can, push it gently back into the socket straight away and bite on a clean cloth — that gives it the best chance by a wide margin. If you cannot, keep it in milk, not water, and be seen within the hour. For a knocked-out baby tooth, do the opposite: do not put it back.
Why the first minutes decide it
The root of a tooth is covered in a thin layer of living cells, the periodontal ligament. Those cells are what let a replanted tooth knit back into the bone. They are also fragile: they begin to die within minutes of drying out, and once they are gone the tooth may hold for a while but tends to fuse to the bone and be lost later.
That is the whole reason the advice is what it is. Everything below is about keeping those cells alive until the tooth is back where it belongs. Replanted within about fifteen minutes, the outlook is good. After an hour out of the mouth and dry, it is poor. Getting the tooth back in beats getting to a dentist fast — and you can do the first part yourself.
Handling it
Hold it by the crown. The crown is the part that normally shows in the mouth. Fingers on the root wipe off the cells you are trying to protect.
Do not scrub, scrape or disinfect it. No toothbrush, no soap, no antiseptic. If it is visibly dirty, rinse it for a few seconds in milk or saline. If it looks clean, do not rinse it at all.
Put it back if you can. Line it up the right way round and press it gently into the socket until it sits level with its neighbours. Then bite softly on a clean cloth or a handkerchief to hold it there.
If you cannot, keep it wet. Milk is the easiest good option. Saline works. An adult can hold the tooth inside the cheek, where saliva keeps it moist, provided there is no chance of swallowing it.
Why not water
Water seems like the obvious choice and is the one thing to avoid. It is far less salty than the fluid the cells are used to, so they swell and burst. A tooth carried to the clinic in a glass of water has usually lost the thing that would have let it reattach.
Milk is close enough in salt content and acidity to keep those cells going for a few hours, which is why it is the standard advice despite sounding odd.
A baby tooth is different
This is the one situation where the advice reverses, so it is worth knowing before it happens. A knocked-out baby tooth is not put back. The adult tooth is developing in the bone directly above it, and pushing the baby tooth back risks damaging it.
Take your child to be seen, and bring the tooth so it can be accounted for — it matters that it is not somewhere it should not be, such as inhaled or buried in the lip. The gap itself is usually managed rather than filled.
What happens when you are seen
The tooth is checked for position, the socket and surrounding bone are examined, and an X-ray confirms there is no fracture of the root or the bone around it. A replanted tooth is then splinted to the teeth either side for a short period while the ligament reattaches.
Root canal treatment usually follows for an adult tooth with a fully formed root, because the blood supply is severed at the moment of injury and does not reconnect. It is done after the tooth is stable rather than on the day. A tooth whose root is still forming may keep its nerve, so those are watched first.
If the injury involved a blow to the face, a dirty surface, or you are unsure when you last had a tetanus booster, mention it — that may need a doctor rather than a dentist.
If it happens
Do the tooth part first: back in the socket, or into milk. Then call us on 6443 9509 and say a tooth has been knocked out, so the time is understood from the first sentence. The rest of what we hold for patients in pain is on the emergency page.
Facial swelling, difficulty swallowing or breathing, uncontrolled bleeding, or a suspected jaw fracture are hospital problems rather than dental ones. Go to an emergency department.
Questions
Can a knocked-out tooth really be put back?
Often, yes, if it is an adult tooth and it goes back quickly. The cells on the root surface are what allow it to reattach, and they do not survive long outside the mouth. Reimplanted within about fifteen minutes the outlook is good; after an hour dry it is poor. That is why the first few minutes matter more than how fast you can reach a clinic.
Why not rinse it under the tap?
Tap water destroys the living cells on the root surface, which are exactly what you are trying to keep. If the tooth is visibly dirty, rinse it briefly in milk or saline instead, and only for a few seconds. If it is clean, do not rinse it at all.
What if I cannot put it back in?
Keep it wet in milk and get seen quickly. Saline works, and so does the patient's own saliva — an adult can hold it inside the cheek if there is no risk of swallowing it. Do not use water, and do not let it dry out on a tissue or in a pocket.
My child knocked out a baby tooth. Same thing?
No, and this is the one place the advice reverses. A knocked-out baby tooth is not put back, because reimplanting it can damage the adult tooth developing above it. Take your child to be seen, bring the tooth so it can be accounted for, but do not push it back into the socket.
Will the tooth need a root canal afterwards?
Usually, for an adult tooth with a fully formed root. The blood supply is cut at the moment of the injury and does not reconnect, so the nerve is treated after the tooth has been stabilised rather than at the same appointment. Teeth with roots still forming are watched first, because some recover.