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What Are Molars & What Is Their Function?

Molars are the teeth in the back of your mouth with loads of grooves and divots. Learn what they do and how to fix any issues with them.

Last updated on

October 30, 2024

Katharine Hall

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What Are Molars & What Is Their Function?

While you might just refer to your teeth as “teeth,” there are actually different names and functions for the types of teeth in your mouth. And those chompers at the back of your mouth are some of the most unique.

Those large teeth at the back of your gums are called molars, and they have a distinct function that would make it difficult to live without. Here’s everything you need to know about molars, as well as the different types of teeth in your mouth.

What Are Molars?

Molars are the flat teeth at the back of your mouth that have a few cusps, or divots, on the top. They are used exclusively for grinding and crushing food as you eat so that you can easily swallow and digest.

Humans have six upper molars and six lower molars, totaling twelve in all. The first set of these usually erupts through the gumline at age six. The next poke through at age 12, and the final set pokes through between the ages of 17 and 25.

This final set of molars is referred to as wisdom teeth. For some people, these erupt normally, and you’re able to live with them your whole life. However, some people need to get them extracted because there is not enough space in the jaw to support them. If you don’t get your wisdom teeth extracted, it can lead to impacted teeth and gums.

Other Types of Teeth

Your molars are just one of many different kinds of teeth in your mouth. Together, they all work together to let you eat, speak, and function normally.

Here are the other types of teeth that make up the 32 total in your mouth:

Incisors

Your incisors are at the front of your mouth, and these can be seen when you smile. Each person has eight total, with four on the top and four on the bottom. While incisors serve an important role in the overall appearance of your mouth, their main functions are to bite into food and help you pronounce words properly.

Shaped like chisels, these sets of teeth have sharp edges that help you bite and tear apart food when you sink your teeth into something. These are usually the first teeth to erupt, appearing at just about six months old.

Canines

Canines (or cuspids) are the sharper teeth on the sides of the incisors that look like pointy daggers. They also help you bite and tear food.

Additionally, canine teeth have the added responsibility of guiding the mouth closed when the upper and lower jaws come together. Without these permanent teeth, it would be much more difficult to eat foods like meats and fruits.

Your canines usually come in at around age nine on the lower part of the jaw and age 11 or 12 on the upper jaw. You have four total: two on top and two on the bottom.

Premolars

Premolars, also known as bicuspids, sit between the canines and the molars at the back of your mouth. You have four premolars on the top and four on the bottom.

Premolars have a flat surface with ridges used for crushing and grinding food to make it easier to swallow. They also help keep the shape of the face. If you lose your premolars, it can start to make the skin outside of the jawbone sag inward.

Wisdom Teeth

Wisdom teeth are a type of molar, but they are usually considered a completely different type of tooth because they function slightly differently than a regular molar. This is because many people do not have the space in their mouth to properly fit wisdom teeth when they grow in, which can cause them to become impacted. Often called the third molar, these are the last teeth to pop up — usually at age 17 to 21. 

Many dental health professionals consider wisdom teeth to be vestigial, which means they served a purpose at one point but don’t anymore. Our ancestral diets used to consist of a lot of tough plants, hard nuts, and meats that required large wisdom teeth in order to grind and chew through. But since modern food is prepared differently, we don’t actually need them to grind food quite as much.

As our bodies went through small evolutionary changes, this included a smaller jaw, which makes it hard for wisdom teeth to grow properly for most people. Bear in mind, however, that some people’s wisdom teeth grow perfectly fine.

Molars and Cavities

Molars are the most cavity-prone teeth in your mouth because of the grooves, crevices, and divots on the top of these teeth. Food and sugars can easily get stuck in these crevices, which can sometimes be hard to remove.

When these particles stay on the tooth’s surface for a long period of time, it creates a sticky film called plaque. Plaque can then harden into tartar, which creates a shield for underlying bacteria to eat away at these starches and sugars.

The acids in plaque erode the outer minerals of human teeth called the enamel (the hardest substance in the body). This causes tiny holes or openings that are the first stages of cavities. Once the enamel wears away, it can start to protrude towards underlying layers like cementum, dentin, and pulp, which is when you might be at risk for infection.

Pulp is filled with blood vessels and nerves that can make you feel swollen and irritated by bacteria. Since there is no place for pulp to expand inside the tooth, this can make your molars feel super painful as the nerves become pressed.

This is why it is vital to practice proper oral hygiene. When brushing your teeth, spend a little extra time in the back teeth with your toothbrush to help get food out of the pits and grooves on your tooth’s surface. Additionally, be sure to floss to remove food particles from in between the teeth as well. Both baby teeth and adult teeth require dental care and constant monitoring. 

How To Fix Cavities on Molars

Depending on the extent of the tooth decay on the molars, there are a few options to remedy them. 

Filling

A dental filling is usually the first line of defense to fix a minor cavity. This can be done during the first stages of a cavity that has not yet progressed to the pulp of the molar.

With a dental filling, the infected material of the tooth is drilled away by a dentist. Then, the area is cleaned before an amalgam material is used to fill in the hole. The filling is then bonded to the tooth with a blue light so that the material mends itself to the tooth.

Fillings restore the structure and function of your tooth, and they look just like the color of your natural teeth. Fillings are painless and quick procedures that can be done in your dentist’s office within just a few minutes. There is also no recovery time, meaning that you can eat, drink, brush, and floss as normal afterward.

Root Canal

If your cavity gets into the root of the tooth, that infected pulp needs to be removed through a process called a root canal. With a root canal, the infected pulp is removed from the inside of the tooth, and the hole is disinfected. From there, a filling is used to fill the hole and restore its function.

In most cases, a root canal is covered with a dental crown, which is sort of like a tiny cap that goes over your teeth. This helps protect the underlying tooth and makes the filling last longer without coming out.

Root canals are also a painless procedure because you are given a local anesthetic ahead of time. Root canals are done on the same day. Mild discomfort might be present for a few days, but you can go back to normal habits once the local anesthetic wears off.

Extraction

If tooth decay becomes severe, you might not be able to retain your natural tooth at all. In this instance, you might need to get your molar extracted. Extraction removes your tooth from the root and leaves a gap. With that said, dental implants or bridges can be used to restore the structure and function of your molars.

Wisdom tooth extraction can differ if the teeth are removed before they erupt through the gumline. With this type of extraction, incisions are made in the gum tissue to expose the teeth. The tooth is then divided into sections to make it easier to remove before the gums are then stitched shut to promote healing.

If a wisdom tooth has already grown above the gumline, then a typical extraction can take place without the need to cut into the gum tissue.

The Cost of Cavity Corrections

Getting cavities corrected is a common dental procedure; considering that cavities are some of the most common diseases in the entire world, it’s easy to get them fixed. However, they come at a cost.

If you need to get a root canal to fix your cavity, that can run you upwards of $2,000 without insurance. And even with insurance, the cost of annual premiums and fees might not even make it worth it in the first place.

Other Reasons for Molar Pain

Cavities and tooth decay are some of the major reasons for tooth pain in the molars, but there are some other reasons why you might be feeling dull pain in that portion of your mouth.

For one, it might be gingivitis. Gingivitis is also known as gum disease, and it occurs when your gums are not cleaned properly and become inflamed. This oral health condition can affect the nerves of your teeth, which make your molars feel painful.

It could also be a fracture, which can happen to your molars if you bite down on something hard. If a crack extends to the pulp or root of your tooth, it can cause pain in the same way as tooth decay.

Oddly enough, sinusitis can also be the root cause of pain in your teeth. Sinusitis, or a sinus infection, affects the cavities in your skull, known as your sinuses. These cavities run along the upper part of your jaw, and when they become inflamed, they can place pressure on the teeth in the back of the mouth in the upper jaw, leading to a toothache.

Sources:

Wisdom tooth extraction | Mayo Clinic

Wisdom Teeth: Function, Location & Anatomy | Cleveland Clinic

What is a Root Canal? | American Association of Endodontists

Sinus infection and toothache: Any connection? | Mayo Clinic

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