A dental first aid kit will not repair a tooth, and it is not supposed to. Its job is to hold a situation steady until you can be seen. The single most valuable item in it is not a gadget. It is milk. If an adult tooth is knocked out, the International Association of Dental Traumatology lists milk at the top of the storage media you should use, and after about 30 minutes of dry time outside the mouth most of the ligament cells on the root are already dead. A carton of long life milk in the pantry does more for that tooth than anything else you could buy.
Key takeaways
- Extra-oral dry time is the single most important factor for whether a knocked out adult tooth survives long term.
- Suitable storage media in order of preference are milk, Hank's Balanced Salt Solution, saliva, then saline. Water is not on the list at all.
- Milk is generally acceptable for up to about 60 minutes, and cool milk works better than warm.
- Never try to put a knocked out baby tooth back in. That one rule is different for children.
- Temporary filling material is a bridge to a dentist, not a repair, and eugenol containing products can interfere with the permanent filling later.
- No trial has ever tested a home dental kit as a whole, so treat the contents list as sensible rather than proven.
What this kit is for, and what it is not
We already have an article on at home tooth repair kits and whether they work. That one is about the products sold as a way to fix your own tooth, and the answer there is mostly no. This article is a different question. It is about what to keep in the house so that when something happens at 9pm on a Saturday, you can stop the bleeding, protect the tooth, ease the pain and get to a dentist without having made things worse.
The distinction matters, because the two get confused constantly. Nothing here is a treatment. Every item buys time, and the tooth still needs a dentist.
The most important item is milk
If a permanent tooth is knocked clean out, the cells on the root surface, called periodontal ligament cells, decide the tooth's long term fate. Keep them alive and the tooth can be replanted and can reattach. Let them dry out and the tooth tends to fuse to the bone over the following years, a process called ankylosis, and eventually fails. The guideline names extra-oral dry time as the single most important factor for that outcome.
After about 30 minutes of dry time, most of those cells are no longer viable. That is why the best move is always to replant the tooth immediately if you can. If you cannot, storage medium becomes the priority, and milk is generally regarded as acceptable for up to about 60 minutes. Cool milk is better than room temperature, because it reduces swelling and improves cell survival. A systematic review found milk extends periodontal ligament cell viability compared with saline or tap water. In laboratory work at 5 degrees Celsius over 3 to 120 hours, skimmed and whole milk performed best, followed by coconut water and Hank's Balanced Salt Solution.
Hank's solution is the medium used in commercial tooth rescue kits, because it is pH 7.4 with an osmolality of around 280 mOsm per litre and carries essential nutrients. I am not going to tell you those kits are sitting on the shelf at your local Australian pharmacy, because I have not verified that. Milk is the realistic option in an Australian kitchen, and it works.
Water is the worst choice, which surprises people, because it feels like the clean option. Water is hypotonic and non-physiological, so the cells swell and burst. It is not on the guideline list for a reason. Saliva, meaning holding the tooth in the cheek or spitting into a container, is better than water.
Two rules people get wrong
Hold the tooth by the crown, the chewing part, never by the root, and do not scrub it. If it is visibly dirty, rinse it briefly with milk or saline and leave the soft tissue on the root alone. And never replant a knocked out baby tooth, because forcing it back can damage the developing adult tooth underneath. Our full step by step protocol is in the article on first aid for a knocked out tooth, and the storage question is covered in more depth in storing an avulsed tooth in milk.
What to keep in the kit
| Item | What it is for | What the evidence says | What it will not do |
|---|---|---|---|
| Long life milk, plus fresh milk in the fridge | Storing a knocked out adult tooth on the way to the dentist | Top of the guideline list, and shown to extend ligament cell viability compared with saline or tap water | Will not preserve a tooth indefinitely. Treat about 60 minutes as the window |
| Small clean container with a lid | Holding the tooth in milk without it rolling around the car | No trial evidence, simply practical. Cool storage improves cell survival | Will not help if the lid leaks or the tooth dried out first |
| Sterile gauze squares | Firm pressure on a bleeding socket or a bitten lip | Direct pressure is the standard first response to bleeding | Will not stop bleeding caused by a clotting problem |
| Sterile saline | Rinsing a wound gently, and as a fallback storage medium | Listed in the guideline below milk and saliva, so acceptable rather than ideal | Will not preserve ligament cells as well as milk |
| Non medicated orthodontic wax | Covering a poking wire or a sharp broken edge | Widely recommended for orthodontic irritation and carries essentially no risk | Will not fix the wire, and will not survive a meal |
| Temporary filling material | Bridging a lost filling for a day or two | Zinc oxide eugenol is bacteriostatic, antiseptic and well tolerated by pulp | Poor mechanical strength, and eugenol interferes with later bonding |
| Painkillers you already tolerate | Controlling pain until you are seen | Standard analgesia works for most dental pain of ordinary severity | Will not treat the infection, and masking pain can delay the visit |
| Cold pack | Reducing swelling and bruising after a knock to the face | Routine advice for facial trauma and post-operative swelling | Will not reduce swelling caused by spreading infection |
| Written contact plan | Knowing who to ring, and what to do after hours | Delay is the enemy in dental trauma | Will not help if it is only on a phone that is flat |
Bleeding, gauze and the 20 minute rule
Most bleeding after an extraction or a bitten lip responds to one thing done properly. Roll gauze into a firm pad, place it directly over the bleeding point rather than beside it, and bite or press for a full 20 minutes without looking. Lifting the pad every two minutes to check is the most common reason bleeding continues. Sit upright, avoid hot drinks, do not rinse and do not smoke.
Soft tissue injuries from a fall or a sporting knock are their own category, and lips and tongues bleed impressively out of proportion to the damage. Our article on first aid for a bitten tongue, lip or cheek goes through when a wound needs stitching and when it does not.
Temporary filling material and the eugenol problem
Over the counter temporary filling materials usually contain zinc oxide eugenol. It is bacteriostatic, antiseptic and kind to pulp tissue, which is why dentists have used it for a very long time. It also has poor mechanical properties, so it is temporary by design and will crumble under a proper bite.
The catch is worth knowing before you use it. Eugenol interferes with the bonding of resin composite afterwards and increases the contraction gap at the margin. In plain terms, packing eugenol into a cavity can make the permanent white filling that follows slightly less reliable. Use it if you have a sharp edge or an open cavity that is agony to air, use as little as possible, and tell the dentist what you put in there.
What not to do is pack a hole with chewing gum, candle wax or household adhesive. I have seen all three, and none of them are harmless.
What the evidence does not tell us
I want to be straight about the quality of what sits behind this. The storage media data are almost entirely in vitro cell viability work, meaning cells in a dish rather than teeth in patients, and clinical replantation outcome studies are thin. The 30 minute figure for dry time and the 60 minute figure for milk get conflated constantly online, including in places that should know better. They describe different things. Dry time is the clock that really matters, and milk slows that clock rather than stopping it.
No trial has tested a home dental first aid kit as a whole either. What we have is decent evidence for individual components and sensible reasoning for the rest. That justifies a small box in the cupboard, not an expensive one.
When the kit is not the answer
Call 000 or go straight to a hospital emergency department if you have any difficulty breathing, difficulty or pain on swallowing, swelling under the jaw or in the floor of the mouth, swelling that is closing your eye, a fever with spreading facial swelling, a suspected broken jaw, or bleeding you cannot control after 20 minutes of firm continuous pressure. None of those are first aid kit problems. They are time critical and they can involve the airway. Do not wait for morning and do not wait to see whether it settles.
Short of that, ring a dentist the same day for a knocked out or displaced adult tooth, a tooth that has been pushed out of position, a rapidly worsening toothache, or swelling around a tooth. Our guide to dental emergencies sets out which problems need to be seen within hours and which can reasonably wait a day or two.
Where to keep it and how to maintain it
One box, somewhere everyone in the house knows about, near the standard first aid kit rather than hidden in a bathroom drawer. If you have children playing contact sport, a second small version in the sports bag is worth it. Check the expiry on the saline and the long life milk twice a year, and replace the temporary filling material if it has gone hard in the pot. Add a custom mouthguard to the same checklist if anyone plays a collision sport, because preventing the injury beats storing the tooth in milk afterwards.
Common questions
Can I put a knocked out tooth in water?
No. Water is hypotonic, so the cells on the root surface swell and burst, and it is deliberately left off the guideline list. Milk is the first choice, then Hank's Balanced Salt Solution, then saliva, then saline. If you have nothing else, holding the tooth inside the cheek is better than water, provided the person is conscious and will not swallow it.
How long can a tooth survive in milk?
Treat about 60 minutes as the working window for milk, and keep it cool. That is not a hard cut off, and teeth stored longer have still been replanted, but the chance of a good long term result falls with time. The clock that matters most is dry time, so get the tooth into milk as fast as you can.
What should be in a dental first aid kit at home?
Milk, a small clean container, sterile gauze, saline, non medicated orthodontic wax, a temporary filling material, a cold pack, painkillers you already tolerate, and your dentist's contact details written down. That covers the situations that actually happen. Anything beyond that is usually marketing.
Can I glue my crown back on at home?
Do not use household glue. It is not designed for the mouth, it can damage the tooth underneath and it can make the crown unusable, which turns a cheap re-cement into a new crown. A temporary dental cement from a pharmacy is acceptable for a day or two, and even then the crown needs to be checked and properly cemented.
The best version of dental first aid is not needing it. Regular check ups pick up the cracks, the leaking fillings and the failing crowns that tend to break at the worst possible moment. The team at Lumi Dental in Melrose Park is open Monday to Saturday, with Sunday by appointment, and can talk you through what to keep at home for your family. New patients can see what is currently available on our current deals page.
This article is general information only. It is not personal dental or medical advice, and it cannot account for your own history, medicines or examination findings. Please see a dentist or your doctor about your own situation.
