ORAL ANATOMY
MANDIBULAR DENTITION
Mandibular incisors
4 in number
Have smaller MD dimension
Central is somewhat smaller than the lateral incisor
Teeth are similar in form
With smooth crown surfaces
Mamelons are worn of soon after eruption
Contact areas are near the incisal ridges mesially & distally
Show uniform development with few instances of anomalies or
malformations
The labial faces are inclined lingually so that the incisal ridges are
lingual to a line bisecting the root.
After normal wear,the incisal show a labial inclination (occlusion is
normal)
Incisal surface of maxillary incisors show lingual inclination
, Incisal planes of maxillary & mandibular incisors are parallel
Incisal planes of maxillary & mandibular incisors are parallel with each
other ftting each other during incising action.
Mandibular central incisor
Smallest permanent tooth
A little more than half the MD diameter than the maxillary central
incisor
Labiolingual dimension is about 1mm less
Root is very narrow mesiodistally and corresponds to the narrowness
of the crown
Root and crown are wide labiolingually
Length of the root is as great or if not greater than that of the maxillary
central incisor.
LABIAL ASPECT
Regular, tapering evenly from the relatively sharp incisal angles to
the root apex.
Incisal ridge is straight and at right angle to the long axis of the tooth.
, Mesial and distal outlines of the crown make a straight drop downward
from the incisal angles to the contact areas.
MCA & DCA- incisal to the junction of the incisal & middle 3rds.
M & D sides of the crown taper evenly from the contact area to the
narrow cervix.
ROOT
M & D root outlines are straight with the M&D outlines of the crown
down to the apical portion.
Apical 3rd of the root terminates in a small pointed taper, in most cases
curving distally.
Sometimes roots
Show few traces of developmental lines
Root is regular and convex
Labial face is smooth
With fattened surface at the incisal 3rd, middle 3rd is more convex,
narrowing down the convexity of the root at the cervical portion.
LINGUAL ASPECT
, Smooth with very slight concavity at the incisal 3rd between
insconspicuous marginal ridges
Some with marginal ridges that are prominent near the incisal edges
and more distinct lingual fossa
Becomes fat and then convex as progression is made from the incisal
3rd to the cervical 3rd.
No developmental lines mark the cingulum development at the
cervical 3rd
Shows very few developmental lines and grooves
The outlines and surfaces are regular and symmetrical
Mesial surface
Curvature labially & lingually above the cervical line is less than that
found on the maxillary incisors.
Labial outline
Straight above the cervical curvature, sloping rapidly from the contact
area to the incisal ridge.
Lingual outline
Straight line inclined labially for a short distance above the smooth
convexity of the cingulum, joining a concave line at the middle 3rd of
MANDIBULAR DENTITION
Mandibular incisors
4 in number
Have smaller MD dimension
Central is somewhat smaller than the lateral incisor
Teeth are similar in form
With smooth crown surfaces
Mamelons are worn of soon after eruption
Contact areas are near the incisal ridges mesially & distally
Show uniform development with few instances of anomalies or
malformations
The labial faces are inclined lingually so that the incisal ridges are
lingual to a line bisecting the root.
After normal wear,the incisal show a labial inclination (occlusion is
normal)
Incisal surface of maxillary incisors show lingual inclination
, Incisal planes of maxillary & mandibular incisors are parallel
Incisal planes of maxillary & mandibular incisors are parallel with each
other ftting each other during incising action.
Mandibular central incisor
Smallest permanent tooth
A little more than half the MD diameter than the maxillary central
incisor
Labiolingual dimension is about 1mm less
Root is very narrow mesiodistally and corresponds to the narrowness
of the crown
Root and crown are wide labiolingually
Length of the root is as great or if not greater than that of the maxillary
central incisor.
LABIAL ASPECT
Regular, tapering evenly from the relatively sharp incisal angles to
the root apex.
Incisal ridge is straight and at right angle to the long axis of the tooth.
, Mesial and distal outlines of the crown make a straight drop downward
from the incisal angles to the contact areas.
MCA & DCA- incisal to the junction of the incisal & middle 3rds.
M & D sides of the crown taper evenly from the contact area to the
narrow cervix.
ROOT
M & D root outlines are straight with the M&D outlines of the crown
down to the apical portion.
Apical 3rd of the root terminates in a small pointed taper, in most cases
curving distally.
Sometimes roots
Show few traces of developmental lines
Root is regular and convex
Labial face is smooth
With fattened surface at the incisal 3rd, middle 3rd is more convex,
narrowing down the convexity of the root at the cervical portion.
LINGUAL ASPECT
, Smooth with very slight concavity at the incisal 3rd between
insconspicuous marginal ridges
Some with marginal ridges that are prominent near the incisal edges
and more distinct lingual fossa
Becomes fat and then convex as progression is made from the incisal
3rd to the cervical 3rd.
No developmental lines mark the cingulum development at the
cervical 3rd
Shows very few developmental lines and grooves
The outlines and surfaces are regular and symmetrical
Mesial surface
Curvature labially & lingually above the cervical line is less than that
found on the maxillary incisors.
Labial outline
Straight above the cervical curvature, sloping rapidly from the contact
area to the incisal ridge.
Lingual outline
Straight line inclined labially for a short distance above the smooth
convexity of the cingulum, joining a concave line at the middle 3rd of
