Why are premolars present in the permanent dentition

The molar - structure and function

The molar has many functions in the human dentition. It is part of an ingenious system that takes on a variety of functions when eating. Every single tooth has an individual structure and can be clearly distinguished from the others. We explain to you what a molar looks like and which functions it takes on.

Table of Contents

Which tooth is a molar?

Molars are also known as posterior teeth or molars.The molars include all teeth beyond the front and canines. In the deciduous dentition, there are 2 deciduous molars in each half of the jaw.

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In the permanent set of teeth, there are two smaller front molars, called premolars, in each half of the jaw. Behind it there are two, or if there are wisdom teeth, three, larger rear molars. These are called molars.

Molars - structure

In all mammals one can distinguish front teeth from molars. The technical term for the presence of different types of teeth is heterodontics. In contrast to this, reptiles have homodontic teeth.

In humans, the small front molars on the chewing surface of the tooth crown have two or three cusps that are separated from one another by furrows (the dentist calls them “fissures”). Most so-called premolars have one root, some (for example the anterior premolar in the upper jaw) have 2 roots.

The rear large molars are larger and have 4 or 5 cusps. The molars usually have three tooth roots, although anatomical deviations are sometimes possible.

Molars - breakthrough

The teeth go through two so-called dentitions. The second dentition follows the eruption of the milk teeth: permanent teeth replace the milk teeth.

  • The first molar usually erupts at the age of six, which is why it is called a six-year-old molar.
  • This is followed by the front teeth.
  • The first premolar breaks with the 10th-12th, the second then with the 11th-13th. Year through.
  • The second molar has its breakthrough with the 12th-14th Age.
  • The last molar tooth breaks through: with the 17th-30th Age. That is why it is called the wisdom tooth.

Basically, the teeth of the lower jaw are “one step ahead” of those of the upper jaw and appear a little earlier. When the permanent teeth get ready to erupt, they move closer and closer to the milk teeth. Their roots then continue to dissolve, which is why they ultimately fall out and make room for the permanent teeth.

In some people, the wisdom teeth, or certain front or molars, are absent. These are then not created and are also missing after the eruption of all permanent teeth in the row of teeth. On the other hand, in rare cases, there are excess teeth.

Molars - function

Incisors are designed in such a way that they are suitable for biting off food. Molars, on the other hand, have a wide chewing surface and can grind the food through their cusps and furrows.

For this it is important that the teeth are in contact with the opposing teeth in the other jaw and also with the neighboring teeth. The saliva and the complex movements of the jaws ultimately create a soft chyme.

In addition, they absorb the chewing force of the jaw and thereby protect the front teeth from overload. They are built in such a way that they can withstand great forces.

By chopping up food, they are an important part of digestion. In addition, the posterior teeth protect the temporomandibular joint from excessive stress.