Chapter 9 Tooth Morphology

Agenesis

Occurs when the tooth buds do not form.

Anatomical Crown

Portion of the tooth covered with enamel.

Anatomical Root

The portion of the tooth covered with cementum.

Apex

At or near the end of the root.

Apical Foramen

An opening in the end of the tooth through which nerve and blood vessels.

Apical Third

The root of the tooth is divided into imaginary thirds with the area nearest the apex as the apical third.

Bicanineate

A Larger single buccal cusp and a lingual cusp.

Bicuspids

Another term used for premolars- they have two cusps.

Bifurated

One tooth with two roots.

Buccal

The surface of the posterior tooth that is toward the cheeks.

Buccal Groove

A linear depression forming a groove that extends from the middle of the buccal surface to the occlusal surface of the tooth.

Canine

Cuspid; third tooth from the mid-line; bulkier and aids in tearing food.

Canine Eminence

A bony ridge covering the labial portion of the roots.

Central Incisor

The first starting from the mid-line; used to cut or bite the food that is ingested.

Central Groove

Most prominent developmental groove on the occlusal surface of the posterior teeth.

Cervical Line

Where the anatomical crown and root join.

Cervical Third

The area on the crown of the tooth that is nearest the cervical( or nearest the gingival.)

Cingulum

A convex area on the lingual surface of the anterior teeth near the gingiva.

Clinical Crown

Exposed coronal portion of the crowns.

Clinical Root

The portion of the root seen in the oral cavity.

Concave

Recessed or indented.

Contract Area

The proximal sides of where two teeth come together and touch; normally the medial of one tooth and the distal of another tooth.

Convex

To bulge or curve outward.

Crown

Top or highest part of a tooth; often called a cap.

Cusp

Pointed or rounded mounds on the crown of the tooth.

Cusp of Carabelli

A fifth cusp on the mesial lingual surface of most maxillary first molars.

Deciduous

Primary.

Dentition

Natural teeth in position.

Developmental Groove

Groove formed by the uniting of lobes during development of the crown of the tooth.

Diastema

A space between two teeth.

Distal

The surface of the tooth that is away from the midline.

Embrasure

The triangular space in the gingival direction that is made when two adjoining teeth are contacting.

Exfloiated

Shed from the oral cavity.

Facial

Either the labial surface of the anterior teeth or the buccal surface of the posterior teeth.

Fissure

A developmental groove that has an imperfect union where the lobes join.

Fossa

A shallow, rounded, or angular depression.

Furcation

The dividing point of a multirooted tooth; division of the roots.

Imbrication lines

Slight ridges that run mesiodistally in the cervical third of the teeth.

Incisal Edge

Cutting or tearing edge of the anterior teeth.

Incisal Third

The area on the crown of the tooth that is nearest the incisal edge on the anterior tooth.

Interproximal

Ridographs; also known as bitewing radiographs.

Labial

The " inside" surface which is toward the lips.

Iateral Incisor

The second tooth from the midline used for cutting.

Lingual

Surface of the tooth that is toward the tongue.

Lobes

Divisions that join to form a tooth; often in moloars, lobes become cusps.

Mamelons

Three bulges on the incisal edge of a newly erupted central incisor.

Mandibular Arch

Lower arch in the dentition.

Marginal Groove

Developmental groove that provides a spillway for food to escape during chewing.

Marginal Ridges

Elevated areas of enamel that form the mesial and distal borders of the lingual surface on the anterior teeth and the mesial and distal borders of the occlusal surface of the posterior teeth.

Maxillary Arch

Upper arch in the dentition.

Mesial

Surface of the tooth toward the midline.

Middle Third

The root of the tooth is divided into imaginary thirds with the area between the incisal third and the cervical third is called the middle third.

Mixed Dentition

The period when primary teeth and permanent teeth in the dentition lasing from appoximately 6 to 12 years of age.

Molars

Molars are used to chew food, found in the posterior in maxillary and mandibular arches.

Nonsuccedaneous

Pertain to the teeth that do not replace primary teeth.

Oblique Ridge

Elevated area of enamel that extends obliquely across the occlusal of the tooth.

Occlusal

Chewing surface of the molars and premolar teeth.

Occlusal Third

The area on the crown of the tooth that is nearest the occlusal surface of the posterior tooth.

Peg Lateral

A diminutive, peg-shaped crown with a smooth surface lacking contact on the mesial and distal surfaces.

Permanent Teeth

Second set of teeth humans grow.

Pit

Area on the occlusal surface of the teeth where the grooves come together or the fissures cross.

Premolars

Often called bicuspids, used to pulverize the food. Two premolars are in each arch and are posterior to the canines.

Primary Teeth

First set of teeth humans grow. They are replaced with permanent teeth between ages 6 to 21.

Quadrants

Two sections formed by the imaginary line dividing the dental arches in two halves; actually there are four quadrants each containing eight permanent teeth.

Ridge

A linear elevation of enamel found on the tooth.

Root

Divided into anatomical and clinical portions; the anatomical root is covered with cementum and the clinical root is the root seen in the oral cavity.

Sextants

Dividing the dental arches into sixths.

Succedaneous

Permanent teeth that replace primary teeth.

Supplemental Groove

Shallow Linear grooves that radiate from the developmental grove.

Tooth Morphology

The study of the structure and form of teeth.

Transverse

The union of two triangular ridges produces a single ridge of elevation across the occlusal surface of a posterior tooth.

Triangular Ridge

Ridge or elevation that descends from the cusp and widens as it runs downward to the middle area of the occlusal surface.

Tricanineate

A three-cusp type of mandibular second premolar.

Trifurated

When there are three roots coming from the main truck of the tooth.