Teeth (singular,Tooth) are small white structures found in the jaws (or mouths) of many vertebrates that are used to tear, scrape, milk and chew food.

Some animals, particularly carnivores, also use teeth for hunting or defense.

The roots of teeth are covered by gums. The teeth however, are not made of bone.

Teeth are among the most distinctive (and long-lasting) features of mammal species.

Paleontologists use teeth to identify fossil species and determine their relationships.

The shape of the animal’s teeth are related to its diet. For example, plant matter is hard to digest, so herbivores have many molars for chewing. Carnivores, on the other hand, need canines to kill and tear meat.

A tooth is made up of 3 elements

Water

Organic materials

Inorganic materials

Enamel: The thin outer covering of a tooth which is highly calcified.

It covers the crown of the tooth.

It is the hardest and highly mineralized tissue part in the body.

Enamel is made of inorganic minerals calcium phosphate, arranged in a crystal structure known as hydroxyapatite.

Dentin constitutes 20% organic and 70% inorganic hybrid material.

Cementum: thin layer of minerals covering the dentin, softer than enamel and dentine, anchors the tooth to the alveolar bone

Apical foramen: an opening at root apex where nerves and blood vessels enters the tooth

Human dentition appears in two sets

Primary/deciduous dentition

Secondary/permanent dentition

Contains a set of 20 teeth

Begins to form during the first trimester of pregnancy

Typically begin eruption around 6 months of age

Most children complete eruption at age 3

Deciduous teeth are usually lost and replaced by permanent teeth, but in the absence of permanent replacements, they can remain functional for many years.

The deciduous dentition is made up of

central incisors,

lateral incisors,

canines,

first molars, and

second molars;.

All of these are replaced with a permanent counterpart except for the first and second molars; they are replaced by premolars.

The deciduous teeth will remain until the age of six.

At that time, the permanent teeth start to appear in the mouth resulting in mixed dentition.

The erupting permanent teeth causes root resorption, where the permanent teeth push down on the roots of the deciduous teeth causing the roots to be dissolved and become absorbed by the forming permanent teeth.

The process of shedding deciduous teeth and the replacement by permanent teeth is called exfoliation.

This may last from age six to age twelve. By age twelve there usually are only permanent tooth remaining.

Permanent teeth are the second set of teeth formed in humans.

The first permanent tooth usually appears in the mouth at around six years of age, and the mouth will then be in a transition period with both deciduous teeth and permanent teeth (mixed dentition) until the last deciduous tooth is lost

The first of the adult teeth to erupt are the permanent first molars that come through the gums at the back, right behind the last ‘milk’ molars.

These first permanent molars are the most important teeth for the correct development of an adult dentition.

Up to the age of thirteen years twenty-eight of the thirty-two permanent teeth will appear.

The full permanent dentition is completed much later.

The four last adult teeth, one at the back of every arch will appear between the ages of seventeen and twenty-one years.

This is the reason they are named wisdom teeth

SIZE-The deciduous teeth are generally smaller than permanent one

FORM-The crown of deciduous teeth are more bulbous than those of the permanent teeth. The cusps of the deciduous teeth are more pointed and less rounded

COLOUR-The crown of the deciduous teeth are lighter in colour (white) than the permanent one

Structure: incisors of permanent teeth have mamelons which wear out as time goes

ROOT-Root of the deciduous teeth are shorter and less robust than those of permanent one

ATTRITION-The deciduous teeth shows a greater degree of attrition than that shown by the permanent teeth

PULP CAVITIES- Compare to the size of the teeth, the pulp cavity of the deciduous teeth are larger than the those of the permanent ones.

Permanent teeth

Deciduous teeth

Components of a tooth are enamel,dentine,cementum,pulp chamber and pulp contents

Primary dentition contains 20 teeth while permanent dentition contains 32 teeth

Features of primary teeth vary from those of permanent teeth by size,form,root and color