Knocked-Out Tooth: What to Do in the First 30 Minutes (and What Not to Do)

A knocked-out adult tooth has a real chance of survival if it's reimplanted within 30 minutes. After 60 minutes the success rate drops sharply. Here's what to do — fast — and what people commonly do wrong.

The 30-minute protocol

1. Find the tooth. Pick it up by the crown (the white part), not by the root. Touching the root damages the periodontal ligament cells that allow reattachment.
2. If dirty, rinse gently for 10 seconds with milk, saline, or saliva. Do not scrub. Do not use soap. Do not let it dry out.
3. Reimplant if possible. Place the tooth back in the socket the way it came out, push gently with your finger or thumb, then bite down on a clean cloth or gauze to hold it in place. This is by far the best storage medium.
4. If reimplantation isn't possible (e.g., person is unconscious, child too young, tooth damaged), store it in: cold milk (best), the patient's own saliva (place between cheek and gum), or saline solution. Water is the worst option — it actually damages the cells. Do not store in a tissue, on ice alone, or dry.
5. Get to a dentist within 30 minutes. If no dentist is open, the ER is the next stop, primarily for tetanus and trauma evaluation. They likely won't reimplant the tooth themselves, but they can stabilize you until a dentist is reachable.

Why time matters this much

The periodontal ligament is the tiny sheet of cells that connects a tooth's root to the bone. When a tooth is knocked out, those cells start dying within minutes. If they all die before the tooth is reimplanted, the tooth doesn't reattach properly — it eventually gets resorbed by the body and falls out again, sometimes years later.

Survival rates by reimplantation timing (rough averages from dental trauma literature):

• Reimplanted within 5 minutes: 90%+ chance of long-term success
• Reimplanted within 30 minutes: 50-80%
• Reimplanted between 30-60 minutes: 30-50%
• Reimplanted after 60 minutes: under 20%, often only briefly successful

Storage medium dramatically changes the curve:

• In the socket (best): cells protected by surrounding tissue
• Cold milk: cells survive 30-60 minutes
• Saliva or saline: cells survive 30 minutes
• Water: cells start dying within 15 minutes
• Dry: cells dead by 30-60 minutes

Common mistakes that ruin the chance of reimplantation

• Scrubbing the root — destroys the ligament cells
• Storing in tap water — osmotically lyses the cells
• Storing in tissue or paper towel — desiccates the cells
• Wrapping in ice — too cold, freezes cells
• Touching the root with bare fingers — contaminates and damages the ligament
• Waiting until morning to call — by then it's too late for reimplantation, only restorative options remain (implant, bridge, partial)

Baby teeth vs adult teeth

If a child knocks out a baby tooth, do not reimplant it. Reimplanting baby teeth can damage the developing adult tooth underneath. The baby tooth wasn't going to last anyway.

If you're not sure whether a knocked-out tooth is baby or adult: very small tooth (under 5mm long) and child under age 6-7 — likely baby. Larger tooth or older child — likely adult. When in doubt, save it in milk and let the dentist decide.

After reimplantation: what to expect

The dentist will splint the tooth to neighboring teeth for 1-2 weeks (or longer for severe cases). You'll need a soft diet during that time. A root canal is often required within a few weeks, because the blood supply to the tooth is usually disrupted.

Long-term, the tooth can last for years to decades. Some reimplanted teeth eventually undergo replacement resorption (the body slowly absorbs the root and replaces it with bone), but this can take 10+ years and is asymptomatic until very late. Others survive indefinitely.

Frequently asked questions

Can I reimplant a tooth myself?

Yes, and you should if you can. Push the tooth gently back into the socket the way it came out, then bite down on a clean cloth to hold it. The dentist will splint it properly later. The 30-minute window applies to whether the tooth gets back into a socket or appropriate storage — not whether a dentist personally does the reimplantation.

What if the tooth was knocked out yesterday?

After 24 hours, the chance of successful reimplantation is essentially zero. The tooth socket also begins healing closed. The discussion now shifts to replacement options: dental implant ($3,000-$5,000), bridge ($2,000-$4,000), or removable partial ($800-$2,000). See a dentist soon — the earlier you start, the more options remain.

Is Hank's Balanced Salt Solution worth keeping in a first-aid kit?

If you're a coach or athletic trainer, yes — Save-A-Tooth and similar products contain HBSS and keep tooth cells viable for 24 hours. For a household first-aid kit, milk is fine; you almost always have it available faster than you'd open a kit.

My tooth got pushed up into the gum, not knocked out — what should I do?

Don't try to pull it back down. An intruded tooth (pushed up) can be repositioned by the dentist, sometimes spontaneously re-erupting on its own in younger patients. Do see a dentist same-day — root canal is often eventually needed.

My child's permanent tooth was knocked out at school — what should the school nurse do?

Same protocol: pick up by crown, rinse if dirty, reimplant if possible (older children can often tolerate this), or store in milk and send the child immediately to a dentist or ER. Schools should have milk available; many also keep Save-A-Tooth kits.