There are a couple different situations that will cause teeth to crack, but all of them stem from the layers of enamel and dentin in teeth drying/expanding unevenly. We will go over a few different scenarios that are likely to increase your chances of experience teeth cracking, how to best prevent it, and how to repair/stabilize cracked teeth.

What Materials are Needed to Prevent/Repair Cracked Teeth?

1. Hygrometer

2. Humidifier

3. Epoxy or Super Glue

4. Accelerator for Super Glue

Cause 1: Heat

Extreme heat is the main reason that most people will tell you that teeth crack, but it usually is not the main case. If you use boiling to clean skulls (PSA: Don’t do that, See How to Clean Bones with Water), it is possible that the heat will cause the softer dentin layer of teeth to expand quicker than the outer, harder layer of enamel. This can cause hairline fractures that will increase in size in time due to the next cause.

Simple solution: Don’t use boiling/simmering temperatures during any step of processing.

Cause 2: Low Humidity

Uneven or accelerated drying of the layers of teeth is the main cause for teeth cracking, especially canines. If you live in the arid West, or leave your skulls outside in the sun to dry, this is most likely the cause of your cracking teeth. 

The first step is to get a Hygrometer. The one I linked measures temperature and humidity, as well as shows you the high and low of each in the last 24 hours. It comes with a magnet on the back or a kickstand for easy display. Simply put it wherever you store your bones and give it at least a few hours to give you an accurate reading. If it is reading less than 35% humidity, there is your problem. I’ve found that 40-50% humidity is ideal.

Setting up a humidifier wherever you clean/dry/store skulls will probably be the easiest way to increase your humidity. Refilling the humidifier every few days will definitely be a burden, but if it stops teeth from cracking it’ll likely be worth it. I couldn’t find a humidifier that can automatically be hooked up to a water line so you don’t have to refill it, but perhaps they exist! Look around!

How to Repair Cracked Teeth

If the damage has already been done, don’t fret! It’s not too terribly hard to repair cracked teeth, and most of the time the repair job will hardly be seen. Canines are the most common tooth to crack, so I will focus on those for demonstration purposes. It is important to not repair cracked teeth until the end of processing (after defleshing, degreasing, and whitening) to ensure that our repair job holds up.

Method 1: If possible, remove the cracked teeth from the skull. If the crack runs all the way up the canine, simply split the tooth in half and then apply some superglue to the inside of the tooth, making sure to line up the parts of the tooth that will be visible as well as you can.

Then, simply hold closed and apply the Superglue Accelerator. This will dry the super glue in only a couple seconds. You can allow the crack to show up in the root portion if you need to, that won’t be seen once you glue the tooth back in the skull. 

After that, simply wipe off excess visible superglue with a scalpel or a little bit of acetone.

Purposefully split the cracked tooth in half to clean the inside and be able to line up the edges better before gluing

Method 2: If you cannot remove the cracked teeth from the skull, still use superglue inside the crack, but holding the tooth together while applying accelerator may be more difficult.

Method 3: If you’re working on large animals (bear, pig, big cats, etc), a different approach can be used. This works particularly well in animals with tusks or other ever-growing teeth (such as boar, warthogs, beavers, etc). You’ll need to extract the tooth/tusk in order to do this. 

If it’s a tooth with a closed root (i.e. you can’t see into the end of it), you’ll need to cut/drill the end to expose the hollow center. Once the hollow center is visible, simply fill the inside of the tooth with two-part epoxy or superglue. 

If using epoxy, just mix equal parts together, then make sure it gets deep into the tooth. If using superglue, fill it up then spray with accelerator. 

Make sure to keep the cracked tooth clamped during the drying process so none leaks out. This method holds the tooth together very tightly, and drastically reduces the chances of it cracking again in the future.

What Now?

Enjoy your skulls with perfect teeth!