Human Tooth, Tooth Decay
human tooth , tooth decay
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Human tooth
Teeth of humans are small, calcified, whitish structures found in the mouth that are used to break down food. The roots of teeth are embedded in the maxilla (upper jaw) or the mandible (lower jaw) and are covered by gums. Teeth are made of multiple tissues of varying density and hardness.
Teeth are among the most distinctive (and long-lasting) features of mammal species. Humans, like other mammals, are diphyodont, meaning that they develop two sets of teeth. The first set (also called the "baby", "milk", "primary", and "deciduous" set) normally starts to appear at about six months of age, although some babies are born with one or more visible teeth, known as neonatal teeth. Normal tooth eruption at about six months is known as teething and can be painful.
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Structure of Human Tooth
The teeth are the hardest substances in the human body. Besides being essential for chewing, the teeth play an important role in speech. Parts of the teeth include:
• 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. Dentin is made of living cells, which secrete a hard mineral substance.
• 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.
• Periodontal ligament: Tissue that helps hold the teeth tightly against the jaw.
• Crown : Exposed part of tooth
• Root : Part embedded in jaw
• Jaw Bone : Sockets for teeth
• Gum : Protects jaw bones and roots of teeth
[pic]
Dental formula
Because mammalian teeth are specialized for different functions, many mammal groups have lost teeth not needed in their adaptation. Tooth form has also undergone evolutionary modification as a result of natural selection
[pic]
Human tooth
Teeth of humans are small, calcified, whitish structures found in the mouth that are used to break down food. The roots of teeth are embedded in the maxilla (upper jaw) or the mandible (lower jaw) and are covered by gums. Teeth are made of multiple tissues of varying density and hardness.
Teeth are among the most distinctive (and long-lasting) features of mammal species. Humans, like other mammals, are diphyodont, meaning that they develop two sets of teeth. The first set (also called the "baby", "milk", "primary", and "deciduous" set) normally starts to appear at about six months of age, although some babies are born with one or more visible teeth, known as neonatal teeth. Normal tooth eruption at about six months is known as teething and can be painful.
[pic]
Structure of Human Tooth
The teeth are the hardest substances in the human body. Besides being essential for chewing, the teeth play an important role in speech. Parts of the teeth include:
• 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. Dentin is made of living cells, which secrete a hard mineral substance.
• 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.
• Periodontal ligament: Tissue that helps hold the teeth tightly against the jaw.
• Crown : Exposed part of tooth
• Root : Part embedded in jaw
• Jaw Bone : Sockets for teeth
• Gum : Protects jaw bones and roots of teeth
[pic]
Dental formula
Because mammalian teeth are specialized for different functions, many mammal groups have lost teeth not needed in their adaptation. Tooth form has also undergone evolutionary modification as a result of natural selection