Last Updated on 15/09/2026 by Dr Chetan Kaher
Dental emergencies never happen at a convenient time. It’s always mid-meal, mid-match, or somewhere between waking up and getting out the door, and the panic that follows tends to make people do the same thing with every kind of injury, when actually, what you do in the first 30 minutes depends entirely on what’s happened.
A knocked-out tooth needs a completely different response than a cracked crown, and both are worlds apart from a lost filling. Treating them all the same way, or worse, waiting to see if it settles down, can turn a fixable situation into a harder one. Here’s what actually matters for each, and when it’s genuinely time to call an emergency dentist in St John’s Wood rather than wait it out.
A knocked-out tooth: minutes genuinely count
This is the one where speed makes the biggest difference to the outcome. If a tooth’s been knocked out completely, root and all, the window to save it is short, ideally within the hour.
Pick the tooth up by the crown, not the root, the root has delicate tissue on it that you don’t want to touch or scrub off. If it’s dirty, a quick rinse with milk or your own saliva is fine, but don’t scrub it or use soap or water. If you can, gently pop it back into the socket facing the right way and hold it there. If that’s not possible, keep it in a small container of milk, not water, and get to an emergency dentist in St John’s Wood as quickly as you can.
This is genuinely the one dental emergency where “wait and see” isn’t an option. The longer the tooth is out of the socket, the lower the chance it can be successfully replanted.
A cracked or broken crown: less urgent, but not something to ignore
A cracked crown feels alarming, especially if it happens mid-meal and you’re suddenly aware of a rough edge where a smooth tooth used to be. The good news is this one rarely needs the same immediate rush as a knocked-out tooth. The crown itself isn’t a living part of your mouth, so there’s no biological clock ticking the way there is with a tooth root.
That said, don’t leave it too long. A cracked crown exposes the tooth underneath to bacteria, temperature changes, and pressure it’s not designed to handle on its own. If you can, keep the broken piece somewhere safe, sometimes it can be reattached. In the meantime, avoid chewing on that side and steer clear of anything very hot, cold, or sticky. Booking with an emergency dentist in St John’s Wood within a day or two is usually the right pace here, sooner if you’re in real pain, but it’s not a race against the clock the way a knocked-out tooth is.
A lost filling: uncomfortable, rarely urgent
Out of the three, a lost filling is generally the least time-pressured, even though it can feel the most immediately annoying. You’ll usually notice it because of a sudden rough patch or sensitivity where the filling used to be, sometimes triggered by biting down on something unexpectedly hard.
There’s no biological reason to treat this as a same-hour emergency. The main risk is the exposed area picking up food debris or becoming sensitive to temperature, so keeping the area as clean as you comfortably can, and avoiding chewing directly on it, is enough to manage things for a day or two. Over-the-counter dental cement from a pharmacy can offer temporary relief if the gap is bothering you, though it’s not a substitute for getting it properly refilled. This is a case where booking an appointment with an emergency dentist in St John’s Wood within a few days is sensible, rather than treating it as a middle-of-the-night crisis.
Why lumping these together causes problems
The reason this distinction matters is that a lot of people either panic unnecessarily over a lost filling, or don’t panic enough over a knocked-out tooth. Both reactions cause problems. Rushing to an emergency dentist in St John’s Wood at 2 am for a chipped filling isn’t necessary and isn’t always possible anyway. But treating a knocked-out tooth with the same “I’ll deal with it tomorrow” approach can mean losing the chance to save it altogether.
What to actually do in the moment
If it’s a knocked-out tooth, act within the hour if you possibly can. If it’s a cracked crown, protect it, avoid that side, and get seen within a day or two. If it’s a lost filling, manage the sensitivity and book in when it suits you, ideally within the week.
At Smile Cliniq, our associate dentist Dr Sarah Bux and the rest of the team would always rather get a call and talk you through what you’re dealing with than have you guess and either panic unnecessarily or wait too long. If you’re ever unsure which category your situation falls into, that’s exactly the kind of question worth asking before deciding what to do next.
Our St John’s Wood practice is at 102 Boundary Road, London NW8 0RH. Call 020 7328 1200 or email sjw@smilecliniq.com. We’re open Monday 8am to 8pm, Tuesday 8am to 6pm, Wednesday 8am to 5pm, Thursday to Saturday 8am to 6pm, Sunday closed.
Frequently asked questions
How long can a knocked-out tooth survive outside the mouth?
The best chance of saving it is within the hour, kept in milk or gently reinserted into the socket. The longer it’s out, the lower the odds of a successful replant.
Do I need to see an emergency dentist for a lost filling straight away?
Not usually. A lost filling is uncomfortable but rarely urgent. Keep the area clean, avoid chewing on it, and book within a few days rather than treating it as a middle-of-the-night crisis.
What should I do with a piece of a broken crown?
Keep it somewhere safe if you can. Sometimes it can be reattached. Avoid chewing on that side and book an appointment within a day or two.
