The formation of teeth, known as odontogenesis, begins at the level of the tooth germs inside the jaws (upper and lower). In the case of deciduous (milk) teeth, this process begins at embryonic level in the mother’s womb.

When the baby is born, most of the tooth germs already have their crowns developed, with only the root missing for the tooth to be complete. This demonstrates the link between a healthy pregnancy and well-developed teeth. The first milk tooth is born around 6 months of age, and the deciduous dentition is fully erupted by the age of 3.

It consists of a total of 20 teeth, 10 in the mandible and 10 in the maxilla. Chewing is one of the main stimuli for tooth eruption.

Around one year of age, the permanent teeth begin to erupt. However, their eruption normally only takes place from the age of 6 with the eruption of the first molar and permanent upper and lower incisors.

From this age onwards, deciduous teeth are gradually replaced by permanent ones. Around the age of 12 the 2nd molars erupt and between the ages of 17 and 21 the 3rd molars erupt, leaving the permanent dentition with 32 teeth (16 in each jaw).

What is the function of teeth?

The main function of teeth is logically to chew food. Teeth are classified according to their position and function. Thus, we have

• Incisors: teeth at the front of the mouth used for cutting food.
• Canines: have a pointed shape and are used to tear food.
• Premolars and molars: located at the back of the mouth and used to grind food.

However, in addition to their main function, teeth also help with phonetics and are crucial for facial aesthetics.

Why do we have two sets of teeth?

After eruption, the teeth stop growing. As milk teeth erupt at an infantile age, they have small dimensions adapted to the jaws that support them.

However, unlike the teeth, the jawbones continue to grow. As a result, these deciduous teeth need to be replaced with more mature ones, the size of which is better suited to the diameter of adult jaws.

Do wisdom teeth count towards a complete permanent dentition?

Wisdom teeth or third molars have a similar chewing function to the other molars. However, the lack of space for these teeth is becoming increasingly common.

This often leads to their partial eruption or lack of eruption, necessitating their surgical extraction. There are many theories that try to explain this phenomenon, caused by the shortening of the perimeter of the jaws and directly of the respective dental arches.

One of the most consensual explanations is due to the fact that diet has evolved over the years from harder raw foods to much softer cooked or processed foods, where such a large number of dental pieces no longer makes sense. As a result, it is now common to consider an adult to have complete dentition when 28 teeth are present.

What does third set of teeth mean?

Unlike other animals, such as sharks, which have several sets of teeth, humans still only have two sets of teeth. However, several advances in bioengineering using stem cells have already made it possible to regenerate new teeth in animals at laboratory level.

Until this technique has been developed enough to be safely used in humans, the fixed replacement of a lost tooth will continue to involve implantology.

Curiously, in the rehabilitation of the totally edentulous using implant-supported fixed prostheses, the fact that this solution is very similar in aesthetic and functional terms to the natural dentition means that patients sometimes refer to it as the 3rd dentition.