This document provides information about the anatomy and chronology of permanent maxillary central incisors. It begins by listing the learning objectives, which are to memorize the chronology, describe the aspects, and describe the pulp cavity. It then provides details about the chronology, describing when enamel formation, calcification, crown completion, eruption, and root completion occur. The rest of the document describes the anatomy of the tooth from the labial, lingual, mesial, distal, and incisal aspects. It notes geometric outlines, contact areas, ridges, depressions, and other features of each surface. It also describes the shape of the root and pulp cavity.

1. Dr. Khaled El-Haddad
k.elhaddad@qu.edu.sa

2. By the end of this lecture, the student should be able to:
1- Memorize the chronology of permanent maxillary central incisors
2- Describe the different aspects of permanent maxillary central incisor.
3- Describe the pulp cavity of the permanent maxillary central incisor.
‫ل‬ُ‫ق‬َ‫و‬
ِّ
‫ب‬َّ‫ر‬
‫ا‬ً‫م‬ْ‫ل‬ِ‫ع‬ ‫ي‬ِ‫ن‬ْ‫د‬ ِ
‫ز‬

3. General information about the incisors
Types Maxillary central and lateral
Mandibular central and lateral
Numbers 8 in total - 4 maxillary and 4 mandibular
Surfaces Labial, lingual, mesial, distal, incisal
Functions
Cutting food, Pronunciation of letters, Esthetics (especially supporting lips)

4. Maxillary central incisors

5. Universal system?
Write the number of maxillary central incisors by the 3
numbering systems?
Right central incisor Rt Lt
Left central incisor
8 9
Palmer system? 1 1
2 digit system? 11 21

6. 6-7 y
Enamel organ appearance:
Chronology
5 m.i.u.
Beginning of calcification 3-4 M
m.i.u. = Months Intra-Uterine
m= Months (after birth)
Crown completed 4-5 y.
y= years
Eruption 7-8 y.
Root completed 10 y.

7. There are 2 Upper (maxillary) central incisors
The central incisor contacts the lateral incisor distally
And contacts the central incisor of the other side mesially

8. General rules in description
1- The directions of the surfaces are inverted from the right
tooth an its corresponding left one.
Example: In the right central incisor, in the labial aspect:
* The mesial side is located in the left side of the patient (right in this photo)
* The distal side is located in the right of the patient (left in this photo)
If we studied the left central incisor, the directions are inverted
Same rule is followed in the study of all aspects
Rt Lt
Distal
Mesial
Mesial
Distal

9. General rules in description
Labial Lingual
2- The directions are also inverted between (labial and lingual)
Example: In the right central incisor, in the labial aspect:
* The mesial side is located in the left side of the patient (right in this photo)
* The distal side is located in the right side of the patient (left in this photo)
If we studied the lingual aspect of the same tooth (right central incisor), the
mesial side will be the opposite
Same rule is followed in the study of (mesial and distal aspects)
Distal
Mesial
Mesial
Distal

10. Apply the rule number 2
In the right central incisor, in the mesial aspect:
* The lingual side is located in the left side of the patient (right in this photo)
* The labial side is located in the right side of the patient (left in this photo)
If we studied the distal aspect of the right central incisor, the directions are
inverted
Labial
Lingual
Lingual
Labial
Mesial Distal

11. Central incisor from all aspects (surfaces)
(we will study the right central incisor)
Labial Lingual Mesial Distal
Incisal

12. https://www.dentaldecks.com/wp-content/public/docs/DAO%20card%20151%20back%20for%20web.pdf

13. Labial aspect
I- Crown:
A) geometric outline:
Trapezoid (‫)شبهِّمنحرف‬
(short side cervical /long side incisal)
M
D What is the trapezoid?
4-sided shape
With 2 parallel &uneven sides
And 2 even & unparalleled sides

14. Labial aspect
B) outlines:
1- Cervical line: Convex rootwise
2- Mesial outline: Straight slightly convex
Contact area: (Incisal third)
3- Distal outline: More convex
Contact area: Just cervical to the junction of incisal and middle thirds
4- Incisal:
* Mamelons seen in newly erupted incisors
* Incisal edge is straight and perpendicular to midline
*Mesial angle sharp &distal rounded
1
2
3
Mesial angle
Distal angle
Mesial
contact area
Distal
contact area

15. Labial aspect
C) surface:
Elevations: Cervical ridge
depressions:
Shallow mesiolabial &distolabial developmental grooves
Reaching the middle third
II- root:-
-Outline: Conical
-Surface: Smooth & convex
-Apex: Blunt & centered
These symmetric criteria of the root are present
in this tooth and in lower second premolars
Thus, their extraction easier than other teeth

16. Lingual aspect
I- Crown
A) geometric outline: Same as labial (with lingual convergence)
Lingual convergence:
The narrowing of the mesiodistal dimension from labial to lingual

17. Lingual aspect
B) outlines: Same as labial (with inverted directions as discussed before)
C) surface:
*Elevations:
Cingulum
marginal ridges
incisal ridge
*Depressions: lingual fossa
Cingulum
II- root:- Same as labial but narrower
Incisal ridge
Mesial marginal ridge
Distal marginal ridge
The lingual fossa
gives the tooth
the shovel shape

18. Mesial aspect
B) outlines:
*Cervical line: Concave rootwise
*Labial outline :
Convex cervical 1/3 (cervical ridge)
Then less convex to the incisal edge
*Lingual outline :
Convex (cingulum)
Concave (lingual fossa)
Convex (incisal ridge)
*incisal: Midline
Cervical line
Cervical ridge
Cingulum
Lingual fossa
Incisal ridge
I- Crown
A) geometric outline: Triangle (base is cervical)
Less convex

19. Mesial aspect
C) surface:
Contact area: Incisal 1/3
II- root:-
Outline: Conical
Surface: Smooth and convex
Apex: Blunt and centered

20. Distal aspect
I- Crown:
A) geometric outline: As mesial
B) outlines: As mesial aspect except:
*Cervical line: Less curved
C) surface:
Contact area:
Just cervical to the junction of incisal and middle thirds
II- root:- As mesial
Mesial
Distal
Less curved
Contact area

21. Incisal aspect
A) geometric outline:
Triangular (base labially and apex lingyally)
B) Incisal edge: Centered labio-lingually
C) Cingulum:
Slightly shifted to distal
Labial
Lingual

22. Pulp cavity
Three Pulp horns
Single root canal:
Cross section: Triangular
(base labially and apex lingually)

23. Apply your knowledge

24. **
Evaluate the surface
Evaluate this work

25. Evaluate this work
**
Evaluate the contact

26. **
Evaluate the contact

27. **
Evaluate the incisal angles

28. **
Evaluate the incisal edge

29. **
Evaluate the incisal edge

30. **
Evaluate the incisal edge

31. **
Evaluate the contact
Evaluate the cervical ridge amount

33. Wheeler's Dental anatomy, physiology, and occlusion". APA (6th ed.) Ash,
M. M. (1993).
Ads AH, El-Zainy MA, , Shenaishen SF, Halawa AM. Fundamentals Of
Tooth Morphology&Physiology. Faculty of Dentistry Ain Shams
University. 2020.