Parts of the tooth: all 7 parts explained!

Table of Contents

Before visiting your dentist for an appointment and performing any dental procedure, you might want to know about different parts of the tooth and the role each of them plays in oral and dental functions. Knowing tooth anatomy helps you better understand what you are going to face and how to discuss your concerns with your dentist in a more cooperative way. In this article, we are going to talk about what are the 3 main parts of a tooth, their anatomy, and how aging affects the tooth structure and anatomy.

Let’s dive deep into each one of them!

What are the 3 main parts of a tooth?

Each tooth is made of 3 main parts: crown, root, and neck. No matter the position of the tooth in the dental arch, or the upper or lower jaw, all teeth have these 3 main parts. These sections are the same in the milk teeth and the adult teeth. Now let’s talk about them.

The main part of the tooth 1: Crown

The crown is part of the tooth that is seen. This part is above the gum line. This facet of the tooth faces the oral cavity.

What is the role of the tooth crown?

The crown is the top part of the tooth and is responsible for talking, chewing, and biting. The role of the crown in a beautiful smile is undeniable. The shape of the crown varies based on the type of tooth and according to their surface shape, different types of teeth have different functions. 4 types of teeth are:

Incisors: Also called the cutting teeth, incisors are the central front teeth that are flat and broad with a sharp and thin edge. These features give them a chisel-like shape. These teeth are to bite the food and cut them into small chewable pieces. Incisors also play the most important part in having a beautiful smile as they are broad and are completely displayed while smiling. Your two upper central incisors contribute to pronouncing words, especially consonants.

Canines: Also known as cuspids. They are the longest teeth. Canine teeth have sharp and pointy ends that are used to grip and tear apart foods. They support the lips’ structures, as well as help with the chewing process.

Premolars: Premolar teeth are also referred to as bicuspids. They have a flat surface with ridges. Their main function is chewing the food. They crush, tear, and grind the food before sending them to the molar teeth. They sit between the canine and molar teeth

Molars: Molars are the biggest and strongest types of teeth with a large surface. They are used to grind up the food, breaking them into smaller particles, easy to swallow. They include the 4 wisdom teeth.

The main part of the tooth 2: Root

The root of the tooth is below the gum line and helps the tooth to stay in its place. This part is located in the jawbone, on both jaws. The number of teeth roots varies between different kinds of teeth. Usually, the number of roots for incisors, canines, and premolars is one. Molar teeth have two to three tooth roots.

What is the role of tooth roots?

The tooth root is responsible for keeping the tooth in its place in the bone. This root is also the part responsible for withstanding force bite and pressure. The root is also essential for maintaining jawbone integrity and preventing them from shrinking.

The main part of the tooth 3: Neck

The neck is the part of the tooth where the crown and root meet. Another term for the tooth neck is the dental cervix.

What is the role of tooth neck?

The neck forms a line between two layers of the tooth. The dental cervix can be considered a landmark in tooth anatomy where two different parts of the tooth, as well as two different tooth layers, meet. In addition to that, the neck is where the gum tissue, or gingiva, attaches to the tooth.

What are the other parts of the tooth?

Additional to the 3 main parts of the tooth, there are other parts. These parts are layers of different materials and substances that form the final structure of a tooth. If we need to separate them as parts, these layers are:

  • Part #1: Enamel
  • Part #2: Dentin
  • Part #3: Pulp
  • Part #4: Cementum

Now, let’s talk about them!

Part #1: Enamel

Enamel is the outermost layer of the tooth that covers the dental crown. Enamel is the hardest material in the human body and is formed of hard materials and minerals. The enamel does not contain any living tissue and can not grow back. When the enamel is shaved during a cosmetic dental procedure, the protective layer is gone and the tooth is sensitive and susceptible to injury. That’s why the teeth surface is covered after the enamel filing. The long and the short of it, without the enamel, a tooth is way too sensitive and defenseless.

Part #2: Dentin

Dentin is located under the enamel. The dentin is softer than the enamel but harder than bone as It is mostly made of mineral components. Dentin has a yellowish shade and makes up most of the teeth’ structure. Unlike enamel, dentin has the ability to grow back and regenerate in response to many tooth-damaging conditions such as tooth decay.

Part #3: Pulp

Under the dentin, there’s the pulp cavity that includes the dental pulp and the root canals.

The dental pulp is the layer In the center of the pulp chamber. This soft tissue is the innermost layer among all the layers and includes blood vessels, nerves, lymph nodes, and cells. As a result, the pulp is the living part of the tooth.

Root canals are the passageways for the nerves and vessels to leave or enter the pulp cavity.

Part #4: Cementum

The cementum covers the root of the tooth, just like the enamel covers the crown. The cementum is as hard as the bone. This layer binds the root to the gums and jawbones through some structures called periodontal ligaments.

Does tooth anatomy differ by aging?

Throughout the lifetime, the structure of the tooth changes. During different stages of life, the number of teeth alters, as well as the tooth texture. Let’s see how tooth anatomy differs by age.

Children’s teeth anatomy

Teeth in early ages of life are also known as baby teeth, temporary teeth, primary teeth, deciduous teeth, or milk teeth. They all indicate the fact that these sets of teeth are not to last for the rest of their life. The first teeth start to erupt at an average of 6 months old, followed by the eruption of other primary teeth until 33 months old. Primary dentition consists of 20 teeth, 10 teeth on each dental arch. This is because the mouth isn’t grown and big enough to place all the adult teeth in itself.

On the other hand, the anatomy of baby teeth is similar to that of adult teeth. They have the same part and layers. Differences are mostly in the thickness of tooth layers. Dental enamel in temporary teeth is thinner than the secondary dentition. Even though primary teeth will eventually fall out, Maintaining oral hygiene is crucial in children. In the case of cavities, the nerve tissue can be damaged which requires treatments such as a root canal. Nerve damage doesn’t go away by the eruption of the new set of teeth.

Adult teeth anatomy

Usually, at 6 years old, the first permanent teeth start to come out. In some people, it can start as early as 5 years old. On their way out, the permanent teeth push the temporary ones out, as the crowns start to erupt from within the gums, below the primary teeth. This results in the primary teeth resolving from within and seeming hollow as they fall out. Adults have 32 teeth in their mouths, as followed:

  • 8 Incisor teeth
  • 4 canine teeth
  • 8 premolar teeth
  • 12 molar teeth

The 4 wisdom teeth are parts of the molar teeth and are the last ones to erupt into the oral cavity. By the age of 12, all teeth should be permanent except the only ones that haven’t been erupted, the wisdom teeth. Also called the third molars, wisdom teeth start to come out at the age of 17 or 18.

These teeth should finish their eruption and be completely out by the age of 25. If deemed necessary, your dentist might recommend the surgical removal of your wisdom teeth.

Elders’ teeth anatomy

As a person ages, the structures of the tooth gradually change. The yellow layer of dentin becomes thicker. On the other hand, enamel which is a translucent layer becomes thinner. These two simultaneous alterations result in the teeth looking more yellow. Teeth also change in regard to height due to biting forces. The number of teeth remains the same until the end of life unless they fall off because of poor oral hygiene or tooth extraction done by the dentist.

References:

-Wiśniewska, Kamila et al. “Review on the Lymphatic Vessels in the Dental Pulp.” Biology vol. 10,12 1257. 2 Dec. 2021, doi:10.3390/biology10121257 Link

-Kunin, Anatoly A et al. “Age-related differences of tootth enamel morphochemistry in health and dental caries.” The EPMA journal vol. 6,1 3. 29 Jan. 2015, doi:10.1186/s13167-014-0025-8

-Ketterl, W. “Age-induced changes in the teeth and their attachment apparatus.” International dental journal vol. 33,3 (1983): 262-71.

-Maeda Hidefumi, Aging and Senescence of Dental Pulp and Hard Tissues of the Toth, Frontiers in Cell and Developmental Biology, 2020, DOI=10.3389/fcell.2020.605996

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