Maxillary Anterior Teeth PDF 2023/2024

2023\2024 Dental Anatomy Dr.Faten S.M Maxillary Anterior Teeth\ Lec4 The PERMANENT Maxillary Incisors The maxillary incisors are four in number. The maxillary central incisors are centered in the maxilla, one on either side of the media...

2023\2024 Dental Anatomy Dr.Faten S.M Maxillary Anterior Teeth\ Lec4 The PERMANENT Maxillary Incisors The maxillary incisors are four in number. The maxillary central incisors are centered in the maxilla, one on either side of the median line, with the mesial surface of each in contact with the mesial surface of the other. The right and left maxillary lateral incisors are distal to the central incisors. The maxillary central incisor is larger than the lateral incisor. These teeth supplement each other in function, and they are similar anatomically. The incisors are cutting teeth. Their major function is cut food material during the process of mastication. These teeth have incisal edges rather than cusps such as are found on the canines and posterior teeth. Maxillary Central Incisor Eruption: 7 to 8 years Root completed: 10 years The maxillary central incisor is the widest mesiodistally of any of the anterior teeth. When this tooth is newly erupted into the mouth, the incisal edges have three rounded features called mamelons. Mamelons disappear with time as the enamel wears away by friction. 1 2023\2024 Dental Anatomy Dr.Faten S.M Labial Aspect: 1. It is less convex than the maxillary lateral incisor or canine, which gives the central incisor a square or rectangular appearance. 2. The mesial outline of the crown is only slightly convex, with the crest of curvature (representing the contact area) approaching the mesioincisal angle. 3. The distal outline of the crown is more convex than the mesial outline, the crest of curvature being higher toward the cervical line. 4. The mesioincisal angle is sharper than the distal incisal angle. After the mammelons are worn away, the incisal edge of the maxillary central incisor is straight mesiodistally. 5. The cervical outline of the crown follows a semicircular direction with even curvature toward the root. 6. The root of the central incisor from the labial aspect is cone-shaped, in most instances with a relatively blunt apex, the outline mesially and distally being regular. The root is usually 2 or 3 mm longer than the crown. Lingual Aspect: 1. The surface form of the maxillary central incisor is more irregular. 2. The largest part of the middle and incisal portions of the lingual area is concave this shallow concavity is called the lingual fossa. The concavity is bordered by mesial and distal marginal ridges, the lingual portion of the incisal ridge, and the convexity toward the root which is called the cingulum. The crown and root taper lingually, making the lingual portion of the root narrower than the labial portion. 2 2023\2024 Dental Anatomy Dr.Faten S.M Mesial Aspect: 1. The crown is triangular, with the base of the triangle at the cervix and the apex at the incisal ridge. 2. The incisal ridge of the crown is on a line with the center of the root. 3. Labially and lingually, immediately coronal to the cervical line are the crests of curvature of these surfaces. These crests of contour give the crown its greatest labiolingual measurement. 4. The labial outline of the crown from the crest of curvature to the incisal ridge is very slightly convex. 5. The lingual outline is convex at the point where it joins the crest of curvature at the cingulum; it then becomes concave at the mesial marginal ridge, and it becomes slightly convex again at the linguoincisal ridge and the incisal edge. 6. The cervical line curves incisally to a noticeable degree. The root of this tooth from the mesial aspect is cone-shaped, and the apex of the root is usually bluntly rounded. Distal Aspect: There is little difference between the distal and mesial outlines of this tooth. The curvature of the cervical line outlining the cementoenamel junction is less in extent on the distal than on the mesial surfaces. 3 2023\2024 Dental Anatomy Dr.Faten S.M Incisal Aspect: 1. The labial surface appears broad and flat. 2. The outline of the lingual portion tapers lingually toward the cingulum. The cingulum of the crown makes up the cervical portion of the lingual surface. 3. The crown conforms to a triangular outline reflected by the outline of the root cross section at the cervix. The distance between the mesioincisal angle to the cingulum is slightly longer than the distance between the distoincisal angle to the cingulum. 4. The incisal ridge may be seen clearly, and a differentiation between the incisal edge and the remainder of the incisal ridge, with its slope toward the lingual, is easily distinguished. Anatomical Variations of Maxillary Central Incisor -Large crown -Small root Maxillary Lateral Incisor: The maxillary lateral incisor supplements the central incisor in function; the crown bear a close resemblance. The lateral incisor is smaller in all dimension except root length. Eruption: 8-9 years Root complete: 11years 4 2023\2024 Dental Anatomy Dr.Faten S.M Principal identifying features of maxillary lateral incisor: 1. Crown is more rounded, shorter and narrower mesio-distally than the maxillary central incisor. 2. Mesioincisal angle is rounded and distoincisal angle is more rounded. 3. Single root with tapered distally curved pointed apex. 4. lingual fossa is more concave than that of maxillary central incisor. Labial Aspect: 1. The labial surface of crown is convex than that of the maxillary central incisor. 2. The crown is smaller in all dimension as compared with the maxillary central incisor. 3. The mesial outline of the crown resembles that of the central incisor, with a more rounded mesioincisal angle. The crest of contour mesially is usually at the point of junction of the middle and incisal third. 4. The distal outline of the crown from the labial aspect differs somewhat from that of the central incisor. The distal outline is more rounded, and the crest of contour is more cervical. 5. The root length is greater in proportion to its crown length of the crown. 5 2023\2024 Dental Anatomy Dr.Faten S.M Lingual Aspect: 1. Mesial and distal marginal ridges and the lingual portion of the incisal ridge are marked with more concave lingual fossa. 2. The cingulum is usually prominent. Mesial Aspect: The mesial aspect is similar to that of central incisor except that: 1. The root appears longer. 2. Crown labiolingually is narrower. 3. Curvature of the cervical line is less in depth. Distal Aspect: 1. The distal aspect similar to mesial aspect except that; 2. Curvature of the cervical line is less in depth. 6 2023\2024 Dental Anatomy Dr.Faten S.M Incisal Aspect: The incisal aspect of this tooth sometimes resembles that of central incisor, or it may resemble that of a small canine 1. The cingulum, may be large; the labiolingual dimension may be greater in comparison with the mesiodistal dimension. If these variations are present, the tooth has a marked resemblance to a small canine. 2. All maxillary lateral incisors exhibit more convexity labially and lingually from the incisal aspect than maxillary central incisors. Anatomical Variations of maxillary latral incisor -Peg shape -Congenital missing 7