Teeth

The teeth are highly specialised calcified structures located within the alveolar sockets of the maxilla and mandible. They are essential components of the oral cavity and play important roles in mastication, speech articulation, facial aesthetics, and maintenance of occlusion. Humans develop two sets of teeth during life: the deciduous (primary) dentition and the permanent dentition.

Types of teeth

An adult normally possesses 32 permanent teeth arranged in the dental arches as:

• 8 incisors

• 4 canines

• 8 premolars

• 12 molars (including third molars)

Sub-parts

Each tooth consists of three main parts:

• Crown - the visible part above the gingiva covered by enamel.

• Neck - the constricted region at the cemento-enamel junction.

• Root - the embedded portion anchored within the alveolar bone by the periodontal ligament.

Tissue composition

The teeth comprise of four principal tissues:

• Enamel - the hardest substance in the teeth, covering the crown and providing protection against wear.

• Dentin - a calcified tissue forming the bulk of the teeth, beneath enamel and cementum.

• Cementum - a bonelike tissue covering the root surface and providing attachment for periodontal ligament fibres.

• Dental pulp - soft connective tissue within the pulp cavity containing blood vessels, nerves, and lymphatics. The pulp is located within the crown region where it forms the main pulp chamber and it also extends into the root canals within the roots of the teeth.

Teeth are attached to the alveolar bone by the periodontal ligament, which acts as a suspensory apparatus and shock absorber during mastication.

Functions

Mastication, speech articulation, maintenance of facial contour, and contribution to occlusion and jaw stability.

Blood Supply

The teeth are supplied by branches of the maxillary artery:

• Superior alveolar arteries supply maxillary teeth

• Inferior alveolar artery supplies mandibular teeth

Innervation

Sensory innervation is provided by branches of the trigeminal nerve:

• Maxillary teeth: superior alveolar nerves (CN V2)

• Mandibular teeth: inferior alveolar nerve (CN V3)