Teeth (singular tooth) are hard structures that protrude from the jaws of animals. They are made of collagen together with a form of calcium phosphate known as hydroxyapatite. The size, shape, structure, and number of teeth varies tremendously between species.
Each tooth is consists of 4 types of tissue:
Pulp- soft, made of connective tissue, nerves and blood vessels to nourish the tooth and has 2 parts (pulp chamber and root canal).
Dentin- tough yellow cover of the pulp which makes up most of the tooth.
Enamel- the toughest tissue covering the crown.
Cementum- bony layer beneath the gum line covering the root and holding the tooth in place. This makes the tooth resistant to chewing, bacteria and temperature change.
Types of Teeth
Incisors- 4 bottom and 4 top squarish and sharp teeth at the front and middle part.
Canines- 2 bottom and 2 top long sharp teeth beside the incisors.
Premolars- also called bicuspids, 2 bottom and 2 top behind each canine
Molars- There are 12 molars in an adult teeth behind the premolars. The third set is also called wisdom teeth.
Humans are diphyodont as we develop 2 sets of teeth. The first set is called milk, baby, primary, temporary or deciduous teeth. They start to develop before birth and push though the gums by 6 months to 1 year of age and fall out by 6 years old. This stage of teeth coming out is called eruption. The temporary teeth prepare and help placed the 32 permanent, secondary or adult teeth.