Human Teeth

Human Teeth

Human Teeth Structure of Human Tooth: • Tooth has two anatomical parts. Crown: Covered with enamel and visible. Root: Embedded in the jaw. Its function is anchorage. Not visible. • Enamel The hard outer layer of the crown. Enamel is the hardest substance in the body. • Dentine Not as hard as enamel, forms the bulk of the tooth and can be sensitive if the protection of the enamel is lost.

• • •

•

Human Teeth Pulp Soft tissue containing the blood and nerve supply to the tooth. The pulp extends from the crown to the tip of the root. Cementum The layer of bone-like tissue covering the root. It is not as hard as enamel.

Human Teeth

Human Teeth Types of Human Teeth: • Adult humans typically have 32teeth. • 16 in upper jaw • 16 in lower jaw • Humans are heterodonts i.e have teeth of different sizes and shapes that serve different functions. • In animals homodont teeth. • Humans have four types of teeth depending on size, shape and function.

Human Teeth Incisors: • Eight incisors in adult. Located at front of mouth. • 4 in upper jaw and 4 in lower jaw. • Have edge used to cut food. Canines: • Located on either side of incisors. • Two canines in each jaw. • Pointed in nature. • Primary role is to tear food.

Human Teeth

Human Teeth Premolar: • Located behind canines. • Flat in nature. • Two sets of four premolars in each jaw. • Function is to grind food. Molar: • Located behind the premolars. • 12 molars. Three sets in each jaw. • Referred to as first, second and third. • Involved in vigorous chewing. • Third molars are called wisdom teeth.

Human Teeth Tooth Development: Deciduous Teeth: • Humans are diphyodonts. • First set of teeth is deciduous. • 20 in number. Also called baby teeth/milk teeth. • Star developing after two months of conception. • Natal teeth: One or two teeth baby caries at birth. Permanent Teeth: • Appear at the age of six year. • Wisdom teeth erupt by the age of 21.