Life of Teeth
Children
INFANTS AND CHILDREN
The first set of teeth we have as children are called milk or deciduous teeth. People also sometimes refer to them as ‘baby teeth’ because they are smaller than adults’ teeth and start coming through when we are babies.
Between the ages of 6 and 13 years, all the milk (deciduous) teeth are lost and replaced with new, bigger adult teeth. As the new adult teeth grow up into the mouth, they push on the milk ones and make them wobbly until they eventually fall out.
By the time most people are teenagers, they should have 28 adult teeth although some of these may still be coming through. This is also the age when braces are provided if teeth need to be straightened. The only teeth left to come through after this are the wisdom teeth. Wisdom teeth usually erupt in late teens.
Click through the next few pages to find out more about milk and adult teeth.
MILK TEETH
Milk (deciduous) teeth start coming through when babies are between 5 and 8 months old. They are smaller than adults’ teeth because children’s jaws are smaller. As the jaws grow, more teeth come through. There are 20 deciduous teeth altogether, and they finish coming through by about age 2 to 2½ years.
Look at the model. It shows all the milk (deciduous) teeth. Explore the model with your mouse to find out the names of the teeth. A description of the teeth is below.
Deciduous incisors: These are the front teeth, and there are 8 of them altogether (four at the top and four at the bottom). They are usually the first teeth to come through between age 5 and 8 months, and are good for cutting into food (for example biting into an apple). You can tell the which are the incisors by the flat biting edge and because they only have one root.
Deciduous canines: These front teeth are also known as ‘eye teeth’, and are more pointed in shape than the incisors. There are four altogether and they come through at around age 16 to 23 months, and like the incisors they each have a single root. In animals, such as dogs, the canines are much longer, and are used for tearing off chunks of food. In humans, they are smaller in size, and are good for cutting into food similar to incisors.
Deciduous molars: These are the larger back teeth, which are good for crushing food into smaller pieces before being swallowed. This is known as chewing. It is easy to tell which are the molars because they look bigger than the front teeth, and have ‘bumpy’ or irregular surfaces for chewing with. They also have more than one root, and the roots are quite splayed. There are 8 molars altogether which come through between the ages of 1 to 2½. Later on, these teeth are replaced by premolars in adults.
28 ADULT TEETH
Adult (permanent) teeth start coming through at around age 6. They are larger than milk teeth. As the jaw grows, there is more room for the new adult teeth to come through (erupt). There are 32 adult teeth altogether but sometimes the wisdom teeth have trouble coming through if the jaw isn’t big enough. Keep reading to find out more about adult teeth. Click on the teens section to find out about wisdom teeth.
Permanent incisors: These are the front teeth, and there are 8 of them altogether (four at the top and four at the bottom). They are usually the first permanent teeth to come through, and are good for cutting into food (for example biting into an apple). You can tell which are the incisors by the flat biting edge and because they only have one root.
Permanent canines: These front teeth are also known as ‘eye teeth’, and are more pointed in shape than the incisors, but like the incisors they each have a single root. There are 4 altogether, and in animals such as dogs and cats the canines are much longer, and are used for tearing off chunks of food. In humans they are smaller in size, and are good for cutting into food similar to incisors.
Premolars: These are the new, adult back teeth which replace the first and second deciduous molars. There are eight premolars altogether. The four first premolars erupt first followed by the four second premolars. The milk (deciduous) teeth don’t have premolars as back teeth, just molars.
Permanent molars: These are the larger back teeth, which are good for crushing food into smaller pieces before being swallowed. This is known as chewing. Molars usually have more than one root each, and have irregular, or ‘bumpy’ surfaces with grooves called ‘fissures’. There are first, second and third permanent molars, which come through in that order.
First permanent molars: The four first permanent molars are similar in size to the second molars and come through at around age 6 to 8 years.
Second permanent molars: The four second permanent molars are similar in size to the first permanent molars and come through at around age 12 years.
Teens
By the time most people are teenagers, they should have 28 adult teeth although some of these may still be coming through (erupting). The final four adult teeth (wisdom or third permanent molars) don’t erupt until late teens – that is if they come through at all.
Early teens is when most braces are fitted if the teeth need to be straightened. For more information about braces, have a look in the treatments section on fixed and removable braces.
WISDOM TEETH
Wisdom teeth (or third permanent molars as they are known) usually start coming through in late teens. Sometimes there isn’t enough room for them to erupt properly and they get stuck (impacted), often against the tooth in front. Sometimes the tooth in front can become damaged, or the gums around the wisdom tooth can become infected and quite painful. That is the time to see the dentist and decide on the appropriate treatment.
The picture shows an xray of an impacted wisdom tooth (the tooth on the right) growing in the direction of the second permanent molar (tooth on the left). To find out more about wisdom teeth, visit our Smile website.
Adults
Looking after your teeth and gums is vital for a healthy mouth no matter what your age.
More people are keeping their teeth for longer mainly due to an improvement in the use of fluoride toothpaste and regular toothbrushing.
It is important to keep up a good oral hygiene regime. Brush your teeth twice a day with fluoride toothpaste, visit the dentist regularly and try not to consume too many sugary foods or drinks, especially between meals.
If you have several fillings (restorations), you may want to take a look at the sections of the site on treatments and conditions to find out more.
32 ADULT TEETH
The final four adult teeth should come through during late teens totalling 32 adult teeth. The descriptions below explain the functions of each of the teeth. To view a model showing all the milk and adult teeth erupting, take a look at the timeline showing the lifetime of teeth.
Permanent incisors: These are the front teeth, and there are 8 of them altogether (four at the top and four at the bottom). They are usually the first permanent teeth to come through, and are good for cutting into food (for example biting into an apple). You can tell which are the incisors by their flat edge at the top, and because they each have only one root.
Permanent canines: These front teeth are also known as ‘eye teeth’, and are more pointed in shape than the incisors, but like the incisors they each have a single root. There are 4 altogether, and in animals such as dogs and cats the canines are much longer, and are used for tearing off chunks of food. In humans they are smaller in size, and are good for cutting into food similar to incisors.
Premolars: These are the new, adult back teeth which replace the first and second deciduous molars. There are eight altogether, four first premolars and four second ones. Deciduous teeth don’t have premolars as back teeth, just molars.
Permanent molars: These are the larger back teeth, which are good for crushing food into smaller pieces before being swallowed. This is known as chewing. Molars usually have more than one root each, and have irregular, or ‘bumpy’ surfaces with grooves called ‘fissures’. There are first, second and third permanent molars, which come through in that order.
First permanent molars: The four first permanent molars are similar in size to the second molars and come through at around age 6 to 8 years.
Second permanent molars: The four second permanent molars are similar in size to the first permanent molars and come through at around age 12 years.
Third permanent molars: These are the very last of the adult teeth to appear between age 18 and 21 years, and are also called ‘wisdom teeth‘. There are four, and they come through at the very back and sometimes cause problems if there isn’t enough room for them.
DISSECTED TOOTH
This is what a tooth would look like on the inside, if it was sliced down the middle. Click on any part of the tooth to find out what it is called, and look below to find out what it does.
- Enamel
This is the very hard outer layer of a tooth, and is what you see covering teeth when you look in your mouth. It is smooth, and shiny and is the hardest substance in the body so is good for chewing food. It gives teeth their whitish colour, and is 1-2 mm thick. - Dentine
This is a hard, thick layer, just underneath the enamel, which forms the bulk of the tooth. It has lots of tiny tubes in it which contain nerves, which means teeth can feel the difference between hot and cold food or drinks. - Pulp
This is the middle part of the tooth, and is also the living part. It is a space inside the tooth where the nerves and blood vessels are found (which feel the difference between hot and cold). Blood pumps through tiny blood vessels inside the pulp, which help to keep the tooth healthy. - Root Tip
This is the very end of the root, and is where the blood vessels and nerves come into the pulp from the surrounding bone. This is the last part of a growing tooth to form. It is also where infection can build up when a tooth is very damaged, and this is called an abscess. - Fissure
Fissures are v-shaped grooves in patterns on the biting surface of back teeth which help us to chew our food. Have a look in your mouth and count how many of your bottom teeth have fissures. - Bone
The roots of teeth lie in the jawbone and are attached to the bone by fibres in the periodontal ligament. - Periodontal Ligament
This holds the tooth firm in the jaw bone, and is made of lots of tiny threads (fibres). These fibres attach the root of the tooth to the bone around it (socket). This is the part of the tooth that gets damaged in gum disease. - Gums
The gums are the soft tissues covering the bone around teeth. Healthy gums are firm and pink, but unhealthy gums can look red, and puffy, and can bleed when you brush your teeth.
50+
Teeth should last a lifetime if you look after them properly and visit the dentist regularly.
Click here to find out more about looking after your mouth.
Click here to find out what happens when you visit the dentist for a check up.
People over 50 generally need their mouths maintaining on a regular basis. Any fillings, crowns and bridges, or false teeth that have been provided in the past do still need checking from time to time. They might need repairing, or new ones made.
Problems with teeth and gums are usually easier to treat if caught early, and you are more likely to keep your teeth for longer. Healthy mouths are important for speaking as well as enjoying your food.
Click here to find out more about healthy eating.
Keep reading to find out more about what you might see in an older person’s mouth.
Tooth decay:
The crowns of teeth continue to decay if not looked after, so regular visits to the dentist are important at any age.
Also, receding gums gradually expose the roots of teeth, and these can decay too. Roots are softer than the crowns of teeth, and holes form quicker (dentists call this type of decay root caries). Holes in roots can be filled in the same way as holes in the crowns (or, the top parts) of teeth.
Gums (gum disease):
The effects of gum disease tend to get worse as people get older, so visits to the dentist to check gum health, and have your teeth cleaned professionally are important.
Older people tend to have more gum recession, which is what happens if you have gum disease over many years. This is why older people are sometimes called long in the tooth.
The lining of the mouth (soft tissues):
The skin inside the mouth, for example on the lips, insides of the cheeks, the palate (roof of the mouth), on the tongue and down the throat and needs checking from time to time to make sure it is healthy. Regular examinations can help dentists to spot problems early.
It has been found that mouth cancer is more common in people over 40 years, especially if they smoke, or if they drink excessively, but younger people can get it too. Did you know that around half of the 4,000 people diagnosed with mouth cancer every year in the UK die of it because it is discovered too late?
Click here for more information on mouth cancer.
The effects of tooth loss:
When teeth have been lost, they usually leave gaps in the mouth which can make eating difficult and affect your appearance. As more and more teeth are lost, eating and speaking becomes more difficult, and people sometimes experience discomfort around the jaw joints.
Dentures are false teeth which are fixed onto a plate and can be removed from the mouth for cleaning. You can have as many teeth as you like on a denture, ranging from one tooth to a full set. Dentures are often just made out of plastic, but some have metal parts that don’t usually show, to make them stronger and less likely to move about.
Click here for more information on dentures.
Bridges are false teeth which are permanently fixed in the mouth. They are anchored in place by being attached to one or more natural teeth either side of the gap usually. Materials used to make bridges include metal and porcelain. Porcelain can be made to look like natural teeth, and colours added when it is fired so that it matches your own tooth colour. Not all gaps are suitable for bridges, as it often depends on how healthy the remaining natural teeth are, and how many there are left.
Click here for more information on bridges.
Implants are another way of replacing missing teeth. It involves surgery to place a type of screw in the jaw, and then a crown is attached on top which is the part you can see. Implants are fixed in place permanently, and must be kept clean in the same way as natural teeth. Sometimes, removable dentures (or false teeth) are made to fit over implants, so that the dentures are removed for cleaning, but the implants stay in the mouth.
Click here for more information on implants.
