Anatomic landmarks

The crown of a tooth can be used to describe two situations. The anatomic crown of a tooth is designated by the area above the cementoenamel junction (CEJ) and is consequently covered in enamel. Also, it is possible to describe the clinical crown of a tooth as any parts visible in the mouth, but frequently the anatomic crown is meant when the term is used. The majority of the crown is composed of dentin, with the pulp chamber found in the center. The crown is only found within bone before eruption into the mouth. Afterwards, it is almost always visible.

The anatomic root is found below the cementoenamel junction and is covered with cementum, whereas the clinical root is any part of a tooth not visible in the mouth. Similarly, the anatomic root is assumed in most circumstances. Dentin composes most of the root, which normally have pulp canals. The roots of teeth may be single in number or multiple. Canines and most premolars, except for maxillary first premolars, usually have one root. Maxillary first premolars and mandibular molars usually have two roots. Maxillary molars usually have three roots. The tooth is supported in bone by an attachment apparatus, known as the periodontium, which interacts with the root.

Surfaces

Surfaces that are nearest the cheeks or lips are referred to as facial, and those nearest the tongue are known as lingual. Facial surfaces can be subdivided into buccal (when found on posterior teeth nearest the cheeks) and labial (when found on anterior teeth nearest the lips). Lingual surfaces can also be described as palatal when found on maxillary teeth beside the hard palate.

Surfaces that aid in chewing are known as occlusal on posterior teeth and incisal on anterior teeth. Surfaces nearest the junction of the crown and root are referred to as cervical, and those closest to the apex of the root are referred to as apical. The words mesial and distal are also used as descriptions. Mesial signifies a surface closer to the median line of the face, which is located on a vertical axis between the eyes, down the nose, and between the contact of the central incisors. Surfaces further away from the median line are described as distal.

Cusp

A cusp is an elevation on an occlusal surface of posterior teeth and canines. It contributes to a significant portion of the tooth's surface. Maxillary and mandibular canines have one cusp. Maxillary premolars and the mandibular first premolars usually have two cusps. Mandibular second premolars frequently have three cusps--- one buccal and two lingual. Maxillary molars have two buccal cusps and two lingual cusps. A fifth cusp that may form on the maxillary first molar is known as the cusp of Carabelli. Mandibular molars may have five or four cusps.