Teeth are essential. They help people talk, chew, and swallow food. Adults typically have 32 teeth, four of which are wisdom teeth.
One 2019 article states that a full set of adult teeth consists of 16 lower teeth and 16 upper teeth.
In this article, we will discuss the anatomy and function of teeth, how many teeth adults and children have, how to maintain healthy teeth, and when to see a dentist.
According to a 2019 article, a full set of adult teeth typically numbers 32, including four wisdom teeth.
Each row of teeth includes:
- four incisors, in the middle of the row at the front of the mouth
- two canine teeth, one on either side of the incisors
- two premolars and three molars at the back, with five on each side
However, not everyone has third molars, or wisdom teeth, in their jaw. If an adult has wisdom teeth, they tend to start to emerge when a person is around 18 years old. They may not emerge at all.
If a wisdom tooth does not emerge properly or becomes infected, a dentist may have to remove it.
Teeth start to develop before birth, and children tend to have all their baby teeth by the age of 3.
Each tooth consists of a crown and root.
The crown is the visible white part, and the root is the invisible part of the tooth hidden by the gums. The root anchors the tooth into the jawbone.
Teeth also consist of layers called enamel, dentin, cementum, and dental pulp.
Enamel covers the crown or the outside of the tooth and protects it from physical and chemical injuries.
According to a 2020 article on tooth development in American Physiological Reviews, enamel develops in three stages:
Ameloblasts, which are a type of cell that only occur in the teeth, make enamel.
Initially, these cells make enamel proteins and crystals. These proteins and crystals will eventually turn into enamel.
During this stage, around 25% of ameloblast cells die. Researchers believe this may be because they begin to contain too much calcium.
As a result, the ameloblasts produce fewer enamel proteins.
During the maturation stage, enamel crystals grow, which makes the enamel hard and durable.
Ameloblasts also change their appearance, turning into either ruffle-ended or smooth-ended cells.
These different shapes stop the movement of small molecules in the enamel, helping to protect the crown of the teeth.
Dentin forms the main part of dental tissues.
Dentin is a similar structure to bone. The cells that form dentin are odontoblast cells, similar to osteoblast cells in bone. Unlike bones, dentin does not have blood vessels.
Cementum is a tissue that covers the root’s surfaces.
There are different types of cementum. According to a 2016 article in the journal, Japanese Dental Science Review, acellular fiber cementum covers between 60–90% of single-root teeth and 33–50% of multi-root teeth.
Other types of cementum, such as cellular mixed stratified cementum (CMSC), cover other parts of the roots. CMSC covers roughly 66% of molar roots.
Cementum’s primary function is to support and fix the teeth in the jawbones.
The center of the tooth contains dental pulp, which consists of loose tissues, including nerves, blood vessels, and connective tissues.
The dental pulp attacks the bacteria with antibacterial, immune, and inflammatory responses. This may cause the body to reject and fight off the bacterial infection.
However, if this does not happen, the dental pulp may remain inflamed. This causes part of the pulp to die and can cause a root canal infection.
While teeth help people talk, their primary function is to chew.
The teeth cut and grind food into little chunks, which allows a person to swallow and digest it easily.
However, different kinds of teeth have different functions.
There are four types of teeth:
The incisors are what some people call the ‘front teeth.’
Adults typically have eight of these, with four along the top row and four along the bottom row.
Incisors cut food up into smaller pieces, which the teeth and tongue then move to the back of the mouth.
The canine teeth are the teeth that are slightly more pointed than the others. Some people may call these ‘fang teeth.’
As well as cutting up and tearing food, these teeth make sure that the upper and lower rows of teeth do not clash.
The shape of the canines allows them to guide the rows of teeth so that they smoothly slide off each other when the jaw moves.
Most adults have eight premolars.
These are the larger teeth that sit behind the canines. Humans have four along the top gums, and four along the bottom, two on each side.
The primary function of premolars is to begin grinding up the food.
There are three types of molars:
- first molars
- second molars
- third molars, or wisdom teeth
These sit toward the back of the mouth, and most adults typically have eight molars, with a first and second molar on each side of the mouth.
Third molars, or wisdom teeth, sit right at the back of the mouth. Some people do not develop wisdom teeth.
The function of the molars is to grind up the food into smaller pieces to help people swallow easily.
However, wisdom teeth do not typically have a function.
If adults have their wisdom teeth, they will have 12 molars.
The first set teeth, or baby teeth, begin to emerge when an infant is about 5 months old, and they will typically have their first full set by the age of 3.
A full set of baby teeth consists of 20 teeth. Each row of 10 includes:
- four incisors
- two canines
- four molars
Baby teeth do not include premolars. When a child reaches about 6 years old, their baby teeth will start to fall out, and adult teeth will replace them.
To help maintain a healthy mouth, the best way to take care of teeth is by brushing and flossing regularly.
- placing the toothbrush at a 45-degree angle so that it touches the gums and teeth
- paying particular attention to the gums and the molars
- brushing for at least 2 minutes
- use 16–18 inches of floss and wrap it around the fingers
- gently thread the floss between the teeth until it meets the gums and move it up and down
- use a clean section of floss every two teeth
When people first start to floss, they may notice that their gums bleed.
This is not uncommon and should stop when the gums become healthy after regular cleaning and flossing.
If the bleeding continues, see a dentist.
People should make regular appointments with a dentist.
A dentist will decide how often a person needs a check-up, according to their oral health.
A person should see a dentist if they experience any unusual symptoms, such as ulcers, infection, inflammation, or bleeding.
Some oral health problems that need a dentist’s attention are:
Teeth are essential, as they help people chew, swallow, and talk.
Each tooth contains several structures that maintain oral health.
People must brush and floss regularly to keep their teeth and mouth healthy.