The mandibular central incisor is the most symmetrical tooth in the oral cavity. This tooth is fan-shaped with sharp incisal angles. The mamelons of this tooth usually wear off quickly, and they are only present right after the tooth erupts.

The distal and mesial surfaces of the mandibular central incisor are flat, and both taper towards the root of the tooth. The lobes and developmental grooves may not be present, or they can be not well developed and, therefore, hard to see.

The mandibular central incisor has an ultra-fine cingulum, lingual fossa and marginal ridges. Sometimes it can be challenging to identify these structures, but in that case, the names of the structures are still used for their corresponding areas on the lingual surface. The cingulum is located in the center of the tooth.

The height of the contour of the mandibular central incisor is as follows:

Mesial - incisal third;
Distal - incisal third;
Labial (facial) - close to the cervical line;
Lingual - close to the cervical line.

The distal surface of the tooth has a less curved cervical line towards the incisal edge than the cervical line on the mesial surface.

The root of this tooth buccolingually is broad and tapers towards the root apex. Also, it narrows mesiodistally, and this characteristic results in a so-called “bow-tie” root shape in cross-section studies.

The mandibular central incisor may present with mesial and distal root grooves (also called depressions). If the root has only one groove, it is usually the distal groove. But if it presents with both grooves, the distal groove tends to be more prominent.

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Mandibular central incisor