Maxillary Central Incisor - develops from 4 primary centers of
formation (lobes); 3 labial lobe and 1 lingual lobe - Widest
mesiodistal dimension; generally smooth MORPHOLOGY OF NEWLY ERUPTED
CENTRAL INCISOR presence of mamelons Two shallow developmental
depressions labially Perikymata fine horizontal lines on the crown
surface 2 basic forms: wide cervix and narrow cervix Variations:
short root, unusually long crown, shovel-shaped incisors
Contact Area Mesial- incisal 3rd, very near or approaching the
incisal angle Distal near the junction of the incisal and middle
3rd
Labial aspect Crown outline is trapezoidal Length of crown
usually greater than MD width Outline of crown: Mesial slightly
convex Distal outline more convex Mesioincisal angle = sharp ;
Distoincisal angle = more convex Incisal outline regular and
straight in MD direction Cervical outline: semi-circular with
curvature rootwise Root is cone-shaped, with a regularly blunt
apex; root is 2 or 3 mm more longer than crown Root axis line of
crown and root labially tends to parallel the mesial outline of the
crown and root
Lingual Aspect Crown outline is trapezoidal Smooth convexity at
the cervical 3rd, cingulum is located off centered towards distal
Bet. Mesial and distal marginal ridges is a shallow concavity, the
lingual fossa Shovel-shaped incisors incisors with deep lingual
dossa and prominent marginal ridges Linguoincisal edge is raised,
in level with MRs There are developmental grooves extending from
the cingulum to the lingual fossa Crown and root taper lingually
Root surface on lingual is narrower than labially
Mesial Aspect Crown is triangular or wedge-shaped Root axis
line bisect incisal ridge and root apex, Incisal ridge is in line
with center of the root Crest of curvature at the cervical 3rd
greatest labiolingual measurement CEJ curves incisally to a
noticeable degree than any of the tooth in the mouth Root is
cone-shaped, apex is usually bluntly rounded
Distal Aspect Similar to mesial; except crown is thicker toward
incisal 3rd Less curvature of CEJ Most teeth turned a little on
their root bases, in order to adapt to the curvature of the dental
arch, creating an illusion of greater thickness on the distal
Incisal Aspect Labial surface is relatively broad and flat
especially towards the incisal 3rd Cervical portion of crown is
convex, arc is described as broad Incisal ridge slope toward the
lingual Lingual outline tapers towards the cingulum Cingulum off
centered to the distal Prominent mesiolabial and distolabial line
angles Labiolingual calibration of the crown is more than two 3rds
as great as the MD calibration