Skip to Content

What’s the biggest tooth in your mouth?

The size of teeth in your mouth can vary greatly depending on factors like age and genetics. However, when it comes to the biggest tooth, there are a clear front runner. The largest teeth in the adult mouth are the molars, specifically the maxillary first molars. Let’s take a closer look at why these teeth take the prize for biggest, and what role they play in the mouth.

Anatomy of Molars

Molars are the large, square teeth at the back of the mouth used for grinding food. There are 12 molars total – 6 upper molars and 6 lower molars. The maxillary first molars are the 3rd tooth back from the midline on the upper arch. These are usually the first permanent molars to erupt.

Maxillary first molars are generally the biggest of all the molars. Their large size is necessary to handle their heavy biting forces used during chewing. These teeth have the following features:

  • 4-5 cusps for increased surface area for grinding food
  • Broad chewing surface to crush and grind food
  • Thick enamel to withstand heavy forces
  • Large, stabile roots to anchor the tooth

The biting surface of a maxillary first molar is about 30-35mm, compared to 20-25mm for lower molars. Their mesial-distal width is 10-11mm compared to 9-10mm for other molars. These dimensions make maxillary first molars the clear winner when it comes to size.

Role of Molars in the Mouth

Why are molars so big compared to other teeth? It comes down to their specialized function.

Chewing, also called mastication, is one of the most important roles of teeth. The molars at the back of the mouth are positioned to grind food into small particles that can be easily swallowed. Their size, shape and location are perfectly designed for this role.

Chewing with the molars breaks food into tiny pieces and increases the surface area for digestion. This allows the body to more efficiently extract nutrients and calories from food. Proper chewing is also beneficial for:

  • Stimulating saliva production
  • Preventing overeating by giving the brain time to receive satiety signals
  • Avoiding GI upset from swallowing large pieces of food

Since first molars are the first permanent teeth to erupt, around age 6, they play an especially important role in chewing and nutrition in childhood development. They also guide the proper placement of other teeth as the rest of the permanent teeth come in.

Molar Size Over Time

The size of molars changes over the course of a lifetime.

In childhood, the permanent first molars initially erupt at about a quarter to a third of their eventual full size. They continue growing and developing roots until around age 9-10.

As an adult, molars reach their maximum size and functionality. With proper oral hygiene, molars can remain strong and functional for decades.

However, as a person ages, several factors cause molars and other teeth to wear down and decrease in size:

  • Erosion from acidic foods and drinks
  • Grinding or bruxism
  • Gum recession exposing more tooth surface
  • Chipping or cracking

Worn molars can increase the risk of dental problems and impact nutrition. That’s why taking good care of your original adult molars can maintain chewing ability for a lifetime.

Biggest Tooth – Fun Facts

Here are some interesting trivia tidbits about the biggest tooth in your mouth – the first maxillary molar!

  • The longest human tooth on record was 1.26 inches long, over 3 times longer than average molars.
  • The heaviest human tooth weighed 0.2 ounces, equal to the weight of a small paperclip.
  • Human molars can bite with a force up to 55 pounds on a single tooth.
  • Your teeth are just as unique as your fingerprints. No two sets of teeth are alike.
  • Molars are the most likely tooth type to need a root canal procedure.
  • Around 5% of people have extra teeth beyond the normal 32.
  • The hardest substance in the human body is tooth enamel.
  • Contrary to popular belief, teeth themselves do not contain nerves and cannot feel pain.

Importance of Protecting Molars

Because first molars are so critical for chewing and nutrition, especially in childhood, it’s very important to take good care of them by:

  • Brushing 2x per day with fluoride toothpaste
  • Flossing daily
  • Eating a tooth-healthy diet low in sugary and acidic foods
  • Seeing a dentist for regular checkups and cleanings

If a molar becomes damaged, prompt dental treatment is key. Options may include crown placement, root canals, or tooth extraction and replacement with a dental implant. Paying attention to molar health can keep your biggest teeth functioning for decades.


The maxillary first molars take the prize for the biggest tooth in the average adult mouth. Their large size suits their important function – grinding food during chewing. But molars must be properly cared for due to their vulnerability to dental problems. Give your hardworking biggest teeth some TLC and they’ll serve you well for many years to come!