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Flashcards in teeth structure Deck (18)
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The hardest, white outer part of the tooth. Enamel is mostly made of calcium phosphate, a rock-hard mineral.



A layer underlying the enamel. It is a hard tissue that contains microscopic tubes. When the enamel is damaged, heat or cold can enter the tooth through these paths and cause sensitivity or pain



The softer, living inner structure of teeth. Blood vessels and nerves run through the pulp of the teeth.



A layer of connective tissue that binds the roots of the teeth firmly to the gums and jawbone.


How many teeth does a normal adult have?

Incisors (8 total): The middlemost four teeth on the upper and lower jaws.
• Canines (4 total): The pointed teeth just outside the incisors.
• Premolars (8 total): Teeth between the canines and molars.
• Molars (8 total): Flat teeth in the rear of the mouth, best at grinding food.


How many wisdom teeth does the average adult have and why are they often removed?

These teeth erupt at around age 18, but are often surgically removed to prevent displacement of other teeth.



projects into the mouth
The crown of a tooth is that part of the tooth which is covered with enamel and this is the part usually visible in the mouth.



descends below the gum line, into the jaw.


Periodontal ligament

Made up of thousands of fibres which fasten the cementum to the bony socket. These fibres anchor the tooth to the jaw bone and act as shock absorbers for the tooth which is subjected to heavy forces during chewing


Gingivae() (gums):

Soft tissue that immediately surrounds the teeth and bone. It protects the bone and the roots of the teeth and provides an easily lubricated surface.



Provides a socket to surround and support the roots of the teeth.


Nerves and blood supply:

Each tooth and periodontal ligament has a nerve supply and the teeth are sensitive to a wide variety of stimuli. The blood supply is necessary to maintain the vitality of the tooth.


Periodontal ligament:

Tissue consisting mainly of the fibrous tissue that connects the tooth root and the alveolar bone. It prevents force applied to the tooth from being directly imposed on the alveolar bone while chewing food.


Canine Teeth

The canines are the third permanent teeth from the center of the mouth to the back in the upper and lower jaws. There are a total of 4 canines, two in the upper jaw and two in the lower.
They are used to tear food.



The teeth located behind the canines grind food like a mill. In milk teeth, there are two molars, each on the left and right sides of the upper and lower jaws. In permanent teeth, there are two premolars and molars each on the left and right sides of the upper and lower jaws, for a total of 16 molar teeth (20 when counting the wisdom teeth).


Milk teeth and permanent teeth

With the growth of the body, the jaw grows bigger. As the jaw grows, children’s teeth, or “milk teeth” are replaced by adult teeth known as “permanent teeth”. When all of a child`s permanent teeth have emerged, the chewing force becomes stronger, enabling them to eat various types of food easily. Permanent teeth are very important teeth, which a person uses for the entire course of their life


Difference between milk teeth and permanent teeth

Color: Milk teeth are almost white, and permanent teeth have a yellow-tinge.
Size: Milk teeth are a size smaller than permanent teeth.
Teeth quality: Both enamel and dentin are thinner in milk teeth; therefore, caries in milk teeth progress more quickly.


Transition from milk teeth to permanent teeth

Human teeth only transition from milk teeth to permanent teeth once. All of the milk teeth emerge at an age from two to three; however, since the jaw bone continues to grow, the sizes of the teeth and the jaw gradually become imbalanced. When the cells that break down the tissue appear around the roots of the milk teeth, the roots gradually dissolve and are absorbed, becoming shorter in height.
When the permanent teeth become large enough, the milk teeth naturally start to fall out. By about age 12, all of the milk teeth are replaced by 28 permanent teeth