By

Dr. Abhishek Solanki

INTRODUCTION Second tooth from the midline in each lower quadrant

Shares a mesial contact area with the central incisor.

Mandibular lateral incisor is slightly wider mesiodistally

slightly larger in all respects than the mandibularcentral incisor

complements the central in function.

The distal contact is with the deciduous mandibularcanine until that tooth's exfoliation and then contact isshared with the permanent canine.

Labial aspect Lingual aspect

Mesial aspectDistal aspect

Incisal aspect

TOOTH NUMBERING SYSTEMUNIVERSAL SYSTEM - 23,26

ZSIGMONDY / PALMER - 2 2

FDI SYSTEM - 32, 42

CHRONOLOGY

First evidence of calcification 3-4 months

Crown completion 4-5 years

Eruption 7-8 years

Root completion 10 years

DIMENSIONS

Cervico incisal Length of crown

Length of the root

Mesiodistal diameter of crown

Mesiodistal diameter of crown at

cervix

Labio or Buccolingualdiameter of

Crown Cervix

Curvature of cervical line –

Mesial Distal

9.5 mm 14.0 mm 5.5 mm 4.0mm 6.5 mm 5.8 mm 3 mm 2 mm

Labial Aspect Incisal margin may slope slightly gingivally toward distal,

which results in a distoincisal angle that is more rounded

than same angle of central incisor

This feature creates a slightly shorter distal margin, when

compared to mesial outline

Contact area on distal is more cervically located than on

the mesial, thus creating a more cervically located height

of contour on distal outline

Both heights of contour are still in incisal third

Lingual Aspect Lingual outlines are similar to those of labial aspect

Structures of lingual surface are similar to their

counterparts on the central incisor except cingulum is

more offset to distal, and as a result curvature of

cervical line is also offset distally

Mand. Lat. InciosorMand. Central Incisor

M D D M

• Concavity in lingual aspect is slightly more when

compared to mandibular central incisor

• MMR > DMR

Lingual fossa more concave

Mesial & Distal Aspects Two surfaces are similar to their counterparts on central

incisor, with a few minor exceptions.

Lateral's distal surface is slightly shorter inciso-cervically

than mesial surface.

Both cervical line curvatures are slightly less than their

counterparts in the central.

MESIAL DISTAL

Mesial cervical line shows greater incisal curvature than

does the distal

At distal contact area, height of contour is more

cervically located than on mesial

In incisal third, distal contact area is very near to junction

of incisal & middle thirds & is most cervically located of

any mandibular incisor contact

Incisal Aspect Incisal edge is not straight mesiodistally, as it is in

central, rather it curves toward lingual in its distal portion

Lingual contour (cingulum) appears displaced toward

distal. These factors give crown the appearance of being

slightly twisted on its root

Best identifying features, when differentiating this tooth

from central incisor

M D

Root Root length is normally a little greater than in central

incisor

Root is also slightly thicker and wider

Root concavities may be found on the mesial and distal

root surfaces, and if present, concavity in distal is usually

more pronounced

Variations and Anomalies: Anomalies are rare, but occasionally a bifurcated root is

found

References CONCISE DENTAL ANATOMY & MORPHOLOGY :

JAMES L FULLER

DENTAL ANATOMY, PHYSIOLOGY & OCCLUSION:

WHEELER’S

TEXTBOOK OF DENTAL ANATOMY, PHYSIOLOGY &

OCCLUSION: RASHMI GS (PHULARI)

INTERNET