If a tooth gets knocked out, you have roughly 5 minutes for the best chance of saving it, and every minute beyond that reduces the odds. The single most important thing you can do is get the tooth into milk or back into its socket as fast as possible. A knocked-out permanent tooth that’s replanted quickly has about a 90% survival rate in the first six months. Wait too long and that number drops sharply.
Pick It Up by the Crown, Not the Root
The root of your tooth is covered in a thin layer of living cells called the periodontal ligament. These cells are what allow the tooth to reattach to the bone in your jaw. If you touch, scrub, or scrape the root, you destroy those cells and dramatically lower the chance of successful replantation.
Always hold the tooth by the crown, which is the white part you normally see in your mouth. If the tooth is dirty, give it a very gentle rinse under water for no more than a few seconds. Do not scrub it. Do not wrap it in a tissue or paper towel, which will dry out and damage those critical root cells.
Try to Put It Back In
The best place for a knocked-out tooth is right back in its socket. If you can do this within minutes of the injury, the tooth has its highest chance of survival. Hold the tooth by the crown, orient it the right way (use the matching tooth on the other side as a guide), and gently push it into the empty socket. Bite down softly on a clean cloth to hold it in place, then get to a dentist immediately.
This sounds intimidating, but it’s the single best thing you can do. The socket provides the perfect environment to keep those root cells alive.
The Best Storage Options If You Can’t Replant
Sometimes putting the tooth back in isn’t possible, especially with children who might swallow it, or when there’s too much bleeding or panic. In that case, you need to store the tooth in the right liquid. Not all liquids work equally well, and one common choice is actually harmful.
- Milk is the best widely available option. It has a similar chemical balance to what your cells need to survive, and it’s almost always nearby. Cold milk is ideal. Drop the tooth in a small cup or container and go.
- Hank’s Balanced Salt Solution (HBSS) is the gold standard in clinical settings. It’s sold in tooth-rescue kits (often branded as “Save-a-Tooth”). If a school, gym, or sports facility has one, use it. For teeth that have been out of the mouth for 20 minutes to 2 hours, soaking in HBSS for 30 minutes can rehydrate the root cells before replantation.
- Saliva works in a pinch. An adult can hold the tooth between their cheek and gum or under their tongue during transport. This isn’t ideal for children due to the swallowing risk.
- Saline solution (contact lens solution) is acceptable for short-term transport.
- Tap water is harmful. Plain water causes the root cells to swell and burst because of the difference in salt concentration. Even a few minutes in water significantly damages the ligament cells. Avoid it.
A systematic review of storage media studies found that milk was the most recommended option across 13 individual studies, followed by HBSS. The practical advantage of milk is obvious: it’s in almost every refrigerator.
Time Thresholds That Determine the Outcome
Speed matters more than almost anything else. Here’s how timing breaks down:
- Under 5 minutes: Best possible prognosis. The root cells are still fully alive.
- Under 20 minutes (kept moist): Very good odds. Get to a dentist as fast as you can.
- 20 to 60 minutes: Survival is still possible, especially if the tooth was stored in milk or HBSS. The dentist may soak the tooth in HBSS for 30 minutes to revive the root cells before replanting.
- Over 60 minutes dry: The root cells are almost certainly dead. Replantation may still be attempted, but the tooth will likely fuse directly to the bone (a condition called ankylosis) and eventually be reabsorbed. In younger patients, this process typically takes about 7 years. In adults over 16, the tooth may last considerably longer.
- Over 2 hours: There’s roughly a 95% chance of root resorption, meaning the body gradually breaks down the root.
Extraoral time over 15 minutes increases the risk of complications by about 1.7 times. Every minute counts.
How to Preserve a Broken Tooth Fragment
If your tooth chips or fractures rather than coming out entirely, the broken piece can sometimes be bonded back on by a dentist. The key is keeping the fragment hydrated. Drop it in milk or saliva, the same storage media recommended for a fully knocked-out tooth. Studies on fragment reattachment found that milk and saliva were the best storage environments for maintaining a strong bond when the piece is later glued back.
Don’t let the fragment dry out, and don’t try to clean it with soap or chemicals. Just rinse gently, store in milk, and bring it to your appointment. Even if the fragment can’t be reattached, it helps your dentist match the size and shape of a restoration.
Baby Teeth Are Handled Differently
If a child’s baby tooth gets knocked out, don’t try to put it back in. Current dental guidelines recommend against replanting primary teeth. Forcing a baby tooth back into its socket can damage the developing permanent tooth underneath. Clean the area gently, control any bleeding with light pressure, and see a pediatric dentist to make sure the adult tooth bud wasn’t harmed.
What Happens at the Dentist’s Office
Once you arrive with the tooth (ideally in milk, ideally within 30 minutes), the dentist will gently place it back into the socket if you haven’t already. They’ll then attach a small flexible splint, typically a thin wire bonded to the replanted tooth and the teeth on either side, to hold everything in place while healing begins.
For a straightforward replantation with no bone fracture, the splint usually stays on for 7 to 14 days. If there’s also a fracture in the surrounding bone, the splint may need to remain for 6 to 8 weeks. Late replantations, where the tooth was out of the mouth for an extended period, generally require about 5 weeks of splinting.
Your dentist will monitor the tooth with follow-up X-rays over the coming months and years, watching for signs of root resorption or ankylosis. Root canal treatment is often needed because the nerve inside the tooth typically doesn’t survive the trauma. The long-term survival rate for replanted teeth stabilizes at roughly 60% over several years of follow-up, with the best outcomes linked to short time outside the mouth and careful handling of the root.
Quick-Reference Checklist
- Pick up by the crown only. Never touch the root.
- Rinse gently if dirty. No scrubbing.
- Replant if possible. Push it gently back into the socket.
- If you can’t replant, drop it in cold milk immediately.
- Avoid tap water, tissues, and paper towels.
- Get to a dentist within 30 minutes for the best outcome.
- Bring any broken fragments stored in milk.
- Don’t replant baby teeth.