Tooth Morphology Chapter 1

Basic terminology, identification systems, tooth structures, and periodontal tissues covered in the first chapter of Tooth Morphology.

Dentition

All teeth in the mouth together.

Primary dentition

The set of teeth that lasts during childhood.

Permanent (secondary) dentition

The set of teeth that hopefully lasts through adulthood.

Mixed dentition

A mix of primary and permanent teeth present in the mouth at the same time.

Maxillary arch

Teeth located in the upper jawbone.

Mandibular arch

Teeth located in the lower jawbone.

Incisors

Teeth shaped to incise and cut off pieces of food.

Canines

Teeth shaped to pierce and hold on to food.

Molars

Teeth shaped to grind food.

Anterior

Teeth located in the front of the mouth.

Posterior

Teeth located in the back of the mouth.

Universal Numbering System (Primary)

Identification system for primary teeth using letters A through T.

Universal Numbering System (Permanent)

Identification system for permanent teeth using numbers 1 through 32.

Enamel

White, protective external surface layer of the anatomic crown containing $95\%$ calcium hydroxyapatite.

Cementum

Dull yellow external layer of the anatomic root.

Dentin

Hard yellowish tissue underlying the enamel and cementum that makes up the bulk of the inner portion of the crown and root.

Pulp

Soft, nonmineralized connective tissue containing blood vessels and nerves.

Anatomic crown

The portion of the tooth covered by enamel.

Anatomic root

The portion of the tooth covered by cementum.

Clinical crown

The amount of the tooth that is visible in the oral cavity.

Clinical root

The portion of the tooth that is not visible in the oral cavity.

Cementoenamel junction (CEJ)

The junction between the enamel and the cementum.

Dentinoenamel junction (DEJ)

The inner surface of the enamel where it joins the dentin.

Cementodentinal junction (CDJ)

The inner surface of the cementum where it joins the dentin.

Pulp chamber

The coronal portion of the pulp cavity located toward the crown.

Pulp canal (root canal)

The portion of the pulp cavity located toward the roots.

Apical foramen

Holes near the root tip (apex) through which nerves and blood vessels enter the pulp canals.

Periodontium

The supporting tissues of the teeth in the mouth.

Alveolar bone

The portion of the bone that surrounds the roots of the teeth.

Gingiva

The soft tissue in the mouth that covers the alveolar bone.

Gingival sulcus

The space between the free gingiva and the tooth.

Periodontal ligament

Tissue that connects the cementum to the alveolar bone.

Facial

Surface refers to either anterior (labial) or posterior (buccal) tooth surfaces.

Labial

The surface of anterior teeth toward the lips.

Buccal

The surface of posterior teeth toward the cheeks.

Proximal surfaces

Identify surfaces between teeth, which include mesial and distal surfaces.

Mesial

Tooth surfaces toward the midline.

Distal

Tooth surfaces away from the midline.

Lingual

The surface of the tooth on the tongue side.

Incisal

The biting edges of anterior teeth.

Occlusal

The chewing surface of posterior teeth.

Line angle

The junction where two tooth surfaces meet, such as distolabial or mesiobuccal.

Point angles

The junction of three surfaces at a point, such as mesiobucco-occlusal.

Apical third

The horizontal division of the root closest to the root tip.

Cervical third

The horizontal division of the crown or root closest to the cementoenamel junction.

Root to crown ratio

Root length divided by crown length, which is normally greater than $1.0$.