Mandibular Incisors
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Transcript of Mandibular Incisors
Mandibular IncisorsMandibular Incisors
Dr. Syed Sadatullah Dr. Syed SadatullahIbnsina National CollegeIbnsina National College
JeddahJeddah
Introduction
Mandibular incisors are four in number
Mandibular central incisor and lateral are similar in anatomy and complement each other in function
They are smaller than the maxillary incisors
Mandibular central incisor erupts between the age of 6 and 7
Mandibular lateral incisor erupts between the age of 6 and 8
Labial aspect Labial surface of mandibular central incisor is
very small. It is the narrowest tooth mesiodistally of all the permanent teeth
It is bilaterally symmetrical
It is the only incisor where both mesioincisal and distoincisal angles are sharp and at right angles
The labial surface is inclined lingually
Labial aspect
Lingual aspect The lingual aspect is concave from the incisal
edge to the cervical line
Cingulum is smooth and barely visible
The surface is smooth and devoid of any grooves. No other tooth in the mouth, except the mandibular lateral incisor, shows so few developmental lines and grooves.
Lingual aspect
Mesial aspect The labial outline is almost straight, except near
cervical third where it is convex
The lingual margin is ‘S’ shaped
The cervical line on the mesial and distal surface is convex incisally
Mesial aspect
Distalaspect Distal surface is very similar to the mesial
surface. The cervical line is less curved.
Distal aspect
Incisal aspect This aspect illustrates the bilateral symmetry of
this tooth.
The labiolingual diameter is greater than mesiodistal diameter.
Newly erupted teeth show mamelons which wear off upon mastication
Incisal aspect
RootThe root is single and straight.
The deflection of the root if present is on the labial or
distal side.
3.0 2.0 5.3 6.0 3.5
5.0 12.5 9.0
Curvature of Cervical Line
M D
Labiolingual
Diameter at
Cervical Line
Labiolingual
Diameter at
Crest of Curvature
Mesiodistal
Diameter at
Cervical Line
Mesiodistal
Diameter at
Contact Area
Root
Length
Crown Length
Average Dimensions in millimeters
Mandibular Lateral Incisor Mandibular lateral incisor is slightly wider
mesiodistally
The concavity in the lingual aspect is slightly more when compared to mandibular central incisor
The cervical portion of the lingual aspect is narrower while the incisal portion is wider. This gives the crown a more or less a fan shaped appearance
The incisal edge follows the mandibular arch, giving the crown a slightly twisted appearance on its root
Labial aspect
Lingual aspect
Mesial aspectDistal aspect
Incisal aspect