5. .First permanent molar to calcify and erupt
.It is known as six years molar tooth
?WHY
.Its number in the lower arch is # 6
&
.Its eruption date is six years
Functionally, it is considered as the key of
.occlusion

6. :No. of surfaces
It has five surfaces
BUCCAL
LINGUAL
:No. of roots
It has 2 roots one mesial
.& one distal
MESIAL
OCCLUSAL
DISTAL

7. BUCCAL SURFACE
The geometric outline: Trapezoidal
with the small uneven side present
cervically.
D
Mesial outline: concave till the contact
area at the junction of the occlusal and
middle 1/3.
Distal outline: convex till the contact area
beneath the distal cusp ridge.
M

8. Occlusal outline: formed by 3 cusps,
MB, DB, D
D
Cervical outline: straight with dipping
into the root bifurcation
M

9. Surface anatomy:the buccal surface is
convex with the maximum convexity at
the cervical 1/3 representing the cervical
.ridge
Developmental grooves MB &DB
. separating the three buccal cusps
•
2D
Developmental depression run M-D in*
.the middle 1/3
M

10. The Roots:
The Roots:
*The roots are twice the length of the crown.
The mesial root is directed mesially till the middle 1/3
then it curves distally.
The distal root is straight and directed distally .
M
D
* Root trunk: 3 mm.
•The axis of the roots are inclined
• distally
* Deep developmental groove
extend on the root trunk.

11. LINGUAL SURFACE
* Lingual convergence
Mesial outline: Straight till the contact
area at the junction of the occlusal and
middle 1/3
Distal outline: Convex till the contact
area beneath the distal cusp ridge
M
D

12. Occlusal outline: formed by 2 lingual M
cusps, ML, DL of nearly equal width
Cervical outline: Irregular with dipping
into the root bifurcation
:Surface anatomy
Lingual developmental groove separating
the two lingual cusps.
D

13. BUCCAL
LINGUAL
:The root trunk appears longer on the ling. surface due to
the occlusal position of cervical line*
Lingual conversion *

14. MESIAL SURFACE
The geometric outline: Rhomboid and
inclined lingually.
:Notes
B
ML cusp is more pointed than MB cusp -1
(( because it is out of occlusion
The cervical line slants occlusally from the- 2
.buccal to the lingual side
L

15. MESIAL SURFACE
:Surface anatomy
The surface is concave cervical to*
the contact area which is centered
B-L below the crest of marginal
ridge
Deep developmental depression on the*
.mesial surface of the root
B
L

16. DISTAL SURFACE
L
MESIAL SURFACE
B
L
The crown is shorter distally*
*There is a distal convergence
*DMR is U- shape, shorter and more cervically than MMR
*Distal contact area is located below the distal cusp more
to the buccal .Distal DG is the extension of the CDG on the
distal surface.The M root is broader than the D root.

17. OCCLUSAL SURFACE
B
The geometric outline: Hexagonal with
3 buccal sides , one lingual ,one mesial
and one distal .
M
* The crown measurements
is larger MD than BL .
* The crown converge lingually
and distally
D
L

18. Anatomical landmarks:
B
Elevations:
*5 cusps with 5 triangular ridges
M
D
MMR and DMR*
L

19. Anatomical landmarks:
B
Depressions:
major central fossae + pit 1*
Minor fossae ( mesial and distal 2*
(triangular fossae
M
:Developmental grooves*
.Central groove is zigzag in its MD coarse
MB groove , DB and L groove separating
.the five cusps
D
L

20. Pulp cavity☻
Buccal view
►Pulp Chamber:
. The pulp chamber is broad MD.It is almost rectangular in shapeThere is a pulp horn beneath eachcusp
Mesial view
:Root Canals►
-3 main root canals.
-M root has 2 root canals while D root has 1
root canal.

21. Note:
The two mesial root canals appear in x – ray
overlapping each other.

22. :Abnormalities you may find
.Three or four roots- 1
.Four root canals- 2

24. Enumerate the names of the following
?elevations and depression
Central groove-1
MMR-2
Central fossa-3
Distal triangular fossa-4
Mesio-buccal groove-5

25. :Label the different surfaces
Buccal surface
Lingual surface
Mesial surface
Distal surface

26. ?What is this

27. ?What is this

28. ?What is this

29. ?What is this

31. :No. of surfaces
It has five surfaces
BUCCAL
:No. of roots
It has 2 roots
LINGUAL
MESIAL
OCCLUSAL
DISTAL

32. BUCCAL SURFACES
Geometric outline: Trapezoid
with small uneven side located
cervically
M
: Anatomical Landmark
.Buccal developmental groove may end in a buccal pit
.MB cusp is longer than the DB cusp
The roots are closer and nearly
parallel with more pointed apex
.than 6 ,the are directed distally
D

33. LINGUAL SURFACE
D
The Crown
The lingual cusps are more pointed
than buccal cusps.
Anatomical Landmark: Lingual
developmental groove never pitted.
The Roots
Short root trunk with a developmental
depression.
M

34. MESIAL SURFACE
The geometric outline:
Rhomboidal with lingual
inclination
*MMR is concave
The mesial root is only*
visible
Longitudinal depression on the*
mesial surface of mesial root
L
B

35. DISTAL ASPECT
B
DMR is concave but less*
angular than MMR
Distal root is narrower than mesial*
root, so both roots are seen
L

36. B
OCCLUSAL SURFACE
The geometric outline:
M
Rectangular. D
Note:
* Disto-Lingual convergence.
* Mesio-Distally is larger than bucco
-lingually.
L

37. B
OCCLUSAL SURFACE
The geometric outline is rectangular
Anatomical landmarks:
Elevations:
*4 cusps with 4 triangular ridges ( mesial
cusps are larger than distal cusps).
.Mesial and distal marginal ridge *
M
D
L

38. B
:Depression
major central fossa with central pit 1*
Minor fossae ( mesial and distal 2*
)triangular fossae
D
Developmental grooves: form a typical*
Cross pattern
Supplemental grooves radiate from the *
developmental grooves
Note : All grooves provide important escape
ways for food during mastication
M
L

39. Pulp cavity☻
Pulp Chamber:
M
DB
Bucco-Lingually, the pulp ► chamber is square
Mesio-Distally, the pulp►
chamber is rectangular
There is pulp horn beneath eachcusp
:Root Canals
-3 main root canals.
-M root usually has 2 root canals while D root
has 1 root canal
L

40. Pulp cavity☻
M
Note:
Cervical cross section:
Triangular due to small dimension
distally
Mid root section:
*M root is kidney shape with 2 small
canals
*D root is oval with 1 large rounded
canal
D B
L

42. :No. of surfaces
It has five surfaces
BUCCAL
MESIAL
LINGUAL
OCCLUSAL
DISTAL

43. BUCCAL SURFACE
The 3rd molar is either 4 or 5 cusp*
type .Type 1&Type II
D
The buccal surface is convex*
Short roots (M and D) may be 2 *
fused in all or part of their length
The roots are more inclined distally*
than 1st and 2nd molars
M

44. MESIAL SURFACE
B
L
The buccal cusp tips are closer to the
lingual cusp tips giving a small
occlusal table
DISTAL SURFACE
There is a distal convergence
Distal root is narrower than mesial
root, so both roots are seen
L
B

45. OCCLUSAL SURFACE
The geometric outline:
Rectangular or oval
B
M
D
There are numerous supplemental
grooves and pits give a wrinkled
appearance
L

46. ☻ Note:
1-The 3rd molar may show multiple
variations in the size and shape.
The pulp cavity may also show great- 2
variations in the size and shape
The pulp chamber of 8 is larger than other- 3
molars because it is younger than other
molars by 9-11 years

47. ?What is this
L. surface 7

48. ?What is this
D. Surf. 7

49. Occ. Surf. 7

50. MMR 7

51. DL cusp 7

52. CDG 7

53. BDG 7

54. M F7