The maxillary central incisor is the most prominent tooth in the dental arch. It has a rectangular shape that is wider from side to side than front to back. The crown sits directly over the root with no portion of the root visible. There can be variations in the depth of the lingual fossa and amount of convergence of the mesial and distal surfaces. Rare anomalies include Hutchinson's incisors which have a screwdriver shape, talon cusps on the lingual surface, and extra supernumerary teeth between the central incisors.

1. Maxillary Incisors
Principal Identifying Features
 The maxillary central incisor is the tooth in each maxillary
quadrant of the permanent dentition which is on each side of the
midline.
 Normally, the max central incisors are the most prominent teeth
in the oral cavity and so they are most noticeable in the dental
arch, hence they contribute a focal point for the eye of the
observer. In general, the labial outline of the crown conform to
the general outline of the face.
 The max central incisor (MCI) is the widest tooth mesio-distally
(MD), the labial surface is less convex than lateral incisor and
canine that give the tooth a rectangular appearance. It is the first
tooth from the midline. It has a slightly straight incisal edge.
Central Incisor
Chronology
Appearance of enamel organ 5 m.i.u
First evidence of calcification 3 - 4 months.
Crown completed 4 - 5 years.
Eruption 7-8 y
Root completion 10-11 y
Labial aspect
 Geometric out line

2. Trapezoid with the smallest side at the cervical line and the larger
side at the incisal ridge, where the central incisor
contacts its neighbors.
 The mesial outline
The crown is slightly convex.
 The distal outline
The crown is more convex than the mesial outline.
 Contact areas
Mesially: approaching the mesio-incisal angle.
Distally: higher towards the cervical line near the
junction between middle and incisal thirds.
 Incisal angles
The mesio- incisal angle is nearly a right angle “sharp”
disto-incisal angle is rounded.
 The incisal outline
Incisal outline of newly erupted tooth usually reveals mamelons,
they are usually three in number, of which the central mamelon is
the smallest.
A time after eruption the incisal ridge undergoes attrition, the
incisal edge is straight and perpendicular to the longitudinal axis of
the tooth.
 Cervical line
Semicircle with the curvature root-wise.
 Surface description
The labial surface of this tooth is smoothly convex with the
maximum convexity at the cervical third, referred to as cervical
ridge. The labial surface is marked by 2 faint or shallow vertical
grooves which divide the labial surface into 3 portions or lobes.

3.  The root
Root is cone shaped with blunt apex. A line drawn through the
center of the root and crown of the maxillary central incisor tends
to parallel the mesial outline of the crown and root.
Lingual Aspect
 It represent elevations and depressions but the
general outline is the reverse picture of the labial
surface.
 The proximal sides of the crown and root converge
lingually, making the lingual surface of the tooth
narrower than the labial surface to accommodate the
horse-shoe shaped alveolar ridge, where the outer
surface of the ridge is wider than the inner surface
that is called lingual convergence.
 The root is generally triangular with rounded angles.
 Cervical line is similar to that of labial.
 Morphologically , lingual surface shows convexities and concavity:
 The cingulum: smooth round large convexity present at the
cervical third immediately below the cervical line.
 The mesial and distal marginal ridges: they extend from the
cingulum mesial and distally to the incisal ridge.
 Incisal ridge (linguincisal edge): elevation (being on a level
with the marginal ridges) making the thickness of incisal
edge from the lingual surface.
 Lingual fossa: lingual depression between the marginal
ridges and extend from the cingulum to the incisal ridge. It
has M-shape and occupying the incisal two third.
Mesial Aspect
 The mesial surface of the crown is wedge-shaped or
triangular with the base of the triangular at the cervix and
the apex at the incisal ridge. This allows the tooth to be
forced easily through the food material.

4.  The labial outline of the crown is slightly convex with the crest of
curvature at the cervical ridge.
 The lingual outline is convex at the region of the cingulum. Then
it becomes concave as it outlines the mesial marginal ridge and
becomes slightly convex again as it outlines the linguo-incisal
ridge.
 The cervical line is concave root-wise.
 The incisal ridge is with the line bisecting the tooth.
 The root is cone shaped with a blunt apex; the labial outline is
straighter than the lingual outline.
 The mesial surface is smooth except for a concavity represents the
contact area.
Distal Aspect
 It is similar in oultine to the mesial surface.
 But the curvature of the cervical line is less in
curvature then from the mesial surface.
 The distal contact area is more cervical than
mesial one.
 Incisal edge distally is broader than mesially so the crown appear
thicker.
Incisal Aspect
 The incisal ridge is seen to be centered over the root.
 The crown superposes over the root entirely so that nothing of the
root is visible i.e. the crown and the root base on the same long
axis.
 The crown outline is roughly triangular with somewhat curved
labial outline that form the base of the triangular while the
proximal sides converge toward the
cingulum.

5.  Crown is wider MD than LL. Labial outline is broad, flat
compared with the lingual surface. Cingulum is located off center
toward the distal side. So, MMR is longer than DMR. Fossa is seen
as a concavity between the two MR and cingulum.
 Note that
The incisal ridge is that portion of the crown which makes up the
complete incisal portion. When an incisor is newly erupted, the incisal
portion is rounded and merges with the mesioincisal and distoincisal
angles and the labial and lingual surfaces. This ridge portion of the
crown is called the incisal ridge. The term edge implies an angle
formed by the merging of two flat surfaces. Therefore, an incisal edge
does not exist on an incisor until occlusal wear has created a flattened
surface linguo-incisally, which surface forms an angle with the labial
surface. The incisal edge is formed by the junction of the linguoincisal
surface, (sometimes called the incisal surface), and the labial surface.
Variations and anomalies
a) Of all the crown surfaces, the lingual exhibits the greatest
variation. As previously mentioned, a pit may occasionally be
present, and the depth of the fossa has a considerable range.
b) When viewed from the labial or lingual aspects, a wide variation
occurs in the amount of convergence of the mesial and distal
surfaces toward the cervical. When there is little convergence, the

6. outline of the surface resembles a rectangle, but when great
convergence is present, it is more nearly triangular.
c) Root length may vary considerably, but deflections of the root are
relatively rare. When the root is exceptionally short, in conjunction
with an abnormal contour of the crown, this anomalous condition is
referred to as dwarfed root, and the lack of root support may
endanger the tooth's longevity in the mouth.
d) Hutchinson's incisors: Congenital syphilis sometimes manifests
itself in the central incisor by producing a screwdriver shaped
crown, when it is viewed from the labial aspect.
e) Talon cusp: A large accessory cusp on the lingual surface of
maxillary incisors characterizes this anomaly. Involved teeth often
bear a resemblance to a Phillips screwdriver.
f) The alveolar bone between the roots of the two central incisors is
occasionally the site of supernumerary teeth or extra teeth,
known as mesiodens. Cysts may also be found in this area.