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Types of teeth classification are categorized as Incisors, Canines, Premolars, and Molars. Food is sliced by the incisors, torn by the canines, and crushed by the molars and premolars. Gums protect the roots of teeth, which are implanted in the maxilla (upper jaw) or mandible (lower jaw).
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Keyterms: Teeth, Incisors, Canines, Premolars, Molars, Gums, Maxilla, Mandible, Primary teeth, Baby teeth, Milk teeth
Human Teeth Introduction and Diagram
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Teeth are made up of different tissues with different hardness and density. Humans, like the majority of animals, are diphyodont, which means they have two sets of teeth. The initial set of teeth, often known as "primary teeth," "baby teeth," or "milk teeth," usually consists of 20 teeth.
Human Teeth
Dental Formula
The number of each type of tooth in a particular species is indicated by dental formulas.
The jaw is symmetrical on both sides. Thus, the dental formulas only consider the half jaw when calculating the number. The fraction's numerator is the number of teeth in the upper jaw, while the denominator is the number of teeth in the lower jaw. In the following sequence (left to right), the formula reflects the number of teeth: Molars, Incisors, Canine, Premolars
Example: lower/upper = ICPM/ICPM
Dental Formula
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Types of Teeth in Humans
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Between the age of 17 and 25, most humans have 4 teeth called the wisdom teeth. These grow at the back of the mouth to complete the adult set of 32 teeth. These 32 sets are further divided into 4 different types: 8 incisors, 4 canines (cuspids), 8 premolars (bicuspids), 12 molars including 4 wisdom teeth.
Read on to know about the Types of Teeth in Humans:
Incisors
Incisors grow in the front part of the mouth. These teeth have razor-sharp edges and they can chop food into little, digestible chunks. There are eight incisors in the human mouth, four in the upper jaw and four in the lower jaw.
Central Incisor Diagram
Canines
Cuspids are another name for canines. They are located at the dental arches' 'corners.' Their sharp, elongated, and pointed surface distinguishes them. Their main job is to grab and tear food (tough food such as meat). Two canines are located in the upper jaw and two are located in the lower jaw.
Canines in Humans
Premolars
Premolars, also known as premolar teeth or bicuspids, are teeth between the canine and molar teeth. The permanent set of teeth in humans has two premolars each quadrant, for a total of eight premolars in the mouth.
There are at least two cusps on them. During chewing, or mastication, premolars are also called transitional teeth. Food can be moved from the canines to the premolars and then to the molars for grinding, rather than straight from the canines to the molars. The reason being, they have characteristics of both the canines and the molars.
Premolars in Humans
Molars
The molars, also known as molar teeth, are a set of big, flat teeth located in the rear of the mouth. In animals, they are more developed. They're generally used to crush food during chewing.
Tooth Section of a Molar
Wisdom Teeth
Wisdom teeth or ‘the third set of molars’ are the vestigial and final set of molars. This set of teeth grows around the age of 18 to 25. Most people get their wisdom teeth removed mainly because of the poor alignment and partial eruption. The onset of wisdom teeth often leads to bacterial infectious diseases, pain, swelling and stiffness of the jaw.
Parts of Human Tooth
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Teeth are the most abrasive materials in the human body. Teeth, in addition to being necessary for eating, play a crucial part in speaking. The following are examples of tooth parts:
- Enamel is the toughest, white exterior layer of a tooth. Calcium phosphate, a rock-hard mineral, is used to make enamel
- Dentin is the layer beneath the enamel. It's a rigid tissue with tiny tubes inside. Heat or cold can enter the tooth through these pathways when the enamel is broken, causing sensitivity or pain.
- Pulp is the tooth's softer, living inner component. The pulp of the tooth contains blood vessels and nerves.
- Cementum is a connective tissue layer that secures the teeth's roots to the gums and jawbone.
- Periodontal ligament is the tissue that aids in securing the teeth to the jaw.
Parts of Human Tooth
Formation of Dental Lamina
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Primitive oral cavity or stomodeum is lined by 25 squamous epithelium. This is termed as the Oral Ectoderm. Ectoderm contacts the endoderm with a membrane called the Bucco pharyngeal membrane.
At 27 days of pregnancy, the Bucco pharyngeal membrane ruptures and the oral ectoderm comes in contact with the endoderm. Considering the ectoderm of humans, beneath the ectoderm, there is a connective tissue.
Formation of Dental Lamina
Most of the connective tissues are Ectomesenchyme. These enable the ectoderm to start the tooth development. This development takes place in the anterior portion of the maxilla, i.e. future maxilla, and the future mandible as they are still not developed.
Certain parts of the basal cell proliferate more rapidly compared to the other areas and they form a primary epithelial band. Eventually, this band gets divided into 2 parts, once will be lingual and the other will be the buckle.
The epithelial band will divide into the inner lingual process and the outer buckle process. The inner lingual process is called the Dental Lamina and the outer buckle process is called the Vestibular Lamina.
The vestibular lamina forms the vestibule of the mouth. When the tongue is placed between the cheeks and teeth, the space formed there is called the vestibule. The dental lamina forms the ectodermal portion of deciduous teeth.
The complete activity of dental lamina extends for a period of 5 years. The dental lamina is still active in the third molar region after it has disintegrated elsewhere.
Dental Lamina Diagram
What are Diphyodont and Polyphyodont?
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Any animal with two sets of teeth, the "deciduous" set first and then the "permanent" set, is called a diphyodont. Most animals are diphyodont, which means they have a robust, durable, and full set of teeth to chew their food.
Polyphyodont, on the other hand, has teeth that are continually replaced. Monophyodont are creatures with just one set of teeth that do not change over time. Diphyodont, on the other hand, have two sets of teeth that do not change over time. Any animal whose teeth are constantly replaced is known as a polyphyodont.
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Things to Remember
- Teeth begin to grow around the 11th week of foetal development, despite the fact that newborns are born with no visible teeth. Your 20 primary teeth, as well as the 32 permanent teeth you will eventually acquire, are already there in your mouth at birth, according to Colgate.
- The enamel on your teeth is the toughest material in your body. According to the Mayo Clinic, broken enamel cannot regenerate or mend on its own. However, toothpaste, mouthwash, and calcium rich meals can help to build and protect your enamel.
- There are two sets of teeth: milk teeth and permanent teeth. Milk teeth form throughout infancy and fall out between the ages of six and eight years.
- Permanent teeth are the second set of teeth that replace milk teeth and last for the rest of our lives. They deteriorate as people age.
- Teeth are important in the digestion and absorption of food. Humans consume food throughout their lives. As a result, teeth must be extremely strong and securely fixed in order to endure years of chewing.
Previous Year Questions
- If for some reason the parietal cells of the gut epithelium become partially non-functional, what is likely to happen?... [NEET 2010]
- Jaundice is a disorder of... [NEET 2010]
- Duodenum has characteristic Brunner's gland which secrete two hormones called...[NEET 2004]
- A healthy person eats the following diet-5 gm raw sugar,. 4 gm albumin, 10 gm pure buffalo ghee adultrated with 2 gm vegetable ghee (hydrogenated vegetable oil) and 5 gm lignin. How many calories he is likely to get?...[NEET 2013]
- A person who is eating boiled potato, his food contains the component...[NEET 2000]
- Anxiety and eating spicy food together in an otherwise normal human, may lead to...[NEET 2012]
- Calcium deficiency in the body occurs in the absence of...[NEET 1994]
- Choose the correct enzyme - substrate pair... [NEET 1996]
- Continuous bleeding from an injured part of body is due to deficiency of...[NEET 2002]
- Duct leading from parotid gland and opening into vestibule is...[NEET 1998]
- During prolonged fastings, in what sequence are the following organic compounds used up by the body...[NEET 2003]
- Emulsification of fat is carried out by...[NEET 1990]
- The characteristic that is shared by urea... [KCET 2009]
- The primary dentition in humans differs from... [NEET 2015]
- Stool of a person contain whitish grey colour due to... [NEET 2002]
- Food is moved along the alimentary canal by the contraction known as... [JIPMER 2003]
- A baby boy aged two years is admitted to play school and passes through a dental check - up. The dentist observed that the boy had twenty teeth. Which teeth were absent?… [NEET 2017]
- Which cells of "Crypts of Lieberkuhn" secrete antibacterial lysozyme?... [NEET 2017]
- Secretin and cholecystokinin are digestive hormones. They are secreted in….[NEET 2005]
- Which of the following statements is not correct?... [NEET 2015]
Sample Questions
Ques. Which of the following functions as a cutting aid in human teeth? (1 Mark)
Ans. The incisors are the front four teeth in each arch, and their purpose is to cut food with their razor thin edges.
Ques. What is the average number of teeth in a human? (1 Mark)
Ans. Humans are diphyodont, which means we have two sets of teeth throughout our lives: milk teeth and permanent teeth. As children get older, their 20 milk teeth are eventually replaced by 32 permanent teeth.
Ques. Which teeth of humans are shovel-shaped and used for nibbling, cutting, and tearing? (1 Mark)
Ans. Canine teeth are utilised for ripping food, whereas central incisors and lateral incisors are used for biting and cutting. Chewing and grinding are done with the premolars, molars, and wisdom teeth.
Ques. What keeps teeth in place? (2 Marks)
Ans. Two of your skull's bones serve as anchors for your teeth. The upper teeth are housed in the maxilla, a bone that makes up the upper jaw. The mandible (jawbone) is the bone in which your lower teeth are housed.
Your jaw is made up of two bones: the mandible and maxilla. On the right and left sides of your head, they are linked. Your jawbone is the most powerful and the only one in your skull that can move. When you bite and chew your meal, this comes in useful.
Ques. Name the different types of teeth. What is the function of each type? (3 Marks)
Ans. The different types of teeth are:
- The teeth in the front of the mouth are known as incisors. Each jaw contains four incisors. Biting and cutting food is done with them.
- The incisors are situated adjacent to the canines. In each jaw, there are two canines. They are used to pierce and rip food.
- Premolars are located close to canines. Each jaw has four premolars. They help you chew and ground your food.
- At the end of the jaw, the molars are located adjacent to the premolars. Each jaw contains six molars. They can also be used to chew and grind food.
Ques. What is Your Tooth’s Crown? (3 Marks)
Ans. Teeth can be compared to icebergs. The iceberg looks like a tiny ice lump floating in the ocean. When, in reality, it's more like an ice mountain rising from the sea. It's the same with your teeth. They can be found both above and below the gum line. The crown is the gleaming, white part of your mouth that you can see when you open your lips.
Food, drink, and saliva all come into touch with this portion of the tooth. It is the tooth's strong covering that protects it. As a result, the crown of a tooth is protected by enamel, a strong material. A layer of hard tissue called dentin lies beneath the enamel.
Ques. Why Do Teeth Come in Different Shapes? (3 Marks)
Ans. When you look at your grin, you'll see that your teeth aren't all the same. Your teeth, in fact, come in a variety of shapes and sizes.
While no two teeth in your mouth are alike, their overall form may be used to classify them. Eight incisors, four canines, eight premolars, and twelve molars make up an adult set of teeth.
Your incisors start in the centre and branch out to the left and right. These massive front teeth are razor-sharp. The canine teeth are located next to the incisors. They have a cusp, which is a distinguishing feature. They look like a dog's pointy teeth.
The premolars are the teeth after the molars. These teeth are known as bicuspids because they have two cusps.
Ques. What do the different kinds of teeth do? (3 Marks)
Ans. Each tooth has a unique structure that allows it to perform a specific job when chewing.
Incisors are useful for cutting up and retaining food portions, such as when biting into an apple. Your incisors can also aid in the perception of food texture.
Your meal is ripped into smaller, more manageable bits by canine teeth. Eat a piece of thick protein, such as grilled chicken, to get your canines to work.
The premolars are shaped like canines and molars. Premolars, like canine teeth, aid in the cutting and tearing of food.
Molars are a type of grinder that is used to grind food. Food is transported further back into your mouth when you chew, where it is crushed up by your molars. Molar
Ques. What are Cavities? (3 Marks)
Ans. Cavities are small holes in the enamel and dentin layers of teeth, as their name indicates. Cavities are caused by dental decay, which occurs when germs infiltrate damaged or fractured teeth.
Cavities are caused mostly by simple sugars. Foods like soda, juice, candy, and other sweets can stick on your teeth for a long time. These simple carbohydrates can be converted into acids by bacteria in your mouth, eroding the enamel of your teeth. As a result, a cavity develops.
On your own, you could detect that you have a cavity. When a cavity develops, many patients feel pain and discomfort. When you consume anything sweet, your teeth may be more sensitive to temperature or discomfort.
Ques. What are Wisdom Teeth? (4 Marks)
Ans. Your wisdom teeth, also known as third molars, are four in number. They have the same structure as molars and perform the same functions when chewing. Wisdom teeth, on the other hand, may need to be extracted in some cases.
Wisdom teeth usually appear in your late teens or early twenties. The last of your permanent teeth to emerge is this one (another word for your teeth coming in). When wisdom teeth erupt, they might push on neighbouring teeth, resulting in crowding and pain. They can even cause your other teeth to become misaligned.
Wisdom teeth are typically surgically removed if your dentist feels they will create problems. This treatment is generally performed before the eruption of the teeth. When wisdom teeth are removed, the number of permanent teeth in your mouth decreases from 32 to 28. Don't worry, you'll manage without your wisdom teeth just fine. You could even feel better at ease.
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