In animal anatomy, the mouth, or oral cavity, is the opening through which vertebrate animals feed and make sounds to communicate with each other.. Inside, we find a series of structures essential to understanding the ability to nourish ourselves, such as the tongue, saliva, salivary glands, palate and teeth.
For example, saliva, besides softening the food bolus and favoring chewing, also presents lysozymes that destroy the bacteria present in the food, thus protecting our intestinal tract from possible infections. The teeth, on the other hand, also have a clear phonatory function beyond chewing, since pronunciation and tone are obtained, to a large extent, by the placement and health of the dental apparatus.
With all this data, we can see that the oral structures have many more functions than it might seem at first. Stay with us, because today we will tell you all about the 6 types of teeth and their characteristics, highlighting some of their functions that you probably didn’t know about..
How are teeth classified?
As you may already know the main function of the teeth is chewing.. Thanks to them, we can cut, mix and break up the food we eat, a process that allows the tongue and larynx to form a bolus that is easily swallowed. These mineralized tissue structures begin to form from the embryonic stage and begin to erupt in the first months of life, marking the transition from a liquid diet to an eminently solid one.
When talking about types of teeth, we can resort to the typical classification (incisors, canines, premolars and molars). We will deal with all these concepts in future lines, but first we would like to make an essential distinction with regard to the dental apparatus.
1. Types of teeth according to their permanence
We begin by analyzing the dental typology according to their permanence throughout the life of the individual, in other words, we differentiate between deciduous and permanent dentition. Let’s get down to it.
1.1 Deciduous or “milk” teeth
Deciduous teeth are those that emerge from our mouth from the first stages of life, generally from the sixth month of age. The first to erupt are usually the incisors (6 months), while the second molars appear at 33 months, completing deciduous tooth development at approximately 3 years of age.
These teeth, much more fragile and smaller in number (there are only 20 in total, compared to the 32 permanent teeth), accompany the infant until 7 years of age. accompany the infant until the age of 7 years in the case of the incisors, a period that extends to 10-12 years in the case of the second molars.. They are much smaller and less resistant, since the dentin and enamel layers are thin. By the onset of puberty, complete tooth replacement has already taken place.
1.2 Permanent teeth
The permanent teeth, as their name suggests, are those that will be with us for the rest of our lives. They are composed of a very hard outer enamel layer (made of hydroxyapatite, the hardest mineral tissue in the world), a thick bed of dentin, root cementum, dental pulp and periodontium. They are extremely resilient structures, as they withstand the mechanical stress of chewing for 70 years or more..
2. Types of teeth according to their location
Once we have turned our attention to the definitive dentition, it should be noted that it is composed of 32 teeth, 16 in the upper jaw and 16 in the lower jaw, which are distributed as follows: (4 incisors + 2 canines + 4 premolars + 6 molars) x 2 = 32 total teeth..
The function of these teeth is mainly masticatory, but they also play an essential role in voice emission, esthetics and individual hygiene and the preservation of the mandibular arch, that is, the shape of the mandible and its relationship with the rest of the face. Below, we present each of the types of permanent teeth according to their location.
The 8 anterior teeth in the lower and upper jaw (4 + 4) are called incisors. are called incisors, a term that clearly refers to their potential for cutting and breaking up food, but without grinding it. The incisors that are presented frontally are the central incisors, while the adjacent incisors are called lateral incisors.
These dental appliances have a single root and a sharp incisal edge. If we quantify the total functionality of each tooth with a maximum value of 100%, we can say that the masticatory function of the incisors is only 10%, but that they have phonatory and esthetic functions in 90% of their spectrum. The lack of incisors completely disintegrates the facial structure of the sufferer, so they are considered a very important esthetic component in today’s society.
After the first 4 incisors (central and lateral) we find the canines, one on each side of the dental arch, making a total of 4 (2 in the lower jaw and 2 in the upper jaw). The canines are considered the cornerstone of this arch, as together with the first molars, they are believed to be the most important teeth for chewing.
These teeth are triangular in shape (with a single cusp and root) and their main function is to tear the teeth. and their main function is to tear food.. They are extremely important for jaw dynamics and the sliding of teeth over each other in masticatory movements and, for this reason, they have the deepest root and the most anchored to the bone of all the dental apparatus. Its function is 20% chewing and 80% phonetic/aesthetic.
There are a total of 8, 2 on each side of the dental arch, both above and below. They are located adjacent to the canines, with 3-4 cusps and 1-2 tooth roots. The premolars do not exist in the primary dentition, which is why the number of teeth in infants is so small. They are the first in the list in charge of assisting and performing the crushing, or in other words, the disintegration of food into very small pieces that will form the digestible bolus.
Of their total functionality the premolars have 60% of chewing work and 40% of phonatory/esthetic work.. They are hardly seen in normal situations and are not in contact with the tip of the tongue, so most of their functionality is eminently mechanical.
There are a total of 12, 6 above and 6 below, 3 on each side of the dental arch, so they represent the bulk of the total dental structures. They are the ones with the flattest surface, about 4-5 cusps and 2 roots. Their function is to grind the food, so they must have a large and wide shape to allow this mechanical movement of the teeth. that allows them to perform this mechanical movement in the most effective way possible.
Curiously, there is a growing tendency in the population not to develop the third and last molars, also known as “wisdom teeth”. This phenomenon is known as agenesis, and approximately 20-30% of people in the world are missing some of their third molars.
The absence of third molars is a clear example of the vestigial mechanisms that occur in living beings. It is believed that our ancestors developed third molars to break up foliage and plant matter more correctly, thus “compensating” in some way for the difficulty our species has in digesting cellulose. Faced with a mostly herbivorous and frugivorous diet, the molars make their way ahead of the incisors and canines.
Today, these molars have become completely useless and in many cases are even harmful, as they can cause pressure and discomfort.They can cause pressure and misalignment of adjacent teeth due to their large size and uneven growth. Interestingly, it has been detected that their development is completely linked to heredity: the expression of the PAX9 gene is responsible for the lack of the third molar.
As you have seen, the world of teeth goes far beyond chewing. Beyond cutting up food, these hard elements are essential for maintaining the shape of the mouth, tone, vocalization and various aesthetic attributes. Thanks to them, we are able to ingest the food that gives us life and communicate with each other, no more and no less.and communicate with each other, no more and no less.