1. Molars
Rowida Abdalla,DDS

2. Maxillary molars

3. General features Non succedaneous teeth Largest maxillary teeth
They have the largest occlusal surfaces of any of the teeth
Crowns are broader buccolingually than mesiodistally
3 roots 2 buccal and one palatal
They decrease in size as they go posteriorly therefore first molar is the largest and third molar is the smallest.

4. Functions
1-Grinding of food
2-provide vertical facial support

5. 3- 1st molars relation is one of the keys to normal occlusion

6. Eruption Times 1st molar erupts around 6-7 yrs ( 6 yr molar)
2nd molar erupts around 12 yrs
( 12 yr molar)
3rd molar erupts from 17-21
but shows sigfnificant variation
May be congenitally missing !

7. Permenant Maxillary First Molars

8. Permenant maxillary first Molar
General features
Development
Average measurments
Crown
Occlusal
Buccal
Lingual
Mesial
Distal
Root

9. The permenant Maxillary 1st molar General featurs
Largest maxillary tooth
Least morphological variation , most are very similar

10. Average measurments

12. The crown has 5 aspects 1- Occlusal 2- Buccal 3- Lingual 4- Mesial
5- Distal

13. Occlusal Aspect Geometric shape: varies from square to rhomboidal
Mesiobuccal and distolingual line angles
are acute
Average Dimensios
The buccolingual > Mesiodistal dimension
The buccolingual measurement of the
crown mesially is greater than distally
Boundaries of the Occlusal Surface :
• Mesial and distal cusp ridges of four major
cusps
• Mesial and distal marginal ridges.

14. Occlusal Aspect Occlusal Surface within Boundaries:
The occlusal surface exhibits:
ELEVATIONS :-
• Cusps and Ridges
DEPRESSIONS:
• Grooves and pits
• Fossae

15. Mesiolingual CUSPS Mesiobuccal Distobuccal Distolingual
Cusp of Carabelli
Carabellis trait. The fifth cusp may be well developed into a large cusp or may show traces of its development in the form of
grooves, depressions or pits. When well developed, the fifth cusp ridge is cervically
placed than the cusp ridge of mesiolingual cusp. It is usually separated by the mesiolingual cusp by a groove.

16. Each cusp has Mesial and Distal cusp ridges and a triangular ridge of its own slopping towards the center of the occlusal surface
oblique ridge: formed by the union of the triangular ridge of the distobuccal cusp and the distal ridge of the mesiolingual cusp. It is at the same level as the marginal ridges and is sometimes crossed by a developmental groove
Marginal Ridges :The mesial and distal marginal ridges are well developed. The distal marginal ridge is shorter and is at a lower level than the mesial marginal ridge
RIDGES
There are inclined planes on either side of each triangular ridge

18. Foassae Major Fossae Minor Fossae
There are two major and two minor fossae.
Major Fossae
• The central fossa is a large triangular depression
in the center of the occlusal surface mesial to the oblique
ridge.
The distal fossa is small linear developmental depression
distal to the oblique ridge.
Minor Fossae
Mesial triangular fossa is a triangular depression distal to mesial marginal and mesial pit for its apex.
The distal triangular fossa: mesial to distal marginal ridge and distal pit at its apex. Supplemental grooves radiate from the distal pit forming the sides of triangle

19. 6 Main Grooves
1-Central developmental groove 2-Buccal developmental groove: It runs buccally from the Central pit to the buccal surface of the crown separating the two buccal cusps.
Central developmental groove: It runs in a
mesial direction and ends at the apex of mesial triangular fossa where it is joined by supplemental grooves. This groove separates the triangular ridges
of mesiobuccal and mesiolingual cusps.
Grooves The maxillary 1st molar exhibits several developmental and supplemental grooves on its occlusal surface. The developmental grooves are situated at the bottom of deep long sulci traversing across the occlusal surface in different directions.
There are several supplementary grooves especially at the apices of mesial and distal triangular fossae. Some of these supplemental grooves may cross the marginal ridges

20. 6-Fifth cusp groove: It separates the fifth cusp from
3- lingual developmental groove which runs the lingual surface separating the two lingual cusps.
4-Transverse groove of oblique ridge: It runs in a distolingual direction from the central pit and crosses the oblique ridge to reach the distal fossa.
5-Distal oblique groove It is irregular and runs in an oblique direction; parallel to the oblique ridge.
This groove separates the distolingual cusp from therest of the occlusal surface
6-Fifth cusp groove: It separates the fifth cusp from
the mesiolingual cusp
Multiple supplemental grooves
which forms the primary triangle of maxillary molars • The distal oblique groove joins the

21. pits Central Pit It is a pin point depression in the
central fossa at the junction of the Central
And buccal Dev.Grooves
Mesial Pit It is at the apex of mesial triangular
fossa developmental groove terminates at this pit.
Distal Pit It is at the apex of the distal triangular fossa and the distal oblique grooves ends at this pit.
Pits Three pits can be noted on the occlusal surface of maxillary 1st molar.
Central Pit • It is a pin point depression in the central fossa. Three major developmental grooves originate from the central pit and run in three different directions. The three grooves are at obtuse angles to each other. They are: – The buccal developmental groove radiating in a buccal direction. – The central developmental groove running mesially – Transverse groove of oblique ridge running distally.
The central fossa is bounded by the distal slope of the mesiobuccal cusp, mesial slope of the distobuccal cusp, the crests of the oblique ridge and the crests of triangular ridge of mesiobuccal and mesiolingual cusps. –

22. Maxillary molar primary cusp triangle
• A triangular outline can be visualized by tracking the cusp ridges of three
primary cusps, the mesial marginal ridge and oblique ridge
• The distolingual cusp becomes progressively smaller on 2nd and 3rd maxillary molars
The cusp of Carabelli present only in the 1st molar is considered as a secondary cusp
• This triangular arrangement of the three primary cusps is characteristic of all maxillary molars and is called as the maxillary molar primary cusp triangle.
• These three primary cusps can be seated on the root trunk divided into three roots
From the developmental point of view, the maxillary molars have only three
primary cusps namely, the mesiobuccal, the distobuccal and the mesiolingual

23. Buccal Aspect Geometric shape:. Trapezoidal Cusps:
All the cusps are visible
-The MB cusp is widest but the DB cusp is more pointed.
-Both cusps are nearly of same length
-The buccal developmental groove runs for half the length
of buccal surface and ends in the buccal pit.
Mesial Outline :The maximum convexity is at the occlusal third of the crown.
Distal Outline The distal outline is a more convex arc. Its maximum convexity is at the middle third of the crown.
Cervical Outline irregular and curves slightly in an apical direction.
The buccal aspect has a trapezoidal shape with the shorter uneven side towards the cervical portion
The buccal surface is more convex in the cervical third, slightly concave/flattened in the middle third and is convex again in the occlusal third of the crown.
Mesial Outline :The maximum convexity of mesial outline is at the occlusal third of the crown.
Distal Outline The distal outline is a more convex arc. Its maximum convexity is at the middle third of the crown.
Cervical Outline The cervical line on buccal surface of the crown is irregular and curves slightly in an apical direction.

24. Lingual Aspect Geometric shape: Trapezoidal. Cusps:
-Only lingual cusps can be seen
-ML cusp larger than DL
-DL is smooth and spheroidal
-separated by lingual dev.Groove
-Carabelli’s trait can be seen
Mesial Outline: Straight
Distal Outline: More convex
Only lingual cusps can be seen from the lingual aspect as
the shorter buccal cusps are obscured.
•• The mesiolingual cusp is much larger than the distolingual
cusp which is smooth and spheroidal.
•• The lingual development groove separating the two
lingual cusps is confluent with the distolingual cusp, and
extends mesiocervically to end at the center of lingual
surface.
•• The characteristic feature of lingual surface of maxillary
1st molar is the presence of some expression of Carabelli’s
trait. The fifth cusp may be well developed into a large

25. Mesial Aspect Buccal outline: Height of contour in cervical third
Geometric shape : trapezoidal
Buccal outline: Height of contour in cervical third
Lingual outline : convex arc , Height of contour in middle third
Cervical outline curves occlusally
Mesial Contact area : Junction of occlusal and middle thirds
Mesial Aspect
Crown Outlines
Buccal Outline
•• The buccal outline is convex in cervical third and flattens
out as it runs occlusally
•• Height of contour of the buccal outline is within the
cervical third.
Lingual Outline
•• The lingual outline is a more convex arc from cervical line
to the tip of mesiolingual cusp
•• Height of lingual contour is at the middle third of the
crown
•• The lingual outline curves inwards when a well developed
fifth cusp is present.
Occlusal Outline
It is formed by the mesial marginal ridge along with the
triangular ridges of mesiobuccal and mesiolingual cusps
towards the center of the occlusal surface.
Cervical Outline
Cervical outline on mesial surface curves occlusally up to
1 mm.
Mesial Surface within the Outlines
•• The mesiobuccal, mesiolingual and fifth cusps are seen
from mesial aspect.
•• The cusp tips of mesiolingual and mesiobuccal cusp are
within the confines of the root trunk.
•• The mesiolingual cusp tip is on line with the long axis of
the lingual root. The mesiobuccal cusp tip is on line with
the buccal outline of the mesiobuccal root.
•• There is a concavity cervical to the contact area which
may extend onto the cervical portion of root trunk.
•• The mesial contact area is at the junction of occlusal and
middle third of the crown and is more buccally placed
buccolingually.

26. Distal Aspect Geometric Shape: Trapezoidal
Same As mesial aspect but BL measurment is less
Cusps: DB and DL cusps
The distal contact area is at the center of the crown both
cervico-occlusally and buccolingually.
Geometric shape: It is trapezoidal similar to mesial aspect.
The distal aspect has four outlines as mesial aspect.
Crown Outlines
Buccal Outline
The buccal outline is similar to that of the mesial aspect,
except that some portion of buccal surface can also be seen as
the buccal surface of the crown slants distally.
Lingual Outline
The lingual outline is smoothly convex from cervix to the
distolingual cusp tip.
Occlusal Outline
The distal marginal ridge is shorter and at a lower level than
the mesial marginal ridge. Thus, some part of occlusal surface
with triangular ridges of distal cusps may be seen.
Cervical Outline
The cervical line on distal surface is nearly a straight line
without much curvature.
Distal Surface within the Outlines
•• Only distobuccal and distolingual cusps are seen from
distal aspect
•• The distal surface is narrower than the mesial surface as
the crown tapers towards distal aspect
•• The distal surface is smoothly convex except for a concave
area near the cervical line
•• The distal contact area is at the center of

27. Roots
Root trunk is about 1/3 the root length is well within the confines of the crown
The palatal root is wider mesiodistally but narrower buccolingually. It extends lingually and stretches out of the confines of the crown before bending back in a buccal direction at its apical third
The mesiobuccal root is broader buccolingually than mesiodistally.
The distobuccal root is the smallest root and tilts distally
The roots are strongly developed and designed to
withstand the occlusal forces. The

28. MB of mandibular Second molar

29. Maxillary 2nd molar

30. Maxillary 2nd molar General features Development Average measurments
Crown
Occlusal
Buccal
Lingual
Mesial
Distal
Root

31. General Features
The permanent maxillary 2nd molar resembles the permanent
maxillary 1st molar closely and supplements it in function
No 5th cusp
Crown slightly shorter than maxillary permanent 1st molar
roots are as long as the roots of maxillary permanent 1st molar.
But not as divergent
The distobuccal cusp
is somewhat less well developed than that in maxillary 1st
molar. The distolingual cusp is smaller leaving the maxillary
molar primary cusp triangle more prominent

32. Two forms:
Four cusp type with rhomboidal occlusal design. This type is more common and resembles maxillary 1st molar in occlusal form.
.Three cusp type with heart-shaped occlusal aspect resembling maxillary 3rd molar.

34. Occlusal Aspect In the four-cusp type: rhomboidal.
the mesiobuccal and distolingual line
angle are more acute
-The distobuccal and mesiolingual line angles are more obtuse.
In the three-cusp type: heart shaped, highlighting the primary cusp triangle of the maxillary molars - The distolingual cusp is very small.

35. Occlusal Aspect (compared to 1st M)
Smaller than 1st molar
Less developed Oblique Ridge
More supplementary grooves
ML cusp smaller
No cusp of carabelli M2 M1

37. M2 M1

38. Distal View
•Shorter distal cusps
•A greater portion of the occlusal surface is seen

39. Maxillary 2nd molar

40. Roots Roots are closer together MB and DB are nearly parallel
Palatal root is more distal
1st Molar
2nd Molar

41. Maxillary 3rd molars

43. General featurs of 3rd molars
Highly variable in their size and form than any other teeth
May be congenitally missing or impacted
Crown is smaller than second maxillary permanent molar
The tooth assists the 2nd molar in function.
The permanent maxillary 3rd molars, in both the dental arches
are highly variable in their size and form than any other teeth.
They are the most common teeth to be congenitally missing. In
maxillary 3rd molar crown is smaller and shows resemblance
to heart shaped type of second maxillary permanent molar
when viewed occlusally (Fig ). The distolingual cusp is
very small and poorly developed, or may even be completely
absent. The tooth assists the 2nd molar in function. The roots
are shorter and have a strong tendency to fuse. Sometimes,
the maxillary 3rd molars appear as developmental anomalies
with little or no resemblance to adjacent teeth. The maxillary
3rd molar is directly compared with the maxillary 2nd molar
in its description

44. Buccal cusps

45. •DB cusp is of minimal size •Occlusal surface is small
•Oblique ridge, if present is barely visible
Oblique
•Many supplemental grooves ridge
•Predominate crown shape is heart shaped
•DL cusp poorly developed, often absent
DL cusp

46. Roots
•Much shorter cervicoapically
•Commonly fused, functioning as 1 large root
•Distinct slant to the distal

48. Distal View Most of the buccal surface is visible DL cusp absent
DB cusp reduced in size

49. Clinical Considerations
3rd molars are the most common teeth to be congenitally
Missing.
What is the 2nd most common tooth to be cogenitally missing ?
3rd molars are the most common teeth to be impacted
What is the 2nd most common tooth ?
They often erupt buccally rather than in line
with the dental arch due to shorter space.