Why Do Some People Not Have Wisdom Teeth?


Wisdom teeth can be described in many words, but the ones that come to my mind are; unpredictable, indecisive and expensive. 

These wise teeth aren’t that wise at all, coming in from all different angles, getting stuck in the weirdest positions and are potentially infection-causing. 

Because of these problems (and others that can be seen below) and becoming essentially useless teeth, our bodies have adapted over the years leaving us with fewer teeth. 

Evolution is the answer

Wisdom teeth usually provide little to no function nowadays. But if you go back a few 100,000 years they played a pretty important role. 

In the very very distant past, wisdom teeth helped our ancestors eat the food that we usually use a sharp knife and fork for.

Those rough and tough foods required a lot more force and function in order to break it down before digestion. As well, the wisdom teeth were needed to replace broken or lost teeth.

The teeth that take the most force in the mouth are your first molars (you get these workhorses when you’re around 6 years of age).

Because the first molars take the most force load and the way the jaw is slightly curved, your wisdom teeth are barely used. 

Even if they can be used, that’s only for the very small percentage of people who have had them fully erupt in the right direction. 

We aren’t cavemen anymore and with evolution, a few things have changed in our bodies over the years. 

But what exactly has changed? 

We as humans went through a very large evolution period where our brains actually became larger, making an issue of space in the jaw for those 3rd molars. 

This change in anatomy made our jawbones get smaller, leaving little room for your wisdom teeth. Consequently, now more people are missing wisdom teeth. 

If you are one of the lucky ones (or more evolved) you may be missing some or all 4 wisdom teeth, or if you are a bit behind the times like myself you have all 4! Thanks Mom and Dad!

Fun fact; we actually used to have another set of teeth behind the wisdom teeth, I even have a couple of patients who have an extra tooth, or on their x-ray, you can see that the wisdom teeth looks like another tooth is fused to it. It’s incredible to see this evolution first hand in my dental chair! 

What are wisdom teeth anyway?    

The wisdom teeth are circled in red.

Wisdom teeth are the 8th teeth back from the front of the mouth and usually erupt between the ages of 16 and 22. 

Sometimes they form fully partially or not at all. They provide little to no function, often causing more harm than good. 

How many teeth do adults have 

Adults have 32 teeth, 28 not including wisdom teeth. 

I’ve had only a couple of patients in all the years I have been practicing that have had extra teeth, and they have looked like tiny little pegs with not a lot of detail, more resembling a long blob and as mentioned above, they can even fuse to the teeth in front of it. 

Why they are called wisdom teeth

They get their name from the time period in which they usually erupt. The wisdom teeth usually erupt when we are more “wise” entering adulthood… although I know a few people would argue that we aren’t that wise at this age. 

Shape

Every tooth in your mouth has a certain anatomy. As an example; the front teeth always form the same way, with a genetic predisposition to be in the same shape. Yes, it can vary a little bit, but for the most part, they follow the same guideline. 

These rules don’t apply to the wisdom teeth. How rebellious! 

They can have some pretty interesting shapes, not conforming to one shape. This can make it even more difficult to clean. 

When us hygienists are cleaning your teeth we use a lot of imagination in the way of picturing what the tooth looks like underneath the gums. Don’t let that scare you, we are not going under the gums totally blind. 

We know the general anatomy of all the teeth, and we use our sense of touch to feel the tooth and exactly where our instrument is at all times. Remember when I mentioned that the shape of the wisdom teeth can vary… this is why it can even make it difficult for us to clean because we don’t know the exact shape the tooth is under the gums, any nooks and crannies or really curved roots. 

As well, the gum tissue comes up higher on the wisdom teeth, leaving a deeper than normal pocket to clean that can prevent some instruments that are too big from fitting in that tiny space. 

Again we can feel, but it can be difficult to get all the way to the back of your mouth. Those cheeky cheeks and tongues can get in our way. 

X-rays help us tremendously. We use them to see the angle of the tooth, and where the bone levels are around the teeth as well as any moderate to heavy build-up underneath the gums. I am always referring to x-rays while I am cleaning my patient’s teeth. 

Extractions

People can also not have wisdom teeth because they have already had them extracted. 

It’s a big topic when you turn 16; when are you getting your wisdom teeth out and what holiday or vacation time is it going to ruin. 

For me it was Christmas. I was devastated to miss out on my mom’s homecooked Christmas dinner (I got to have extra icecream instead so maybe I was the real winner). I barely got to enjoy my break from school as winter activities were off-limits and talking a lot proved to be difficult for a couple of days. 

Getting wisdom teeth extracted has such a bad reputation, mostly fueled by the notion to brag that you “made it through” and competition between friends for who had the worst experience.

Let me remind you, people aren’t really going to be jumping up and down to tell people how GREAT and AWESOME their wisdom teeth extractions went. So you’re really only going to hear the bad stories. 

These exclamations of extraction horror stories and funny videos on YouTube can make people fear dental work and can often make people want to skip out on the whole procedure altogether. 

This may come back to haunt them in the long run because the list of problems associated with keeping wisdom teeth is quite long. 

Issues with keeping wisdom teeth 

Because of this lack of space, problems associated with wisdom teeth can range from mild issues to major infections that could potentially prove to be fatal. Below you can find the most common. 

Shifting teeth

Erupting wisdom teeth can cause the teeth in front of them to shift forward. This can reverse expensive orthodontic treatment, causing crowding and crooked teeth. 

If you’ve worked so hard improving your smile, it’s really unfortunate when it regresses back to how the teeth were prior to orthodontic treatment. 

Crowded and crooked teeth can make it more difficult to clean parts of your mouth and can lead to gum disease and or excessive wear on the teeth. 

Gum disease

If the wisdom teeth cannot fully erupt through the gums, part of the tooth may be covered in the gum tissue (us dental people like to use fancy words and call it an operculum). 

A- Wisdom tooth
C- Operculum

Food and bacteria get stuck under this flap of tissue and to be quite honest, it’s impossible to keep completely clean. It can lead to bad breath, infection in the gum tissue and eventually the bone tissue supporting the teeth.

If this infection continues and not taken care of by either way of gum surgery to remove the operculum or extraction of the wisdom teeth, it can lead to periodontal disease (also known as gum disease). This disease will break down your gum and bone tissue, and it cannot be cured or rebuilt.  

Once you have periodontal disease you can never get rid of it, you can only control the amount of the bacteria causing the disease, which in turn will slow down the process of bone loss. More bacteria = more infection = more tissue loss. 

Periodontal disease can and will eventually spread to the other teeth in your mouth and can have effects on the body and has been proven to be linked with diabetes, rheumatoid arthritis, mental health, osteoporosis, pre-term labour, low birth weight, Alzheimer’s and some forms of cancers.

This study was published on the National Center of Biotechnology Information and it goes into depth about the connection between periodontal disease and associated systemic diseases.

In a lot of instances, the wisdom teeth can get “caught” underneath the gums and bone by the molars in front of them which means they are unable to erupt into the mouth. This happens often due to the direction and angle of the erupting wisdom teeth. This is called an impacted wisdom tooth. 

impacted wisdom tooth on the right

Cyst formation

All teeth form in sacs within the jaw bone, a protective “womb” like area. In some instances, the sac can fill with fluid and become an issue. When the sac fills with fluid and puts pressure on the tissues around it, that tissue can start to die or become damaged. 

The tissues that are at risk include the jaw bone, nerves and the teeth around it. 

Infections 

Infections can occur from impacted, partially and fully erupted wisdom teeth. It can happen slowly or come on suddenly. The symptoms of infection could include one, multiple or all of the following; swelling, pain, limited opening of your mouth, redness, pus, bad smell, bad taste in the mouth, and bleeding. 

If you think you may have an infection, seeing a dental professional right away is extremely important as dental infections can become extremely dangerous quickly.

If you don’t have access to a dentist, the emergency room may be where you need to go.

Remember how close it is to the brain, and in some cases, it could actually enter your bloodstream and infect your whole body and potentially become fatal. 

Nerve damage

On the lower jaw, the wisdom teeth roots can be in very close proximity to the nerve that runs through your lower jaw. If damaged it can leave permanent numbness around your lower jaw and cheeks and a partial section of your chin. 

We are especially concerned if we can see that the roots may overlap the nerve. Because of this, it is important to be assessed frequently to make sure you get them out at the most ideal time. 

If the wisdom teeth roots are this close, the oral surgeon may want you to have a 3D cone beam radiograph (a type of x-ray) taken. These 3D x-rays can be manipulated on the computer and cross-sections of the jaw can be observed.

This allows the oral surgeon to know EXACTLY where the nerve is in relation to your tooth. Sometimes the oral surgeon may leave a portion of the root in your jaw untouched because it’s proximity to the nerve. 

Decay

Because of the difficulty of cleaning, and the position in general, wisdom teeth are extremely susceptible to decay which can lead to infection.

As well, for a dentist to properly fill a tooth it needs to be kept dry. The chance of moisture contaminating the tooth during a filling is very high on wisdom teeth. It will cause the filling material to not adhere well to the tooth, causing it to fail. 

Decay present in the tooth at the back of the mouth

Depending on the angle of the tooth and the ability of the dentist to access it, an extraction might be necessary. And the longer you wait to have your wisdom teeth extracted, the roots and bone will be completely formed making for a potentially more difficult extraction with higher risks. 

Why wisdom teeth are so hard to keep clean. 

There is a natural curvature of your lower jaw (mandible). This curve goes upwards the farther back it goes. This causes the gum tissues to come up higher on the wisdom teeth vs the front teeth. 

As mentioned above, you may even have an operculum of tissue that extends onto the biting surface of the tooth that can trap food and bacteria underneath leading to a possible infection. 

The cheeks and tongue get in the way to, and sometimes they have a mind of their own. The cheeks and tongue muscles can contract without you even realizing it, pushing the toothbrush away from the gums. 

Having a smaller tool to help get in those small spaces may work better for you instead of a bulky toothbrush head.

I often recommend that my patients use a Sulcabrush to clean away the food and bacteria. The brush comes to a fine point and is angled in order to get the back of the teeth and clean it. 

Another winner is the Waterpik, it blasts water under the gums to rinse away the food and bacteria. The bacteria that cause the gum disease cannot live where there is oxygen, so by using the Waterpik, you create an environment under the gums where the bacteria cannot thrive and duplicate. 

This gives your body a chance to heal itself, improving the health of the tissues around the teeth and preventing gum disease. 

Maintain regular dental cleanings and check-ups

Having regular dental appointments can prevent, discover, and treat the issues associated with wisdom teeth. Maintaining your oral health will help maintain your overall body health. 

We take an x-ray to check for the wisdom teeth around the age of 15-16. This is the average age that you will need to be assessed. It is easier to extract the wisdom teeth when the roots have not fully formed and are not anchored in the jaw bone.

We usually refer to an oral surgeon because honestly, they do it day-in and day-out, having all of the necessary equipment. This can mean an easier recovery and less chance for complications. 

If the extractions are very straight forward and the teeth have erupted into the mouth, a regular dentist may take them out if they see it fit. 

We’ve covered a lot about wisdom teeth here, and I hope you have found at least one thing to be informative! 🙂

Are you more evolved? 

Holly Verran RDH

I am a Registered Dental Hygienist in Ontario, Canada. I hold registration and good standing with both the College of Dental Hygienists of Ontario and the Canadian Dental Hygiene Association.

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