Maxillary central incisor is the first tooth from the midline and so is the tooth with most prominent effect on a person's smile. This is called as the incisal dominance. The tooth number of permanent maxillary central incisor in FDI system is 1 1 and 2 1. In universal system is 8 and 9 and in Zygmunti-Palmer system the tooth number for right and left is 1 with different brackets according to the quadrant. The function of maxillary central incisor is cutting. The tooth develops from four developmental lobes. They are mesial, labial, distal and lingual. The mesial, labial and distal lobes make the labial aspect of the crown and the incisal ridge whereas the lingual lobe is less developed and makes the cingulum. Since the incisal ridge is found by three lobes, three protuberances are seen on it in newly erupted incisor which are known as mammulons. With continuous use, these mammulons wear off and are not seen in adults. Mammalones are not present in deciduous incisors. The age of eruption of maxillary central incisor is 7 to 8 years. Now let us see its measurements. The cervico-incisor length or the crown length is 10.5 mm and the root length is 13 mm. The mesiodistal diameter of the crown which is measured at the contact areas is 8.5 mm and at cervix or at root junction is 7 mm. From the proximal aspect, the labiolingual diameter of crown measured at the level of cingulum is 7 mm and at cervix is 6 mm. The curvature of the cervical line is 3.5 mm on mesial side and 2.5 mm on the distal side. The morphology of teeth is studied under 5 aspects. Let's start with the first aspect, the labial aspect or the side of the tooth which is towards the lips. The outline form of the crown is trapezoidal with the longer of the two parallel sides towards the incisal ridge and shorter side towards the cervix. The maxillary central incisor has a horizontal incisal surface which ends at two angles. The sharp mesioincisal angle and the rounded distoincisal angle. The mesial contact area by which the maxillary central incisor makes contact with the other maxillary central incisor is at the incisal third. The distal contact area by which the maxillary central incisor contacts the lateral incisor is at the junction of the incisal line middle third. The distal outline of the tooth extending from the disto-incisal angle to the cervical line is more convex than the mesial outline which extends from the meso-incisal angle to the cervix. The cervical line is convex and the convexity is towards the root. The surface of the crown from the labial aspect is smooth and convex, except for slight mesial and distal developmental depressions, which are formed by the areas between developmental lobes. The root from the labial aspect appears smooth, convex and tapering towards the apex. Now palatal aspect, or the side towards the palate. As the palatal surface is narrower than the labial surface, all the features of the outline form from the labial aspect remain same in the lingual aspect as well, although the crown surface from the lingual aspect is very different. The lingual surface has three ridges. One incisal ridge, which runs horizontally between the mesioincisal angle and the distoincisal angle. Two marginal ridges which run along the mesial and distal margins. Mesial marginal ridge runs from the mesioincisal angle to the cingulum and distal marginal ridge which runs from the distoincisal angle to the cingulum. A large convexity called cingulum is present in the cervical third. In the middle of these ridges and cingulum is a smooth concavity called the lingual fossa. The lingual fossa in maxillary central incisor is said to be of W shape. This is because of the intrusion of cingulum into the cervical border of the lingual fossa. The root appears smooth, convex and tapering. Coming to the proximal aspects, the mesial aspect. From the mesial aspect, the crown is triangular or wedge shaped with its base at the cervix. The incisal ridge lies at the midline axis of the tooth. The labial outline is convex with its maximum convexity or the height of contour at the level of cingulum in the cervical third. The lingual surface is more complex. It is convex in the cervical third due to the cingulum, concave in the middle third due to the lingual fossa and then convex in the incisal third due to the incisal ridge. The cervical line is convex and the convexity is towards the crown. The root is smooth, convex and tapering towards the apex. Coming to the other proximal aspect, the distal aspect. The distal aspect is exactly the same as that of the mesial aspect. Lastly, the incisal aspect. As with all permanent teeth, no part of the root is visible from the incisal aspect. The crown is broader mesio-distally than labio-lingually. The labial outline is smooth and convex. The lingual outline is narrower showing the lingual convergence which is a feature of all permanent anteriors. The incisal ridge runs horizontally. Some clinical considerations. Shovel-shaped incisors are commonly seen in mongoloid race. These incisors have prominent marginal ridges which make their lingual surface very concave. Developmental anomalies like talon cusp, fusion, gemination, and dense invaginatus are more common in maxillary central incisors. Due to their location, maxillary central incisors are the teeth most prone to trauma. And screwdriver-shaped incisors or Hutchinson's incisor is the characteristic clinical feature seen in patients with congenital syphilis. It mostly forms due to the developmental failure of the middle lobe. This makes the tooth rhomboidal with the shorter side towards the incisal ridge like the blade of a screwdriver. Sometimes a small notch can be seen in the middle of the incisal ridge.