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Lecture6 Dental Anatomy Dr. Shatha Al-Salman
Maxillary central incisor
The maxillary central incisor, or first incisor, is the first tooth in the
maxilla to the right or left of the median line.
The crown length is as great as, or greater than, any of the other
anterior teeth excepting the mandibular canine, and its mesiodistal
width is greater at the cervix and contact areas than in any other
anterior tooth.
The maxillary central incisor is the most prominent tooth and
therefore the most noticeable in the dental arches. In general, they
are 2 in number.
Function: 1 - Biting, cutting, tearing 2 - Esthetic 3 - Phonetic
Labial Aspect: - 1 - The cervical third of the crown is semi-circular in outline. 2 - Its square crown appearance. 3 - The Mesio – incisal angle of this incisor approaches a right angle in the outline. 4 - Contact area with the other central incisor near the incisor edge. 5 - The disto-incisal angle is much more rounded than the mesio-incisal angle. 6 - The incisor edge outline is usually regular and straight. 7 - The root is a conical shape with a blunt or curvature apex. 8 - The length of the root is longer than the crown from 2---3 mm. 9 - Smooth and convex labial aspect. 10 - The labial aspect is slightly divided by two shallow vertical developmental grooves.
Mesial Aspect
1 - The crown is wedge–shaped or triangular. 2 - The labial outline from the crest of curvature to the incisal edge is slightly convex. 3 - Lingual outline is convex at the crest of curvature at the cingulum then it becomes concave at the mesial marginal ridge. 4 - The curvature of the cervical line on the mesial surface curves toward the incisal edge about one-third the length of the crown. 5 - The mesial surface is longer than the distal surface. 6 - The root may be outlined as a blunt cone from the points at which the crown joins the root labially and lingually to the apex.
Distal Aspect
The distal aspect is a practically similar outline to that of the mesial aspect there is one important difference the cervical curvature of the cementoenamel junction is less in extent than that on the mesial surface.
Maxillary lateral incisor
The maxillary lateral incisor supplements the central incisor in function, so the crowns bear a close resemblance. The lateral incisor is smaller in all dimension except root length.
Labial Aspect
1 - Lateral incisor has more curvature, with a rounded incisal ridge. 2 - Lateral incisor rounded incisal angle mesially and distally. And it is more rounded distally than the central incisor. 3 - The crown is smaller in all dimensions than the central incisor. 4 - Labial surface of the crown is more convex than that of the central incisor. 5 - This tooth is relatively narrow Mesio-distally about 2mm narrower than the central incisor. 6 - This tooth is shorter cervico-incisally. 7 - Root length is greater in proportion to the crown length of the central incisor. 8 - Contact point mesially at the junction of the middle third and incisal third while distally at the center of the middle third.
Lingual Aspect
- Mesial and distal marginal ridge are wall marked.
- The cingulum is usually prominent with a tendency toward deep development grooves with the lingual fossa.
- Lingual fossa is more concave.
- Tooth tapers toward the lingual.
- Developmental groove fin at the side of cingulum , usually on the distal side.
Distal Aspect
1 - Width of the crown distally appears thicker than on the mesial aspect from the marginal ridge to the labial face because of the placement of a crown on the arch. 2 - cervical line curvature is usually less in depth than in the mesial Aspect.
Incisal Aspect
1 - It is similar to that of the incisal aspect of the maxillary central incisor. 2 - All maxillary lateral incisor exhibits more convexity labially and lingually from the incisor aspect than maxillary central incisor.
