permanent first maxillary molars -...
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Permanent first Maxillary Molars
By: Dr. Rana S. AlHamdan
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Main Function of maxiallary & mandibular molars:
Mastication
Rana S. AlHamdan
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They help to maintain:
proper vertical dimension and
the continuity within the dental arch.
Rana S. AlHamdan
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Molars generally have wide occlusal surface
Rana S. AlHamdan
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First molars appears in
the oral cavity at the age
of 6 years old.
Rana S. AlHamdan
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Rana S. AlHamdan
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Mandibular molars precede the maxillary molars
1
2
Rana S. AlHamdan
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So first molar is not a succedaneous tooth
because it has no predecessor
Rana S. AlHamdan
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Maxillary molars are the largest
and strongest tooth, by their
bulk and their anchorage in the
jaw.
Rana S. AlHamdan
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Although crowns on
molars may be
somewhat shorter
than the premolars,
but..their dimensions
are greater in every
respect.Rana S. AlHamdan
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Molars roots are broader at the base and is
trifurcated into three roots (2 buccal and one lingual, Lingual root is the longest )
Rana S. AlHamdan
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2 buccal
Have four cusps
2 lingual Rana S. AlHamdan
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Normal location of the first permanent molar is at the
center of fully developed adult jaw anteroposteriorly…
Rana S. AlHamdan
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This significance position,
first molar is considered
the “cornerstones” of the
dental arch..Rana S. AlHamdan
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The crown is wider B-L than M-D, usually extra dimension B-L is about 1 mm
B
L
MD
Rana S. AlHamdan
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B
L
MD
Has four well-developed cusps (MB, DB, ML, DL)
MBDB
MLDL
Rana S. AlHamdan
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B
L
MD
Has four well-developed cusps (MB, DB, ML, DL)
MBDB
MLDL
The
largest
Rana S. AlHamdan
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B
L
MD
and one supplemental fifth cusp (cusp or tubercle
of Carabelli) lingual to the ML cusp, it can grade
down to series of grooves, depression or pits…
MBDB
MLDL
Rana S. AlHamdan
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three roots are MB and DB and L, gives this tooth maximum anchorage.
MBDB
L
Rana S. AlHamdan
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Lingual root is the longest
root,
it is tapered and smoothly
rounded
L
MBDB
Buccal View
Rana S. AlHamdan
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MB root is not as long, but
broader BL & shaped so that
its resistance to torsion is
greater than that of the
lingual root
L
MBDBMB
L
Mesial ViewBuccal View
Rana S. AlHamdan
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DB root is the smallest, it is
smoothly rounded
L
MBDB
Buccal View
Rana S. AlHamdan
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Buccal Lingual
occlusal
Mesial Distal
Detailed description of Maxillary
1st molar from all the aspects
Rana S. AlHamdan
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Buccal aspect
Rana S. AlHamdan
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Buccal aspect of Max. right first molar.
Distobuccal
rootMesiobuccal
root
Lingual root
Cervical line
Distobuccal
cuspMesolingual
cusp
Mesiobuccal
cusp
Buccal developmental
groove
Root Trunk
(common roots base, between
cervical line & bifurcation)
Rana S. AlHamdan
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The crown is roughly trapezoidal..
Rana S. AlHamdan
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Parts of the 4 cusps can be seen, the MB, DB, ML and DL
Rana S. AlHamdan
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-MB is broader than the DB,
-and the M slope meets its D slope at an obtuse angle..
MBDB
M
slope
D
slope
↑90o
Rana S. AlHamdan
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The mesial slope of the DB cusp meets its distal slope at approximately a
right angle, therefore the DB cusp is sharper than the MB cusp..
Rana S. AlHamdan
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Buccal developmental groove that divides the 2 buccal cusps..
Rana S. AlHamdan
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The buccal groove slants occlusoapically in a line of direction
parallel to the long axis of the DB root..
DB
Rana S. AlHamdan
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Buccal groove becomes more shallow toward its termination,
gradually fading out..
Rana S. AlHamdan
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Lateral to the end of the buccal groove, a developmental dip in the
enamel
Rana S. AlHamdan
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Cervical line not so straight.. This line generally convex and the convexity
toward the roots..
Rana S. AlHamdan
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Mesial outline of the crown follows a nearly straight path, to the contact
area..this crest is approximately 2/3 the distance from cervical line to tip of MB
cusp..
1/3
2/3
1/3
1/3
1/3
Rana S. AlHamdan
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Distal outline of the crown is convex, distal surface is spheroidal.
Crest of curvature on the distal side of the crown is located at a level
approximately half the distance from cervical line to tip of the cusp.
Rana S. AlHamdan
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The distal contact area is in the middle of the middle third.
1/3
1/3
1/3
Rana S. AlHamdan
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Flattened area or a concave area is seen on the distal surface at the cervical
third of the crown
1/3
1/3
1/3
Rana S. AlHamdan
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The three roots may be seen from the buccal aspect
Axes of the roots are inclined distally
Rana S. AlHamdan
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Roots are not straight.
Rana S. AlHamdan
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The point of bifurcation of
the 2 buccal roots is
located around 4 mm
above the cervical line.
Rana S. AlHamdan
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The common root base is called the root trunk..
Rana S. AlHamdan
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Deep developmental groove buccally on the root trunk starts at the bifurcation and progresses downward, becoming shallower until it terminates in a shallow
depression at the cervical line..
Cervical line
Root Trunk
Rana S. AlHamdan
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Lingual root is the longest..
The 2 buccal roots closer in length to each other.
L
Rana S. AlHamdan
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On the average, the roots are about twice as long as the
crown..
≈X 2
Rana S. AlHamdan
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They have large crowns but shorter than the
premolars.
Rana S. AlHamdan
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Lingual Aspect
Rana S. AlHamdan
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Lingual aspect of Max. right first molar..
Mesiobuccal
root
Distobuccal
root
Lingual root
Cervical Line
Fifth cusp
MesioLingual
cusp
DistoLingual
cusp
Lingual developmental
groove
Rana S. AlHamdan
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Smooth curvature of D outline of the crown creates an
arc that is almost a semicircle..
Rana S. AlHamdan
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Shallow depression in the surface extends from the end of
lingual groove to the center of lingual surface of lingual
root at cervical line and then continues in an apical
direction on the lingual root, fading out at the middle 1/3
of the root
Lingual view
Rana S. AlHamdan
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Lingual cusps are the only cusps seen from lingual
aspect
Buccal view Lingual view
Vs.
Rana S. AlHamdan
![Page 53: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/53.jpg)
ML cusp is larger than DL cusp
ML DL
Rana S. AlHamdan
![Page 54: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/54.jpg)
ML cusp width is about 3/5 of M-D crown diameter,
DL cusp width making up the remaining 2/5
ML DL
Mesial side Distal side
Rana S. AlHamdan
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Rana S. AlHamdan
Lingual groove starts approximately at the center of lingual surface
mesiodistally, curves sharply to the distal as it crosses between the
cusps, and continues on to the occlusal surface
![Page 56: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/56.jpg)
MLDL
Fifth cusp appears attached to the ML surface of the ML cusp.
Outlined occlusally by an irregular groove
Rana S. AlHamdan
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Mesiobuccal
root
Distobuccal
root
Lingual root
Cervical Line
Fifth cusp
MesioLingual
cusp
DistoLingual
cusp
Lingual developmental
groove
Cusp ridge of the fifth cusp is approximately 2 mm cervical to the cups
ridge of the ML cusp
2 mm
Rana S. AlHamdan
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All the 3 roots are visible from the lingual aspect.
Lingual root is conical, with bluntly rounded apex
Rana S. AlHamdan
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Lingual Root
Fifth cusp
Mesolingual
cuspMesial
Marginal
Ridge
Mesiobuccal
cusp
Mesial Contact
area
Cervical
Line
Mesiobuccal
Root
Root Trunk
Maxiallry Right First Molar, Mesial Aspect
Rana S. AlHamdan
![Page 60: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/60.jpg)
Increased B-L dimensions can be seen
Rana S. AlHamdan
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Cervical line is irregular, curving occlusally (not more than 1 mm ).
Maximum curvature of the cervical line is above the contact area
1 mm
Rana S. AlHamdan
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Lingual Root
Fifth cusp
Mesolingual
cuspMesial
Marginal
Ridge
Mesiobuccal
cusp
Mesial Contact
area
Cervical
Line
Mesiobuccal
Root
Root Trunk
Mesial contact area approximately at the junction of the middle
and occlusal thirds of crown, Somewhat buccaly rather than in the
center of B-L dimension
![Page 63: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/63.jpg)
Mesial Shallow concavity is usually found above contact
area, this concavity may be continued to the mesial
surface of the root trunk at its cervical 1/3
Cervical 1/3 of the root
Middle 1/3 of the root
Apical 1/3 of the root
Rana S. AlHamdan
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MB root is broad and flattened.
Width of MB root is 2/3 of the crown B-L measurement
at cervical line..
1/3 1/31/3
2/3
B L
Rana S. AlHamdan
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Buccal outline of MB root extends upward
and outward from the crown, with blunt
apex
B L
Rana S. AlHamdan
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Lingual outline of the MB root is relatively
straight from the blunt round apex to the
bifurcation with the lingual root..
B L
Rana S. AlHamdan
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Level of root bifurcation mesially more
closer to cervical line than buccaly
Buccal view Mesial view
Rana S. AlHamdan
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Lingual root is longer than mesial root
but is narrower from mesial aspect.
B L
Rana S. AlHamdan
![Page 69: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/69.jpg)
Lingual root is banana-shaped, extending
lingually
B L
Rana S. AlHamdan
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Distal Aspect
![Page 71: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/71.jpg)
Maxillary Right First Molar, Distal Aspect.
Distobuccal root
Mesiobuccal root
Lingual root
Buccal Developmental
Groove
Distobuccal cusp
Distal Contact Area
DistoLingual cusp
Distal Marginal
Ridge
Cervical Line
Rana S. AlHamdan
![Page 72: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/72.jpg)
There is tendency
of the crown to
taper distally..
Rana S. AlHamdan
![Page 73: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/73.jpg)
That’s why..most of the buccal surface of the
crown may be seen from the distal aspect..
= the B-L measurement of the crown mesially is
greater than the D.
Mesial view Distal view
Vs.
Rana S. AlHamdan
![Page 74: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/74.jpg)
Distal marginal ridge curve sharply in
cervical direction, exposing triangular
ridges on occlusal surface distally.
Rana S. AlHamdan
![Page 75: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/75.jpg)
Cervical line almost straight B-L, occasionlally
it curves apically around 0.5 mm
Rana S. AlHamdan
![Page 76: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/76.jpg)
Occlusal outline is somewhat rhomboidal
Rana S. AlHamdan
![Page 77: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/77.jpg)
Wider mesially than distally &
wider lingually than buccally
M MD D
B B
L L
Rana S. AlHamdan
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ML cusp is the largest MBDL DB fifth cusp.
M MD D
B B
L L
Rana S. AlHamdan
![Page 79: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/79.jpg)
ML cusp is the largest MBDL DB fifth cusp.
M MD D
B B
L L
Rana S. AlHamdan
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ML cusp is the largest MBDL DB fifth cusp.
M MD D
B B
L L
Rana S. AlHamdan
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ML cusp is the largest MBDL DB fifth cusp.
M MD D
B B
L L
Rana S. AlHamdan
![Page 82: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/82.jpg)
ML cusp is the largest MBDL DB fifth cusp.
M MD D
B B
L L
Rana S. AlHamdan
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MD
B
L
Primary cusps 3 :
ML, MB, DB cusps
Secondary cusp:
Tubercule of Carabelli..
“DL common to all max. molars !”
DL cusp becomes progressively smaller
on 2nd and 3rd molars..often
disappearing
ML
MBDB
1 2
3
Rana S. AlHamdan
![Page 84: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/84.jpg)
MD
B
L
Triangular arrangement of cusps is reflected
in the outline of the root trunks of maxillary
molarsRana S. AlHamdan
![Page 85: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/85.jpg)
Oblique ridge is a ridge that crosses the
occlusal surface obliquely
MD
B
L
Oblique ridge reduced in height in the center of occlusal surface, being
at the level of marginal ridge
Rana S. AlHamdan
![Page 86: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/86.jpg)
MD
B
L
Mesial marginal ridge & distal marginal ridge
Rana S. AlHamdan
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MD
B
L
Central fossa : is a concave area bound by the distal slope of the MB cusp, mesial slope of DB cusp, the crest of the oblique
ridge, and the crests of the 2 triangular ridges of the MB and ML cusps..
Central fossa contains developmental and supplemental grooves
Rana S. AlHamdan
![Page 88: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/88.jpg)
MD
B
L
From central pit, buccal developmental groove
radiates buccaly between the buccal cusps.
Rana S. AlHamdan
![Page 89: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/89.jpg)
MD
B
L
Central developmental groove progress and terminates at apex of
the mesial triangular fossa, here it is joined by short
supplemental grooves that radiates into the triangular
fossa..occasionally one or more supplemental groove cross the
mesial marginal ridge of the crown…
Rana S. AlHamdan
![Page 90: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/90.jpg)
MD
B
L
Mesial triangular ridge : it is triangular in shape,
with the base at mesial marginal ridge and its
apex at the point where the supplemental
grooves join the central groove.Rana S. AlHamdan
![Page 91: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/91.jpg)
Transverse groove of the oblique ridge:
groove that cross the oblique ridge transversely joining the central and distal fossae
MD
B
L
Rana S. AlHamdan
![Page 92: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/92.jpg)
Occlusal aspect maxillary right first molar
Mesiobuccal cusp ridge
Central Fossa (shaded area)
Mesial Triangular fossa
Mesial Marginal Ridge
MesioLingual cusp ridge
Oblique ridgeDistoLingual cusp ridge
Distal Fossa
Distal Triangular fossa
Distal Marginal Ridge
Distobuccal cusp ridge
Rana S. AlHamdan
![Page 93: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/93.jpg)
• 2 major fossae :
– Central fossa (roughly triangular
and mesial to the oblique ridge)
– Distal fossa (roughly linear and
distal to the oblique ridge)
• 2 minor fossae:
– Mesial triangular fossa (distal to the
mesial marginal ridge)
– Distal triangular fossa (mesial to
the distal marginal ridge)
Rana S. AlHamdan
![Page 94: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/94.jpg)
• 2 major fossae :
– Central fossa (roughly triangular
and mesial to the oblique ridge)
– Distal fossa (roughly linear and
distal to the oblique ridge)
• 2 minor fossae:
– Mesial triangular fossa (distal to the
mesial marginal ridge)
– Distal triangular fossa (mesial to
the distal marginal ridge)
Rana S. AlHamdan
![Page 95: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/95.jpg)
• 2 major fossae :
– Central fossa (roughly triangular
and mesial to the oblique ridge)
– Distal fossa (roughly linear and
distal to the oblique ridge)
• 2 minor fossae:
– Mesial triangular fossa (distal to the
mesial marginal ridge)
– Distal triangular fossa (mesial to
the distal marginal ridge)
Rana S. AlHamdan
![Page 96: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/96.jpg)
• 2 major fossae :
– Central fossa (roughly triangular
and mesial to the oblique ridge)
– Distal fossa (roughly linear and
distal to the oblique ridge)
• 2 minor fossae:
– Mesial triangular fossa (distal to the
mesial marginal ridge)
– Distal triangular fossa (mesial to
the distal marginal ridge)
Rana S. AlHamdan
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Developmental grooves of Occlusal aspect
of Maxillary right first molar
Buccal Groove
Buccal Groove of Central
Fossa
Central Groove of Central
Fossa
Lingual grooveFifth cusp groove :
Developmental groove that
outlines a fifth cusp
Distal Oblique groove
Transverse groove of
oblique ridge
Central pit
Rana S. AlHamdan
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Extreme Variations !!!
![Page 99: Permanent first Maxillary Molars - KSUfac.ksu.edu.sa/sites/default/files/rds_110_1st_maxillary... · 2015. 11. 27. · MB cusp, mesial slope of DB cusp, the crest of the oblique ridge,](https://reader033.vdocuments.net/reader033/viewer/2022053123/60abee8fc721a92a735206b1/html5/thumbnails/99.jpg)
Abnormal long roots with
extreme curvature
Lingual& DB roots fused
M-D measurment of root trunk smaller
than usual
Fifth cusp with maximum
development
Extreme B-L measurement
v.Long DB cusp, buccal
cusp narrow M-D
Well developed crown while roots poorly
developed
Extreme development of
lingual portion when
compared to buccal
development