Teeth – Everything you want to know about teeth
Teeth are one of the most precious part of our body. They only erupt in two sets for any person in it’s whole life. Once they are gone, Teeth never comes back. These are made up of the hardest substance in our body called as Enamel. These are essential for cutting, tearing, grinding and chewing the food.
Food habits are very different across the species living in this world. It also affects the shapes of teeth. How? We will learn about it but firstly, let’s discuss the basics of teeth.
What is Tooth or Teeth?
Teeth are the hardest structure found in the body. They are made up of 4 important parts Enamel, Dentin, Cementum, Pulp. The primary function of teeth is to chew our food and convert it into a bolus. In digestion, Bolus is a word used for food chewed and mixed with saliva.
Teeth is the plural form of tooth. Multiple tooth are together called as Teeth,
What is a Dentition?
Dentition is a word used for a set of teeth. Humans have two dentitions in their lifetime which are Primary dentition & Permanent Dentition.
Primary Dentition
This set of teeth is seen in children upto the age of 13 years. The primary dentition has 20 teeth which consists eight Incisors, four Canines, Eight Molars. This set doesn’t have premolars. The teeth are smaller and whiter than permanent teeth. The refractive index of primary teeth is similar to milk, thus the teeth are also known as milk teeth.
Permanent Dentition
The set of teeth which comes after the primary dentition is called permanent dentition. This is the last set of teeth and if they shed then no teeth will erupt in their place.
The permanent dentition consists Eight Incisors, Four Canines, Eight Premolars, Twelve Molars. The total number of teeth in it are 32.
What are the 4 types of teeth?
In humans, Teeth are of four types which are stated below:
- Incisors – Incisors are the teeth in the front which are used to cut the food. The incisors are of two types – Central Incisors & Lateral Incisors. The middle teeth is the central incisor while the tooth just lateral to it is the lateral incisor. There are eight incisors in both primary & permanent dentition, four in the upper jaw and four in the lower jaw. The have a sharp and straight edge like a knife.
- Canines – The tooth just lateral to the lateral incisor is the canine tooth. Canines are also known as Cuspids. Canines are used to tear the food. This tooth is mostly seen in carnivorous animals, They use it to tear the flesh. Humans have 4 canines in total, two in each jaw. The have a sharp and pointed edge.
- Premolars – Primary teeth don’t have premolars but they are present in permanent teeth. There are total eight premolars in permanent teeth, four in each jaw. The teeth just beside the canine are the premolars. There are 2 types of premolars i.e. First Premolar & Second Premolar. Premolars are also called as Bicuspids because they have two sharp and pointed edges.
- Molars – Molars are the last teeth behind the second premolars, They are used for grinding and chewing the food. There are eight molars in primary dentition(Four in each jaw) while twelve molars in permanent dentition(six In each jaw). There are three molars in permanent dentition i.e. First Molar, Second Molar & Third molar. The third molars are missing in the primary dentition.
Parts of Teeth
A tooth can be divided into two parts:
- Crown – The crown is the upper portion of tooth. It is white in color and is made up of enamel, Dentin & Pulp.
- Root – Root is the lower portion of tooth which can’t be seen on clinical examination. It is made up of Cementum & Pulp.
Enamel
Enamel is the outer covering of the crown portion of the tooth. It is made of hard calcified tissue i.e. Hydroxyapatite Crystals. Enamel is non-living tissue and has no defense mechanism of it’s own. It is the only portion of tooth which needs extensive care through brushing, cleaning & flossing.
Enamel is also the hardest substance found in human body.
Dentin
Dentin is just beneath the enamel or cementum, it is seen as the second covering which protects the pulp canal. The dentin is a living tissue.
Composition of Dentin:
- Hydroxyapatite Crystals – 45%
- Organic Material – 33%
- Water – 22%
The junction between the enamel & dentin is known as the dentino-enamel junction.
Cementum
Cementum is the calcified avascular mesenchymal tissue which forms the outer covering of the root of teeth. It is mainly of two types:
- Cellular Cementum
- Acellular Cementum
Composition of Cementum
- 45% Inorganic
- 35% Organic
- 20% Water
Pulp
It is the only vital part of teeth. The pulp contains all the nerves and vasculature which helps the tooth in getting sensations and blood supply.
Pulp is found in the innermost portion of tooth. It can be divided in 3 parts:
- Pulp Chamber
- Pulp canal
- Pulpal horns
Conclusion
Teeth are an important part of the body and helps in various masticatory functions. Absence of teeth affect the body adversely as people who don’t have teeth to chew are at greater risk of being malnourished. Since, They are unable to chew most of the food and they usually avoid them.
We should take proper care of them. We will discuss about maintaining proper hygiene of teeth later and update this post regarding it. Hope you like this post, please drop a comment below if you have any query regarding it.
