While cracked teeth are not completely preventable, you can take some steps to make your teeth less susceptible to cracks.
Don't chew on hard objects such as ice, unpopped popcorn kernels or pens.
Don't clench or grind your teeth.
If you clench or grind your teeth while you sleep, talk to your dentist about getting a retainer or other mouthguard to protect your teeth.
Wear a mouthguard or a mask when playing contact sports.