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Tooth Morphology

Tooth Morphology – Anatomic Characteristics Shown by Different teeth types:

  1. Permanent teeth

Features Common to all Incisors in Tooth Morphology

They have a single, cone-shaped, tapering root. The incisal edge of newly erupted teeth show mamelons. The crowns are triangular when viewed from proximal aspect.  The crowns do not have any linear faults. The facial surface is convex and the lingual surface is concave in the incisal half.

Features Common to all Canines in Tooth Morphology

They have a single root, which is longest and strongest of all the teeth. They have a single conical cusp. They have a functional lingual surface.

Features Common to all Premolar Teeth in Tooth Morphology

They have two or more cusps. They have one buccal cusp and one or more lingual cusps.

Features Common to all Molar Teeth in Tooth Morphology

They are the largest teeth of dentition. They have a box like crown with five surfaces. The occlusal surface is adopted for grinding. They have strong and long roots to withstand grinding stress.

  1. Deciduous Teeth

Features Common to all Incisors in Tooth Morphology

They have a single, cone-shaped, tapering root. They are smaller than permanent incisors. The cervical margin is prominent. Mamelons at the incisal margin is not seen. The cingulum is relatively more prominent.

Features Common to all Canines in Tooth Morphology

They resemble permanent canines, though are shorter. Mesial incisal ridge is longer than distal incisal ridge.

Features Common to all Molar Teeth in Tooth Morphology

They have two to three roots. The roots are divergent. They show a prominent cervical bulge buccally. The occlusal surface is relatively narrow bucco-lingually. Root trunk is absent.  Show a constricted cervical region.

ANATOMIC LANDMARKS OF THE TEETH in Tooth Morphology

Teeth can differ from person to person, as well as within the oral cavity. However, all teeth contain some of the same developmental anatomical landmarks. The following section presents some of these common characteristics.

Pits

A pit is a small, deep point on the lingual, occlusal or buccal surface of both maxillary and mandibular molars. Pits usually occur where several developmental lines converge. It is usually situated at the junction of developmental grooves or at terminals of these grooves.

Fissures in Tooth Morphology

A fissure is a linear fault along a developmental groove (line). Fissures are formed by the convergence of the separate enamel lobes. Lobes are developmental segments of a tooth. When lobes do not join correctly on the occlusal surface, deep grooves are formed. These grooves are called fissures.

Fossa

The fossa is a rounded depression on the surface of tooth. It occurs commonly on occlusal surfaces of posterior teeth and lingual surfaces of anterior teeth. Occiusal fossae may be either central or triangular.

Developmental Grooves in Tooth Morphology

Groove is a linear depression on the surface of the tooth. Developmental grooves (lines on the surface of the tooth) are the areas formed where the enamel lobes join on the occlusal surface. This union is generally a smooth and complete joint. Therefore, it differs from a fissure in composition. A developmental groove denotes the evidence of coalescence between the primary parts of the crown or root. It may be Buccal or Lingual and are seen on buccal and lingual surfaces of posterior teeth.

Lobe

The lobe is one of the main morphological divisions of the crown of a tooth. It is one of the primary centres of calcification. Cusps and mamelons are representative of lobes.

Cingulum

The cingulum is a rounded, raised portion of enamel. It is located on the lingual section of anterior teeth. It is usually located in the cervical third of lingual surface of the tooth.

Mamelon in Tooth Morphology

A mamelon is one of the three prominent, rounded protuberances of enamel located on the incisal edge of each newly erupted incisor. As the tooth is utilized, the mamelons wear down to a flat, functional incisal edge.

Cusps in Tooth Morphology

The cusps are raised, pointed, or rounded elevations of enamel. They are found on the occlusal surface of cuspids, premolars, and molars. It has an apex and four ridges.

Inclined Plane in Tooth Morphology

The inclined plane is a sloping area on occlusal surfaces of premolars and molars. Each cusp has two inclined planes.

Ridges in Tooth Morphology

A ridge is long, elevated portion on the surface of a tooth. It is called buccal, incisal and marginal ridge depending on its location. There are four basic ridges found on either molars, premolars, or incisors.

(i) A marginal ridge is a raised, rounded border of enamel that forms the mesial and distal margins of posterior teeth. Also, the marginal ridge forms the mesial and distal margins of the lingual surfaces of anterior teeth.

(ii) The triangular ridge descends from the cusp tip of bicuspids and molars to the occlusal depressions called fossa. There are not as many triangular ridges on a tooth as there are cusps.

(iii) The oblique ridge is a raised portion of enamel. It runs diagonally across the occlusal surface of molars from mesiolingual to disto-buccal.

(iv) The transverse ridge is a raised portion of enamel. The buccal and lingual triangular ridges form it. It is found on both premolars and molars.

Sulcus in Tooth Morphology

The sulcus is a long depression on the surface of a tooth, the inclines of which meet at an angle.

Tuberciein Tooth Morphology

A tubercie is a small rounded elevation of enamel on the crown of a tooth.

About Dr. Muna

Dr. Muna Taqi is a Dental surgeon from India who has more than 10 years of experience in the field of Oral & Maxillofacial surgery, Endodontics, & Pedodontics. She has worked in multinational medical corporates in Middle East and is also a consultant dental surgeon for many. She has authored many articles for medical journals & websites and is a consultant dental expert for Healthdrip.

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