teeth structure Flashcards
Enamel
The hardest, white outer part of the tooth. Enamel is mostly made of calcium phosphate, a rock-hard mineral.
Dentin
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
Pulp
The softer, living inner structure of teeth. Blood vessels and nerves run through the pulp of the teeth.
Cementum
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?
32
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.
Crown
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.
root
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.
Bone
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.
Molars
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).