Teeth are a central component of the human dentition and play an important role in chewing, biting, and grinding food. Human teeth consist of several layers, including enamel, dentin, and the inner pulp. Enamel is considered the hardest substance in the body and protects the tooth from external influences.
In the dentition, incisors, canines, and molars work together to efficiently break down and grind food. The anatomy of a tooth includes the visible crown, the neck of the tooth, and the root embedded in the jawbone. In humans, a set of primary teeth (baby teeth) develops first, which is later replaced by permanent teeth. A healthy set of teeth is important for oral health, digestion, and overall well-being.
Teeth and the Dentition
Like many other vertebrates, humans have true teeth. These are hard structures located in the oral cavity that are used to break down food. What is unique, however, is that in humans, teeth play a major role not only in eating but also in communication. For example, teeth are frequently used in speech production, particularly in the formation of “s” sounds.
Biology generally distinguishes between true and false teeth. This distinction is based on the tooth’s composition. While true teeth consist of several hard substances such as enamel, dentin, and cementum, false teeth are structures made of horn. For this reason, human teeth are also referred to as “dentin teeth.”
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Types of Teeth
Teeth are classified into different categories based on their function on the one hand and the time of their development on the other.
Classification by Tooth Function
Each tooth in the human dentition fulfills a specific function and is anatomically adapted to it. Therefore, a distinction is made between:
- Incisors
- Canines
- Premolars
- Molars
The incisors are located directly at the front of the dentition. Their function is to cut food, thereby making it possible to bite off a piece. For this reason, the incisors are very sharp. Together with the canines, they form the front teeth of the human mouth.
The canines are significantly longer than all other teeth and have a conical shape. They are located directly between the incisors and the premolars. Their name refers to the characteristic bend in the human dentition at this point, which creates the impression of a corner. Their main function is to hold food in place, thereby enabling the front teeth to cut it.
The premolar is also known as the anterior molar. It has two to three cusps and partially breaks down the food that is ingested. During the primary dentition stage, the premolars perform the entire chewing function.
In adults, the so-called molars also develop. These serve exclusively to grind food. In this way, the teeth prepare ingested food for subsequent digestion in the stomach and intestines.
Classification by Time of Development
A person’s so-called baby teeth begin to grow during the first few years of life. These constitute a temporary set of teeth that is completely replaced during adolescence.
For most people, the first permanent teeth erupt between the ages of nine and eleven. Unlike the dull-colored baby teeth, these have a strong, white color.
In addition, some people begin to develop what are known as wisdom teeth starting at age 17. These can differ significantly in structure from the other teeth. Although they should generally have four cusps, some people have three or five. The number of roots also varies greatly. Furthermore, in some cases, they are fused together or even curved like a hook. While a complete human set of teeth always has a maximum of four wisdom teeth, additional teeth sometimes grow behind them. However, this occurs only very rarely. Only 0.001% of all people have a set of teeth with eight wisdom teeth.
Structure of the Teeth
The human tooth consists of three main parts:
- Tooth crown
- Tooth neck
- Tooth root
The tooth is composed of different layers. However, to the naked eye, only the enamel is visible on a healthy tooth.
Enamel is the hardest substance found naturally in the human body. This protective layer is formed by cells called ameloblasts and consists almost entirely of hydroxyapatite. This crystalline material is composed of calcium and phosphate. Enamel surrounds the entire tooth, thereby protecting it from external environmental influences.
Directly beneath it lies the dentin. This is the main material that makes up a human tooth. In addition to calcium and phosphate, it also contains a high proportion of protein and water, which is why it is significantly softer. It is also sensitive to pain and is quickly irritated by both cold and heat.
All stimuli are transmitted to the central nervous system via the nerves located in the pulp. The pulp surrounds the root segments and also contains numerous blood vessels. In this way, it nourishes the entire tooth and supplies it with nutrients. The root segments, on the other hand, anchor the tooth in the jaw and ensure a firm hold. They are surrounded by a thick layer of gum tissue.
Dental Diseases
Numerous diseases affect both the gum tissue surrounding the root segments and the tooth itself. In most cases, these manifest as severe pain and reduced ability to chew.
In humans, the following diseases and conditions requiring treatment are the most common:
- Abscesses
- Chronic bad breath
- Gingivitis (gum inflammation) and other gum diseases
- Tooth decay
- Periodontitis
- Teeth grinding (bruxism)
- Misaligned teeth.
Abscesses in the gums usually lead to a high fever and uncomfortable swelling. A severe infection causes intense pain and loss of appetite. These localized pockets of pus are usually caused by persistent inflammation of the tooth root. In some cases, however, they also occur when the first wisdom teeth erupt.
Unpleasant bad breath can result from numerous conditions. While the cause of short-term bad breath usually lies in the esophagus or stomach, chronic bad breath is caused by dental disease. A medical evaluation is recommended if these symptoms persist.
Tooth decay is the most common dental disease. In this process, acids produced by the bacterial breakdown of sugar progressively erode the tooth enamel. As a result, the tooth loses its natural protection and becomes susceptible to further damage. However, regular brushing and avoiding sugary foods can completely prevent this disease from occurring.
How are dental diseases treated?
Dentists have several treatment methods at their disposal. In cases of advanced tooth decay, fluoride treatment is usually used. In addition, many dentists also rely on dental sealants or remove the affected teeth entirely. If only a few areas are affected, the dentist drills them out with special tools and then fills them with one of many possible dental fillings.
Rare cases of tooth nerve inflammation, however, require comprehensive root canal treatment. During this procedure, the dentist exposes the tooth root and kills all bacteria using a laser. Finally, the dentist fills the resulting cavity with a filling.
