Types of Teeth

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.

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.

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.

Adult Teeth

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.

Permanent 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.

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.

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.