Did you know that a canine tooth is the longest human tooth ever extracted? It was pulled from a boy in India last year and measured a whopping 1.44 inches! Just imagine how tough it would be to eat and speak with a tooth that long in your mouth. The tooth currently holds the guinness world record.
So why do we have teeth named after a dog? Actually, most mammals, particularly the predatory carnivores and omnivores, have canine teeth. These are the longer pointed teeth on the sides of the incisors and they have that name because they resemble and are in the same position as a dog’s long pointed canine teeth. They are also often called cuspids, dogteeth, or fangs.
Humans have four canine teeth, two on the upper jaw and two on the lower jaw on each side of the incisors. They usually erupt when a child is around 16 to 20 months, and the permanent replacements for the lower canines appear around the ninth or tenth year while the upper canines don’t usually appear until year eleven or twelve. The two canine teeth on the upper jaw may be referred to as eye teeth, because of their position directly beneath the eye. These pointy teeth have been made popular in vampire stories.
A canine tooth has one point called a cusp, which explains why they have also been given the name cuspid. Although our longest teeth, each has only one root but that root is thicker than an incisor’s root and grows deeply into the bone. These larger roots in the upper jaw support the upper lip, giving a pleasing roundness to its appearance.
Stronger than incisors, their main function is to bite and tear food, but they also have another important purpose. If you examine their position, you will see that the points of the lower canine teeth are closer to the middle line than the points of the upper canines. Being offset this way helps guide all the teeth into place when biting down. Good positioning of these teeth allows a smooth efficient bite. Poor positioning may lead to a less efficient bite, and your dentist may recommend treatment to improve their position. The shape and position of canine teeth are also are useful in forming words.
There are two problems common to permanent canine teeth. The first problem is when one becomes impacted. This just means that it gets stuck under the gum and does not erupt when it should. Sometimes the tooth breaks through later and the delay makes it come out in the wrong position, usually in front of or behind the other teeth. Braces can help align and make room for a canine tooth emerging in the wrong position, and the tooth will often align on its own if treated when it is first emerging. Waiting to fix this issue until the child is older may cause treatment to become much more difficult.
The second common problem for canine teeth is receding gums. Their position in the mouth makes them more vulnerable to aggressive tooth brushing, poor dental hygiene and smoking, which are common causes of this issue. Misaligned canine teeth may worsen this problem, which is another reason to fix their alignment when they grow in crooked.
Mammals can have four, eight, twelve or more incisors depending on their needs. Unlike incisors, canines generally only come in sets of four, unless the animal doesn’t need them, in which case they have zero. There are some exceptions where the animals of a species only have two canines on the upper or lower jaw, but four is the max. This makes sense, because they are usually so large that more would not fit easily into the mouth and would make hunting more difficult. Their size and position depend on what an animal needs them for.
As mentioned earlier, many animals have canine teeth. They are vital to predators, and are generally larger, longer and have more defined points than other teeth. Carnivores need them to hold and kill prey, and to bite or tear off food. Dogs and wolves obviously have canine teeth, since that is where the name comes from, but cats also have prominent canine teeth, and you can see just how large and pointed they are when a tiger roars. Canine teeth in an omnivore are very similar to those of a carnivore. They are long, pointed and used for the same functions.
Herbivores do not need such large and defined canine teeth. Many, such as rodents, do not have any. Other species do have them, but they closely resemble their incisors. Deer, sheep and cattle which all chew cud, usually only have two on the bottom jaw.
Interestingly, in many species the canine teeth are much larger in the males and can be up to 400% longer than those of the female of the species! A few species that display this trait are pigs, boar, musk-deer, seals, walruses and some species of apes such as the baboon and gorilla. Showing these larger canines helps a male to threaten rivals and predators.
There are many other strange examples of canine teeth in animals. The babirusa has four canine teeth that grow upward and curl back toward the head. They are used for fighting other males. If the babirusa doesn’t grind these fang-tusks down, they can grow into the head and kill the animal!
As you can see from the skull of a sabre tooth tiger, their upper canine teeth grew into two large fangs. Their lower canines sat closer to the front of the jaw and were just slightly larger than the incisors.
Imagine the frightening sight of a deer with fangs. That is exactly what you will see in a male musk deer during mating season! These unusual deer do not grow antlers and use fangs instead while battling other males. Just as other deer regrow their antlers every year, musk deer lose and regrow their fangs every year. Although the males have these long fangs, musk deer are herbivores and only use the fangs for fighting.
Unicorn horns are actually canine teeth which come from the sea creature called a narwhal. Although the narwhal has no other teeth, it does have two canine teeth sockets. Usually, only one tooth grows, and it forms the swordlike horn which extends through its upper lip. The horn forms in a spiral and can grow to over eight feet long! About one in 500 males will develop two tusks, and sometimes the second tusk grows to the same length as the first. While not as beautiful as the mythical unicorn, narwhals are still incredible creatures.
The hippopotamus has a strange looking set of teeth and the develops the longest canine teeth of any land animal. The lower canines grow up to 20 inches long with lower incisors that reach up to 16 inches. Their lower canines and incisors continually grow and are only used for fighting.
There are many more examples of amazing differences in canine teeth in the animal kingdom. Ours seem quite boring in comparison but are still vitally important for eating and speaking and need to be well cared for.
If this post was interesting stay tuned! In December’s blogs we will be discussing types of molars and unusual teeth situations in humans and animals. You can also read the last blog about Amazing Incisors and Their Many Shapes and Uses.
At Jungle Roots Children’s Dentistry & Orthodontics, we strive to provide the highest comprehensive pediatric and orthodontic dental care in a unique, fun-filled environment staffed by a team of caring, energetic professionals. We believe the establishment of a “dental home” at an early age is the key to a lifetime of positive visits to the dentist.