MANDIBULAR LATERAL INCISOR INTRODUCTION Lateral incisors generally appear in the oral cavity after central incisors. Lateral incisors usually erupts during the seventh year of life . Roots complete: 9 – 10 years FDI SYSTEM (Federation Dentaire Internationalae)- Mandibular RIGHT lateral incisor- 42 Mandibular LEFT lateral incisor- 32 UNIVERSAL SYSTEM- Mandibular RIGHT lateral incisor- 26 Mandibular LEFT lateral incisor- 23 Zsigmondy-palmar system Mandibular RIGHT central incisor- 2 Mandibular LEFT central incisor- 2 ARCH TRAITS Lingual fossa are less pronounced on mandibular incisors. Mandibular lateral incisors have roots that are more triangular in cross section. Labio-lingual diameter is wider than mesio-distal diameter. CLASS TRAITS- Crown shapes are rectangular, longer inciso-gingivally than mesio-distally. Mesial & distal marginal ridge converge toward the lingual cingulum. SET TRAIT There are depression or perikymata on the labial surface of the crown of the incisors. Mammelons are seen on the incisal edge of newly erupted incisors. Cervical ridges of anterior permanant teeth are prominent than primary teeth. TYPE TRAIT Lateral incisors have distal proximal contact more apical than the mesial contact. Lateral incisors have disto-incisal angle more rounded than the mesio-incisal angle. Labial Aspect Crown is trapezoidal from labial aspect. Mesial outline is almost straight in line with mesial outline of root. Distal outline is straight near cervix and become slightly convex as it reaches distoincisal angle. Distoincisal angle more rounded than mesioincisal angle Incisal outline formed by incisal ridge is straight but has tendency to slope cervically in distal direction. Cervical line is curved apically. Crown is not bilaterally symmetrical Distal half is slightly larger. lingual aspect Its shape is trapezoidal like labial surface. Crown tapers lingually making lingual surface narrower than labial surface. Shallow lingual fossa Lingual surface is smooth devioid of developmental grooves, and is convex near cingulum. Distal surface bulges from the incisal view incisal aspect It is oval labiolingually. Labiolingual dimension is greater than mesiodistal. Incisal ridge is at an angle to the line bisecting the tooth labiolingually rather than being perpendicular. Slightly twisted on its root base from this aspect. Cingulum twisted (off-center) to the distal mesial aspect Mesial aspect is triangular Labial outline is convex near cervical line Lingual outline is straight in incisal 3rd Incisal edge lingual to root axis line CEJ is curved more on the mesial than the distal Mesial contact area is at incisal 3rd of crown Mesial surface is longer than distal surface

2. Introduction
Lateral incisors generally appear in the
oral cavity after central incisors.
Lateral incisors usually erupts during the
seventh year of life .
 Roots complete: 9 – 10 years

3. CHRONOLOGY
 First evidence of
Calcification
3 to 4 month
 Enamel completed 4 to 5 years
 Eruption 7-8 years
 Root completed 10 years

4. MEASUREMENTS
 CERVICOINCISAL LENGTH OF CROWN 9.5mm
 LENGTH OF ROOT 14mm
 MESIODISTAL DIAMETER OF CROWN 5.5mm
 MESIODISTAL DIAMETER OF CROWN AT
CERVIX
4 mm
 LABIOLINGUAL DIAMETER OF CROWN 6.5mm
 LABIOLINGUAL DIAMETER OF CROWN AT
CERVIX
5.8mm
 CURVATURE OF CERVICAL LINE-MESIAL 3mm
 CURVATURE OF CERVICAL LINE-DISTAL 2mm

5. TOOTH NUMBERING
SYSTEM
 FDI SYSTEM (Federation Dentaire
Internationalae)-
 Mandibular RIGHT lateral incisor- 42
 Mandibular LEFT lateral incisor- 32

6.  UNIVERSAL SYSTEM-
 Mandibular RIGHT lateral incisor- 26
 Mandibular LEFT lateral incisor- 23

7. Zsigmondy-palmar system
Mandibular RIGHT central incisor-
2
Mandibular LEFT central incisor-
2

8.  ARCH TRAITS
 Lingual fossa are less pronounced on
mandibular incisors.
 Mandibular lateral incisors have
roots that are more triangular in cross
section.
 Labio-lingual diameter is wider than
mesio-distal diameter.

9. CLASS TRAITS-
Crown shapes are rectangular,
longer inciso-gingivally than
mesio-distally.
Mesial & distal marginal ridge
converge toward the lingual
cingulum.

10. SET TRAIT
There are depression or perikymata
on the labial surface of the crown of
the incisors.
Mammelons are seen on the incisal
edge of newly erupted incisors.
Cervical ridges of anterior
permanant teeth are prominent than
primary teeth.

11.  TYPE TRAIT
 Lateral incisors have distal proximal
contact more apical than the mesial
contact.
 Lateral incisors have disto-incisal
angle more rounded than the mesio-
incisal angle.

12. Morphology
Labial Aspect
 Crown is trapezoidal from labial aspect.
 Mesial outline is almost straight in line with mesial
outline of root.
 Distal outline is straight near cervix and become
slightly convex as it reaches distoincisal angle.
 Distoincisal angle more rounded than mesioincisal
angle
 Incisal outline formed by incisal ridge is straight but
has tendency to slope cervically in distal direction.
 Cervical line is curved apically.
 Crown is not bilaterally symmetrical
 Distal half is slightly larger.

14. Lingual Aspect
 Its shape is trapezoidal like labial surface.
 Crown tapers lingually making lingual surface
narrower than labial surface.
 Shallow lingual fossa
 Lingual surface is smooth devioid of
developmental grooves, and is convex near
cingulum.
 Distal surface bulges from the incisal view

16. Incisal Aspect
 It is oval labiolingually.
 Labiolingual dimension is greater than
mesiodistal.
 Incisal ridge is at an angle to the line bisecting
the tooth labiolingually rather than being
perpendicular.
 Slightly twisted on its root base from this aspect.
 Cingulum twisted (off-center) to the distal

18. Mesial Aspect
 Mesial aspect is triangular
 Labial outline is convex near cervical line
 Lingual outline is straight in incisal 3rd
 Incisal edge lingual to root axis line
 CEJ is curved more on the mesial than the distal
 Mesial contact area is at incisal 3rd of crown
 Mesial surface is longer than distal surface

20. Distal View
 Distal aspect is similar to mesial aspect
except
 Cervical line on distal surface is less curved
 Distal contact area is within incisal 3rd

21. Contact Areas
 Mesial and distal contact areas in incisal
1/3
Root Anatomy
 Mesial and distal root
depressions
 Apex may curve slightly to
the distal

22. Variations
 2 canals in single root
 Long root
 Small size of tooth
 Bifurcation of root into labial and lingual
divisions

25. ENDODONTIC ANATOMY
 The pulp chamber is small & flat
mesiodistally
 The access opening of mand. Incisor is a
long oval in shape with its greatest
dimensions oriented incisogingivally.

26. Thank you