အောက်ဆုံးထိ ဆွဲကြည့်ပေးကြပါ ခင်ဗျာ
Your teeth are part of your digestive system. They break down foods by crushing or cutting them before you swallow. Most humans have 32 teeth, although some have more and some have fewer. Enamel (the protective outer layer of your teeth) is the hardest substance in the human body.
What are teeth?
Your teeth play a big role in digestion. They cut and crush foods, making them easier to swallow.
Though they look more like bones, teeth are actually ectodermal organs. Other ectodermal organs include your hair, skin and sweat glands.
How many teeth do humans have?
Most adults have 32 permanent teeth. But some people are born with missing teeth (hypodontia), and some people have extra teeth (hyperdontia).
Most children have 20 primary teeth that grow in (erupt) between the ages of 4 months old and 6 years old. These are baby teeth that’ll eventually fall out and make room for permanent adult teeth.
What are the four types of teeth?
We have different types of teeth, and each type serves an important purpose. There are four types of permanent teeth in humans:
Your incisors are the most visible teeth in your mouth. Most people have four incisors on the upper jaw and four on the lower. These include your front two teeth and the teeth on either side of them.
Each incisor has a single narrow edge, which helps cut into food when you bite.
Canine teeth get their name because they resemble a dog’s fangs. They’re pointier than other types of teeth. Most people have four canine teeth — one in each quadrant (upper right, upper left, lower right, lower left).
Canine teeth help you tear into foods like meat and crunchy vegetables. Sometimes, people call canines “eye teeth” because of their position directly under your eyes.
Also called bicuspids, premolars sit between your canines and your molars (the teeth in the back of your mouth).
Premolar teeth have features of both canines and molars. They help you tear, crush and grind food into smaller pieces.
Your molar teeth are in the very back of your mouth. Most of your chewing — about 90% — takes place here. Most adults have 12 molar teeth — three in each quadrant.
Molar teeth include wisdom teeth (third molars). So, if you’ve had your wisdom teeth removed, or if you were born without them, then you probably have eight molars altogether.
Because molars are your main chewing teeth, they’re good for crushing and grinding up your food.
What’s the anatomy of a tooth?
A tooth consists of two main structures:
- Crown. This is the part of your tooth that you can see — the portion above your gums. Enamel — a hard, protective substance — covers your tooth crown.
- Root. This is the part of your tooth that holds it in your jaw. You can’t see the root because your gums cover it. The root anchors your tooth to your periodontal ligament (the soft connective tissue that lines your tooth socket).
What are teeth made of?
Your teeth have four main layers, including:
- Enamel. This is the protective outer layer of each tooth. Enamel helps shield your teeth from cavity-causing bacteria. Enamel is the hardest substance in the human body.
- Dentin. Just underneath your enamel, there’s a layer of dentin. Dentin isn’t as strong as enamel. When missing enamel exposes dentin, your risk for cavities increases.
- Cementum. Cementum covers your tooth root. Along with your periodontal tissues, it helps anchor your tooth firmly in your jaw.
- Tooth pulp. This is the innermost layer of your tooth. It contains nerves, blood vessels and connective tissues.
Are teeth bones?
No. Although teeth resemble bones, they’re actually quite different. Bones can regenerate (repair) when they’re broken. Teeth can’t. Unlike bones, your teeth don’t contain marrow.
- What is the nervous system?
- What is a bulletproof vest made of?
- Avulsed Tooth: What is an Avulsed Tooth?
- What is the mail function of teeth?
- What is a fact about Irrawaddy dolphin?
- What is the characteristics of salmon fish?