Theeth

Theeth are calcified structures found in the jaws of most vertebrates, adapted for processing food through cutting, tearing, and grinding. In many species, theeth also contribute to facial structure and, in some cases, sound production or display. The outermost layer of the crown is enamel, the hardest substance in the vertebrate body; beneath lies dentin, and at the core is the pulp chamber containing nerves and blood vessels. The tooth is anchored to the jaw by cementum and a fibrous periodontal ligament, which helps absorb bite forces and allows limited movement.

The anatomical organization of theeth includes a crown that remains above the gumline and one or more roots embedded in the jaw. The surface forms and number of theeth vary among species, a condition known as heterodont dentition in mammals, where different tooth types serve distinct functions. In humans, theeth are organized into incisors, canines, premolars, and molars, with a primary (deciduous) set of 20 teeth and a permanent set of 32 teeth that typically erupts over several years.

Development and eruption of theeth begin in childhood and proceeds through coordinated stages, with primary teeth often shed to make way for permanent successors. Theeth health depends on careful oral hygiene, diet, and regular dental care. Common issues include caries (tooth decay) and periodontal disease, which can affect chewing ability and overall health if left untreated.