Development of Teeth
Begins with teeth formation from the stage of embryonic cell growth to the eruption
in the mouth. Deciduous teeth start to develop in the embryo\uterus between the
sixth and eighth week and permanent teeth in the twentieth week.
Structure of Teeth and Supporting Structures
Teeth have a very complex structure. The outermost layer is called the enamel, the
bulk of the tooth is dentin and there is a coating of cementum on the outer surface
beneath the gum. In the center is the 'pulp' a living tissue with nerves, blood
vessels etc.
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Tooth Enamel is a protective tooth structure that covers the exposed part of a tooth,
the crown.
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Dentin is the tissue below the tooth enamel that forms the main mass of a tooth.
It supports the tooth enamel and absorbs the pressure of eating.
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Dental Pulp is a soft connective tissue containing nerves and blood vessels that
nourish the tooth.
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Cementum covers the dentine outside the root (under the gum line) and it is attached
to the bone of the jaw with little elastic fibres.
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Gums are the tough pink- coloured tissue that covers the bone of the jaw and supports
the tooth structure inside the alveolar bone.
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Periodontal Ligament consist of tough little elastic fibres that keep the tooth
attached to the jaw.
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Alveolar Bone is that part of the jaw bones that keeps the tooth in its place, feeds
and protects it.
Gum Pads
Gum pads are the alveolar arches, which at the time of birth are firm and pink.
The upper gum pad is horse shoe shaped and lower gum pad/arch is ‘U’s shaped or
rectangular in form. At rest the gum pads are separated by the tongue, which protrudes
over the lower gum pad to lie immediately behind the lower lip.
The oral cavity comprises of various structures such as:
- Teeth
- Tongue
- Gums
- Lips
- Palate
- Floor of the mouth
Types of Teeth
We have two different sets of teeth. The first set (called temporary, milk or deciduous
teeth) are 20 in number and are replaced during the growing stage of life by the
second set (called permanent teeth) which are 32 in number. There are 32 permanent
teeth and 20 deciduous teeth (milk teeth) arranged in pairs in the upper and lower
jaws.
There are 4 different types of teeth based upon their anatomical shape and position
in the mouth:
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Incisors are the front human teeth with rather flat surfaces and a straight sharp
horizontal edge for cutting and biting the food with one long, single, conical root.
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Canine teeth are very strong, pointed corner teeth for tearing and shedding. They
are larger and stronger than the incisors.
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Premolars are used for the chewing of the food, are placed lateral to and behind
the canine teeth, with a flat upper surface.
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Molars are the back teeth. They have the largest surface among the permanent teeth,
used for the final chewing and grinding of the food before swallowing.
Primary/ Milk/ Deciduous Teeth
These are the first teeth of a child. They are already formed in the jaw although
they can't be seen. The baby starts teething around six months of age and by three
years all twenty teeth have erupted.
Important for-
- Mastication or chewing food for easy digestion.
- Speech develops with the help of tongue, cheek and the primary teeth.
- Aesthetics depends on attractive, well aligned healthy teeth.
- Space maintenance are advised for the permanent teeth to erupt.
