Maxillary second and third molars

Human dentition
Dr. Hazem Al Ajrami
First Year in Dentistry First Semester
Al-Azhar University - Gaza
Lama El Banna

1. 11

2. 2
College of DentistryCollege of Dentistry
Human Dentition Human Dentition
Maxillary Second and Third MolarsMaxillary Second and Third Molars
Dr. Hazem Al AjramiDr. Hazem Al Ajrami

3. 3
Maxillary Second MolarMaxillary Second Molar

4. 4
Universal Numbering System:Universal Numbering System:
2 and 152 and 15
Palmer Notation System:Palmer Notation System:
FDI Numbering System:FDI Numbering System:
17 and 2717 and 27
77andand77

5. 5
Chronology:Chronology:
A.A.First evidence of calcification: First evidence of calcification: 2.52.5 years. years.
B.B.Enamel completed: Enamel completed: 7 7 - - 88 years . years .
C.C.Eruption: Eruption: 12 12 - - 1313years .years .
D.D.Root completed: Root completed: 14 14 - - 1616 years . years .

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Cervico-Cervico-
OcclusalOcclusal
Length Length
ofof
CrownCrown
Length Length
of of
RootRoot
Mesiodistal Mesiodistal
Diameter Diameter
of Crownof Crown
Mesiodistal Mesiodistal
Diameter Diameter
of Crown of Crown
at Cervixat Cervix
Maxillary Maxillary
Second Second
MolarMolar
77
B = 11B = 11
P = 12P = 12
99 77

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Bucco-Bucco-
Palatal Palatal
DiameteDiamete
r of r of
CrownCrown
Bucco-Bucco-
Palatal Palatal
Diameter Diameter
of Crown of Crown
at Cervixat Cervix
Curvature Curvature
of of
Cervical Cervical
Line Line
(Mesial)(Mesial)
Curvature Curvature
of of
Cervical Cervical
Line Line
(Distal)(Distal)
Maxillary Maxillary
Second Second
MolarMolar
1111 1010 11 00

8. 8
This toot supplements the maxillary first molar This toot supplements the maxillary first molar
in function, and it has the same form with in function, and it has the same form with
some variations.some variations.
The proximal contact areas are both in the The proximal contact areas are both in the
same level at the middle third.same level at the middle third.
Absence of the cusp of Carabelli. Absence of the cusp of Carabelli.

9. 9
Buccal AspectBuccal Aspect
The crown is a little shorter cervicoocclusally The crown is a little shorter cervicoocclusally
(by about 0.5 mm.), narrower mesiodistally (by about 0.5 mm.), narrower mesiodistally
(by 1 mm.), but of the same measurement (by 1 mm.), but of the same measurement
buccopalatally.buccopalatally.
The buccal groove is located further distally, The buccal groove is located further distally,
with a resultant larger and longer mesiobuccal with a resultant larger and longer mesiobuccal
cusp, and a shorter and sharper distobuccal cusp, and a shorter and sharper distobuccal
cusp.cusp.

10. 10
MesialDistal

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The occlusal outline on the buccal surface tilted The occlusal outline on the buccal surface tilted
cervically from mesial to distal, this make the cervically from mesial to distal, this make the
buccal surface of the crown appear to be shorter buccal surface of the crown appear to be shorter
on the distal than the mesial. on the distal than the mesial.
The three roots on the maxillary second molar are The three roots on the maxillary second molar are
smaller, less divergent and more parallel in smaller, less divergent and more parallel in
comparison to the first molar.comparison to the first molar.
The palatal root is still the largest and longest The palatal root is still the largest and longest
root, but it is straighter and less curved buccally.root, but it is straighter and less curved buccally.
There is a great chance for the fusion of the two There is a great chance for the fusion of the two
buccal roots or even the fusion of the three roots.buccal roots or even the fusion of the three roots.

12. 12
The buccal roots are about the same length, The buccal roots are about the same length,
they are more nearly parallel and are inclined they are more nearly parallel and are inclined
distally more than those of the maxillary first distally more than those of the maxillary first
molar so that the end of the distobuccal root is molar so that the end of the distobuccal root is
slightly distal to the distal extremity of the slightly distal to the distal extremity of the
crown.crown.
The apex of the mesiobuccal root is on a line The apex of the mesiobuccal root is on a line
with the buccal groove of the crown instead of with the buccal groove of the crown instead of
the tip of the mesiobuccal cusp as found on the the tip of the mesiobuccal cusp as found on the
maxillary first molar.maxillary first molar.

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Palatal AspectPalatal Aspect
The mesiopalatal cusp is smaller and not well The mesiopalatal cusp is smaller and not well
developed as in the maxillary first molar.developed as in the maxillary first molar.
No fifth cusp is present.No fifth cusp is present.
The apex of the palatal root is in line with the The apex of the palatal root is in line with the
distopalatal cusp instead of the palatal groove distopalatal cusp instead of the palatal groove
as was found on the maxillary first molar. as was found on the maxillary first molar.

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Mesial Distal

15. 15
Mesial AspectMesial Aspect
The buccopalatal dimension is about the same The buccopalatal dimension is about the same
as that of the maxillary first molar.as that of the maxillary first molar.
The roots do not spread as far buccopalatally, The roots do not spread as far buccopalatally,
being within the confines of the buccopalatally being within the confines of the buccopalatally
crown outline.crown outline.

16. 16

17. 17
Distal AspectDistal Aspect
Because the distobuccal cusp is smaller than in Because the distobuccal cusp is smaller than in
the maxillary first molar, more of the the maxillary first molar, more of the
mesiobuccal cusp may be seen from this angle.mesiobuccal cusp may be seen from this angle.
The apex of the palatal root is in line with the The apex of the palatal root is in line with the
distopalatal cusp.distopalatal cusp.

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19. 19
Occlusal AspectOcclusal Aspect
The crown is more constricted mesiodistally.The crown is more constricted mesiodistally.
There are two major types of crown form:There are two major types of crown form:
1.1.Rhomboidal typeRhomboidal type resembling the maxillary resembling the maxillary
first molar. It is most frequent and is similar first molar. It is most frequent and is similar
to the first molar except that the rhomboid to the first molar except that the rhomboid
form is more accentuated.form is more accentuated.
2.2.Heart shapedHeart shaped form resembling the maxillary form resembling the maxillary
third molar. The distopalatal cusp being third molar. The distopalatal cusp being
poorly developed of other cusps poorly developed of other cusps
predominate.predominate.

20. 20

21. 21
It is common to find supplemental grooves on It is common to find supplemental grooves on
the occlusal surface of the maxillary second the occlusal surface of the maxillary second
molar which make the surface more wrinkled.molar which make the surface more wrinkled.

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23. 23
Maxillary Third MolarMaxillary Third Molar

24. 24
Universal Numbering System:Universal Numbering System:
1 and 161 and 16
Palmer Notation System:Palmer Notation System:
FDI Numbering System:FDI Numbering System:
18 and 2818 and 28
88andand88

25. 25
Chronology:Chronology:
A.A.First evidence of calcification: First evidence of calcification: 7 7 - - 99 years. years.
B.B.Enamel completed:Enamel completed: 12 12 - - 16 16 years . years .
C.C.Eruption: Eruption: 17 17 - - 2121 years . years .
D.D.Root completed: Root completed: 18 18 - - 2525 years . years .

26. 26
No standard form is observed for this tooth No standard form is observed for this tooth
and thus it is hard to describe a typical and thus it is hard to describe a typical
maxillary third molar.maxillary third molar.
This tooth is the smallest molar from all This tooth is the smallest molar from all
dimensions. The mesial contact area is located dimensions. The mesial contact area is located
in the middle third, while the distal contact is in the middle third, while the distal contact is
absent.absent.
This is the most variable tooth in the upper This is the most variable tooth in the upper
arch. It varies in size, shape, contour and arch. It varies in size, shape, contour and
surface details. The most common crown form surface details. The most common crown form
is the heart-shapedis the heart-shaped which is generally smaller which is generally smaller
and more rounded in all dimensions than the and more rounded in all dimensions than the
second molar.second molar.

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The distopalatal cusp is very small and poorly The distopalatal cusp is very small and poorly
developed or may be absent presenting an developed or may be absent presenting an
occlusal table with three cusps. The groove occlusal table with three cusps. The groove
pattern is variable and may show many pattern is variable and may show many
supplemental grooves.supplemental grooves.
The distopalatal groove is absent.The distopalatal groove is absent.
The root form and number extremely variable, The root form and number extremely variable,
but are smaller in all dimensions.but are smaller in all dimensions.
The most common is the three root type The most common is the three root type
(trifurcated), they are short poorly developed (trifurcated), they are short poorly developed
roots, which are curved distally. However the roots, which are curved distally. However the
roots are sometimes so close together that they roots are sometimes so close together that they
may be completely fused together.may be completely fused together.

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There are two types of occlusal surface There are two types of occlusal surface
outline of the third molar:outline of the third molar:
1.1.The most common occlusal surface outline is The most common occlusal surface outline is
heart shape, where the tooth has 3 cusps heart shape, where the tooth has 3 cusps
(mesiobuccal, distobuccal and mesiopalatal (mesiobuccal, distobuccal and mesiopalatal
cusps).cusps).
2.2.Rhomboidal type with four cusps, the Rhomboidal type with four cusps, the
distopalatal cusp is small and nonfunctioning distopalatal cusp is small and nonfunctioning
cusp. Also the oblique ridge is poorly cusp. Also the oblique ridge is poorly
developed or completely absent.developed or completely absent.

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Buccal AspectBuccal Aspect

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Palatal AspectPalatal Aspect

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Mesial AspectMesial Aspect

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Distal AspectDistal Aspect

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Occlusal AspectOcclusal Aspect

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