What are Incisors Teeth?
The incisors are a set of chisel-shaped teeth located on the anterior part of the oral cavity. The term incisors were derived from the Latin word ‘incidere’, which means ‘to cut’. A basic understanding of human teeth not only includes the anatomy but also the alignment and positions of each type of tooth. In the case of humans, a deciduous set of teeth falls off, and a new permanent set of teeth replaces the primary set of teeth. The primary or milk teeth are found in children. However, mainly there are four types of teeth: canines, incisors, premolars, and molars.
Here, we will learn about the incisor teeth functions, anatomy, and types.
Incisor Teeth Anatomy
The incisor teeth share a general tooth structure and anatomy. It will be easier to understand once you see the incisor teeth diagram. The incisor teeth are eight in number. All of them have a prominent crown and root. The crown is encased in an enamel covering, and the root is covered by cementum. The dentine, which covers the body of the incisor teeth, surrounds a central pulp cavity. This cavity extends into a pulp chamber that continues to the root canal.
A healthy adult has a set of 32 teeth,16 on each dental arch. The 8 incisors are located on either side of the midline of the dental arch. The incisors are located on the premaxilla and the mandible. This will be easier to picture once you see the incisor teeth diagram. Based on this, the incisors are classified into maxillary or mandibular incisors. Sometimes incisors are also classified based on their positions to the midline of the dental arch. The ones which are close to the midline are known as central incisor teeth. Whereas the ones away from the midline are known as lateral incisors.
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Types of Incisor Teeth
As stated above, based on their location, incisors are classified into various types. In this section, we will discuss the types of incisors. Maxillary central incisor teeth(2) are located on the upper jaw and are closest to the center of the lips to the midline of the dental arch. The maxillary lateral incisors(2) are also located on the premaxilla. However, they are situated laterally farther from the midline.
The lower jaw or the mandible also has two pairs of incisors, namely- mandibular central incisor and mandibular lateral incisors. The mandibular central incisor teeth(2) are located on the lower jaw and situated close to the center of the midline. Similarly, the mandibular lateral incisors are situated laterally far from the midline of the dental arch.
Based on the incisor teeth shape, the maxillary central incisors are larger than the lateral ones in both permanent and deciduous sets of teeth. However, this is vice-versa in the case of the mandibular incisors. There is also a significant difference in the length of the root of the central and lateral incisors in the case of permanent and deciduous dentition.
Incisor Teeth Functions
The main function of the incisor teeth is cutting or shearing food. The incisor teeth shape and anatomy describe their function. This shearing or cutting action is enhanced further due to the location of the incisor teeth. The incisors form the most anterior set of teeth. During the occlusion of the mouth, the sharp incisal edges help in the shearing of the food. So the incisors tear down the food into smaller pieces which later helps in the mastication of the food by the premolars and molars. Apart from humans, various other animals also have some similar kinds of uses for their incisor teeth. In rodents, the incisors grow throughout their lifetime, so they have to wear them out by gnawing. The upper elephant incisor teeth are modified into long and curved tusks. In carnivores, the incisors are used to tear and grip the meat. This is all about the incisor teeth function.
Interesting Facts about Incisor Teeth
Did you know the pulp chamber of the maxillary lateral incisors is rounder than that of the maxillary lateral ones. They also have two pulp horns?
Did you know the pulp chamber of the mandibular lateral incisor points initially has a wide labiolingual axis and three pulp horns?
Did you know the enamel on the topmost surface of your tooth is the hardest component of your whole body?
Did you know two people can never have an identical set of teeth, your teeth are as novel as your fingerprint?
Did you know tusks are an elephant incisor teeth utilized for digging for food and water, defence, and bearing and lifting?
Did you know besides incisors teeth, an elephant has four molars (six throughout the life of African ones) wherein one can weigh more than eight lb and grow 10-12 inches long?
FAQs on Incisors Teeth
1. What are incisor teeth and where are they located in the mouth?
Incisors are the eight teeth located at the very front of the mouth. You have four incisors on the upper jaw and four on the lower jaw. Their name comes from the Latin word 'incidere', which means 'to cut'. These teeth are characterised by their flat, chisel-like shape, making them perfectly adapted for biting into and cutting food.
2. What are the primary functions of incisor teeth in humans?
The main functions of incisor teeth include:
- Cutting Food: Their primary role is to take the initial bite and cut food into smaller, manageable pieces before it is passed to the canines and molars for tearing and grinding.
- Supporting Facial Structure: Incisors help support the lips and contribute to the overall facial appearance and smile.
- Assisting in Speech: They play a crucial role in the articulation of certain sounds, such as those for the letters 't', 'th', and 'd', by interacting with the tongue.
3. How do incisors differ from other types of teeth like canines and molars?
The four types of teeth in humans are specialised for different tasks. Here’s how incisors compare to others:
- Incisors: Have a thin, flat, chisel-like edge designed for cutting. They are not built for grinding or tearing.
- Canines: These are the pointed teeth next to the incisors. Their sharp, conical shape is designed for gripping and tearing food, particularly tougher items like meat.
- Premolars and Molars: Located at the back of the mouth, these teeth have broad, flat surfaces with ridges. Their primary function is to crush and grind food into a paste, preparing it for swallowing.
4. When do human incisors typically erupt?
Humans have two sets of incisors. The eruption timeline is generally as follows:
- Primary (Milk) Incisors: The first teeth to appear in babies, usually starting with the lower central incisors around 6 to 10 months of age. The upper central incisors follow shortly after.
- Permanent Incisors: These replace the primary teeth. The process begins around age 6 to 7 years for the central incisors and around 7 to 8 years for the lateral incisors.
5. Why are incisors more prone to chipping and what does this reveal about their structure?
Incisors are more susceptible to chipping or fracture compared to molars because of their structure and function. Their thin, blade-like design is optimised for slicing and cutting with minimal force. This specialisation means they lack the bulk and broad, reinforced surfaces of molars, which are built to withstand the immense pressure required for grinding and crushing. A hard impact or biting on a very hard object can easily fracture the incisor's fine edge, illustrating the direct trade-off between a sharp cutting tool and structural robustness.
6. How do the incisors of humans compare to those found in herbivores and carnivores?
The structure of incisors is a classic example of evolutionary adaptation to diet:
- Humans (Omnivores): Our incisors are relatively unspecialised—sharp enough to cut, but not overly large or continuously growing. They are versatile for a mixed diet.
- Herbivores (e.g., Rabbits, Beavers): These animals often have large, prominent incisors that grow continuously throughout their lives. This is an adaptation to counteract the wear from constantly gnawing on tough plant material.
- Carnivores (e.g., Cats, Dogs): Their incisors are often small and peg-like. They are used mainly for nibbling meat off bones or for grooming, as the large canine teeth are the primary tools for capturing and tearing prey.
7. What is the significance of incisors in the human dental formula?
The human permanent dental formula is written as 2.1.2.3 / 2.1.2.3. This formula represents the number and type of teeth in one-quarter of the mouth (e.g., the upper right side). In this formula:
- The first number, '2', represents the incisors (one central and one lateral incisor).
This means in a full set of 32 teeth, a human has a total of 8 incisors (2 per quadrant x 4 quadrants). The dental formula is a standardised biological tool used to classify mammals and understand their dietary adaptations based on their tooth structure.
