Parts of A Tooth

Teeth are essential for mastication(chewing) but beyond this function, teeth serve multiple functions including shaping the kinetics of phonation(speech), breathing, maintaining a patent airway, and serving as the foundation for the shape of the face. The maxilla(upper jaw) and mandible(lower jaw), which together form the jaw, contain alveolar bone, a thick ridge of bone that forms the sockets of the teeth.

Mastication or the chewing process involves cutting, mixing, and grinding food to allow the oropharynx and tongue to shape it into a bolus(ball-like mixture of food and saliva) that can be swallowed.

Parts of the tooth include the crown, neck, and root. The portion of the tooth i.e exposed to the oral cavity is known as the dental crown and the portion below the crown is known as the root. The crown portion of the tooth consists of enamel, dentin, and some portion of the pulp. The root portion of the tooth consists of root canals, cementum, and alveolar bone (bone surrounding the tooth). The dental pulp cavity exists in the center of the tooth, within which the nerves and blood vessels pass through which the tooth gets its blood and sensory supply. The tooth is supported by the tissue consisting of the alveolar bone, gingiva(gums), and periodontal ligament.

Parts Of A Tooth In Brief #

Enamel #

Enamel is a thin outer covering of the tooth. This is the hardest substance in the human body due to its tough shell. It is hard as a crystal(7 on the Mohs scale of mineral hardness). It covers the crown portion of the tooth that is visible outside of the gingiva. Due to its translucent property, one can see the light through it. Enamel is comprised of the mineral calcium phosphate, arranged in a crystal structure known as hydroxyapatite.

Dentin #

Dentin or dentine is a second layer of the teeth present underneath the enamel. It is one of the four major components of the tooth which comprises of 55% mineral, 30%organic material like collagen, and 15%fluid. But dentin composition varies with age and tooth type. The organic portion i.e collagen is surrounded by water, and hydrogen bonding exists between the strands of the collagen.

Cementum #

Cementum is the layer that covers the surface of the root. It connects the alveolar bone with the tooth by a periodontal ligament. Cementum is slightly softer than dentin and its composition includes 45% to 50% inorganic material i.e hydroxyapatite by weight and 50% to 55% organic matter and water by weight. The organic portion of cementum is primarily composed of proteoglycans and collagen.

Dental Pulp #

Dental pulp is an unmineralized part of the tooth composed of soft connective tissue, vascular, lymphatic, and nervous elements that occupy the central pulp cavity. The pulp is a soft, gelatinous part of the tooth. It contains 75-80% of water.

Periodontal Ligament #

Periodontal ligament is like all soft fibrous connective tissues, it consists of a fibrous stroma in a gel of ground substance containing cells, blood vessels, and nerves. The fibrous stroma consists primarily of collagen (with small amounts of oxytalan) and the cells are mainly fibroblasts.

Alveolar Bone #

The alveolar bone is also known as the alveolar process which is a thick ridge of bone containing the tooth sockets. It is located on the jaw bones that hold the teeth. Alveolar bone is composed of 67% inorganic material based on its weight. The mineral content is found in the form of calcium hydroxyapatite crystals. The remaining alveolar bone is made up of 33% organic material. The inorganic material of alveolar bone is composed primarily of calcium and phosphate.