BASIM ZWAIN LECTURESDENTAL ANATOMY

PERMANENT MAXILLARY INCISORS

Professor Dr. Basim ZwainFaculty of DentistryUniversity of Kufa

Basim.zwayen@uokufa.edu.iq

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PERMANENT MAXILLARY INCISORS

Characteristic features of incisors’ crowns

1- Incisal ridge and edge.

2- Mamelons.

3- Position of the marginal ridges.

4- Lingual fossa and cingulum.

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Principal identifying features1- The widest anterior tooth mesiodistally.2- Squared or rectangular.3- Straight mesial and rounded distal outline.4- Sharp mesial and rounded distal incisal angle.5- Mamelons in newly erupted incisors.6- Well marked marginal ridges, lingual fossa, and cingulum.

MAXILLARY CENTRAL INCISOR

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Labial aspect

The mesial outline is slightly convex with a crest of curvature near the mesioincisal angle.

The distal outline is more convex than mesial outline, with crest of curvature at the junction between incisal and middle third.

The incisal outline in newly erupted teeth has elevation called the mamelons, but with age the mamelons wear and a regular and straight incisal outline is seen.

MAXILLARY CENTRAL INCISOR

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MAXILLARY CENTRAL INCISOR Labial aspect

The cervical outline is semicircular in shape with the curvature rootwise.

The root is cone shaped with a blunt apex. It is 2-3mm longer than the crown.

The labial surface is a broad flattened convexity divided vertically by 2 shallow developmental depressions.

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MAXILLARY CENTRAL INCISOR

Lingual Aspect The crown and root taper lingually, therefore the mesiodistal dimension of the lingual surface is narrower than of the labial surface. Below the cervical line there is a smooth convexity called the cingulum, which is confluent with raised marginal ridges, mesially and distally. Between the lingual portion of the incisal ridge, the mesial and distal marginal ridges and the cingulum, is a shallow concavity called the lingual fossa.

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MAXILLARY CENTRAL INCISORMesial Aspect The crown is triangular in shape, with the base of the triangle at the cervix, and the apex at the incisal ridge. A line which bisects the outline of the crown will bisect the root. The labial outline of the crown is slightly convex. The lingual outline of the crown is convex at the cingulum, then becomes concave at the mesial marginal ridge, and then slightly convex at the incisal ridge. The cervical line curves incisally more than any surface on any tooth. The curvature is about 3-4mm.

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MAXILLARY CENTRAL INCISORDistal Aspect

The curvature of the cervical line is less distally than mesially.

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MAXILLARY CENTRAL INCISORIncisal Aspect The incisal ridge is centered over the root. The labial outline of the crown is broad and flat convex. The incisal edge and incisal ridge are well defined. Tapers lingually to cingulum. Labial mesiodistal dimension is greater than lingual.

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Thank you