This document describes the anatomy and morphology of the maxillary first, second, and third molars. It provides details on the crown and root structures, measurements, developmental chronology, and distinguishing features of each tooth. The maxillary first molar is the largest with 4 well-developed cusps, 3 roots, and variable features like the cusp of Carabelli. The second molar is smaller with a less prominent distolingual cusp. The third molar is the smallest and most variable in shape, often missing.

1. By Dr Ajish M Saji
Deparment of Oral Pathology
Malabar Dental College
Edappal

2. Maxillary first molar
 Largest tooth in the maxillary arch.
 4 well developed cusps and supplemental cusp-cusp of
carabelli/5th cusp.
 3 roots-MB,DB ,lingual root
 Lingual root is the longest root, tapered and smoothly
rounded.
 MB root is not as long as lingual root but is broader
buccolingually so that its resistance to torsion is greater
than lingual root.
 DB root is the smallest and smoothly rounded.

3. Chronology
 First evidence of calcification-at birth
 Enamel completed- 3 -4 yrs
 Eruption- 6yrs
 Root completed- 9-10 yrs

4. Measurement
 Crown length- 7.5mm
 Root length- B -12mm,L-13mm
 MD diameter crown- 10mm
 MD diameter at cervix- 8mm
 BL diameter crown- 11mm
 BL diameter at cervix- 10mm
 Curvature of cervical line(mesial)- 1mm
 Curvature of cervical line(distal)- 0

5. Buccal Aspect
 Crown is roughly trapezoidal.
 Parts of 4 cusps seen.
 MB cusp is broader than DB cusp.
 MB cusp – mesial slope meets its
distal slope at an obtuse angle but for
DB cusp they meet at a right angle. So
DB cusp is sharp.
 Buccal developmental groove divides the
two buccal cusps is equidistant between
MB and DL line angles.

6.  Crown broadest near junction of occlusal &middle
3rd ;narrow near the cervical line
 Mesial outline follows straight path downward &
mesially, curving occlusally as it reaches crest of
curvature, which is at 2/3rd distance from cervical to
MB cusp tip, mesial outline continues downward &
distally becomes congruent with mesial slope of MB
cusp
 Distal outline convex; the distal surface is spheroidal.
The contact area is in middle of the middle third.

7.  All three roots can be
seen.
 MB root curves distally
starting at the middle
third.
 Point of bifurcation 4mm
above cervical line.
 Developmental groove
starts at bifurcation and
progresses downward and
terminates in shallow
depression at cervical line.

8. Lingual aspect
 ML cusp is much larger
and longest.
 MD width is about 3/5th of
the MD crown diameter,
with the DL cusp making
up the remaining 2/5th.
 Angle formed by mesial
outline & mesial slope of
ML cusp is 90º. Mesial &
distal slope of ML cusp
forms an obtuse angle.

9.  DL cusp is spheroidal and smooth.
 Lingual developmental groove starts in the
centre of the lingual surface MD, curves
sharply to the distal as it crosses between the
cusps, continues to the occlusal surface.
 5th cusp on ML surface of MLcusp outlined by
irregular developmental groove starting in
depression of ML line angle extending occlusaly
toward point of ML cusp making obtuse angle
turn toward terminus of lingual groove & fading
out near lingual groove terminus .
 Cusp ridge of 5th cusp is 2mm cervical to cusp
ridge of ML cusp.
 All roots are visible-lingual root is conical ,
terminating in a bluntly rounded apex. Apex of
lingual root in line with lingual groove.

10. Mesial aspect
 Crown outline is
trapezoidal.
 Starting at the cervical line
buccally, outline makes arc
to crest of curvature with
in cervical 3rd (0.5mm).
Outline describes shallow
concavity occlusal to crest
of curvature, then becomes
slightly convex as it
progresses downward and
inward to MB tip

11.  Lingual outline curves
outward & lingually,
Crest of curvature near
middle third of the
crown.
 MMR confluent with
MB and ML cusp ridges,
irregular, curving
cervically 1/5 crown
length and centering its
curvature below center
of crown BL.

12.  Cervical line curve
oclusally not more than
1mm.
 Contact area is apical to
marginal ridge closer to it
than cervical line, junction
of the middle and occlusal
thirds, buccal to center.
Shallow concavity above
CA and this continued to
mesial surface of root
trunk.
 Roots-MB broad &
flattened
 Lingual root longer,
narrower at middle and
apical 3rd outside confines
of crown projection.

13. Distal aspect
 Taper distally on the
buccal surface, most of
buccal surface seen.
 DMR dips cervically
exposing triangular ridges
on distal portion of
occlusal surface.
 Cervical line is straight.

14.  Distal surface convex
expect for small area
near DB root at cervical
3rd this extends on distal
surface of root to
bifurcation.
 DB root narrower and
more pointed than MB-
buccal outline within
confines of MB root,
lingual outline slightly
concave.

15. Occlusal aspect
 Outline rhomboidal-with 2 acute
and 2 obtuse angles.
 Wider mesially than distally.
 Wider lingually than bucally.
 4 major cusps & one small minor.
 ML largest followed in
descending border MB,DL,DB,5th
cusp

16.  Developmentally only 3 major cusps
considered as primary-ML & 2 buccal
cusps.
 Cusp of carabelli regarded as secondary.
 Triangular arrangement of cusp is
reflected in outline of root trunk of
maxillary molars when tooth sectioned
in those areas.
 DL cusp become progressively smaller
on 2nd &3rd molars disappearing as
major cusp.
 Thus triangular arrangement of 3 molar
cusps is called maxillary molar
primary cusp triangle.
Cusps

17.  Ridges are oblique ridge and
marginal ridges.
 Oblique ridge crosses occlusal
surface obliquely & is union of
triangular ridge of DB cusp & distal
ridge of ML cusp.
 OR reduced in height in center of
occlusal surface being on level with
the marginal ridges sometimes
crossed by transverse groove of OR.
 MMR and DMR are irregular ridges
confluent with mesial and distal
cusp ridges of mesial and distal
major cusps.
Ridges

18.  Major fossa-Central fossa, Distal
fossa.
 Minor fossa-Mesial triangular
fossa, Distal triangular fossa.
 Central fossa-roughly triangular
mesial to OR. Concave area
bounded by distal slope of MB
cusp, mesial slope of DB cusp,
crest of oblique ridge and crest
of 2 triangular ridges of MB &
ML cusps.
Fossa

19.  CF has central developmental
groove and supplemental
groove.
 Center of CF is central pit.
 From pit central developmental
groove radiate bucally onto buccal
surface.
 Starting at central pit CDG
progress in mesial direction at
obtuse angle to buccal groove and
terminate at apex of mesial
triangular fossa, here joined by
short supplemental groove,
occasionally one or more
supplemental groove cross MMR.

20.  Mesial triangular fossa-triangular
shape base at MR & apex at point
where supplemental grooves join
central groove.
 Additional short developmental
groove radiate from central pit at
obtuse angle to buccal & central
grooves which fades before
reaching crest of OR, when
crosses OR it join CF and DF with
shallow groove called transverse
groove of OR.
 Distal fossa-linear form, distal to
OR, irregular developmental
groove transverses it-distal
oblique groove.

21.  Distal oblique groove connects
with lingual developmental groove
at junction of cusp ridges of ML
and DL cusps.
 5th cusp groove.
 Distal oblique groove show several
supplemental grooves-two
terminal branches form 2 sides of
triangular depression mesial to
DMR.
 Contact area-mesial and distal
contact area near center of BL
side, MCA more buccal.
 Lingual outline of DL cusp in line
with lingual outline of 5th cusp,
cusp ridge of DL extends lingually
farther than cusp ridge of ML
cusp.

22. Maxillary second molar
 Supplements 1st molar in function.
 Shorter in all dimensions-crown 0.5mm shorter, roots 1mm
shorter, MD crown width at contact area less by 1mm.
 Distobuccal cusp not as large or well developed.
 Distolingual cusp smaller.
 No 5th cusp.
 2 types-1)resembles 1st molar-rhomboidal outline.
 2)resembles 3rd molar-heart shaped form, DL cusp poorly
developed.

23. Chronology
 First evidence of calcification- 2 ½ yrs
 Enamel completed 7 - 8yrs
 Eruption 12 – 13yrs
 Root completed 14 – 16 yrs

24. Measurement table
 Crown length -7mm
 Root length -B 11mm,L 12mm
 MD diameter crown -9mm
 MD diameter at cervix -7mm
 BL diameter crown -11mm
 BL diameter at cervix -10mm
 Curvature of cervical line(mesial) -1mm
 Curvature of cervical line(distal) -0

25. Buccal aspect
 Crown outline -trapezoidal
 Crown is broadest at junction of occlusal &
middle 3rd and narrowest near cervical line.
 2 cusps-MB & DB cusp,DB cusp smaller.
 Buccal developmental groove shorter.
 Buccal pit less often present, when present
shallower than on 1st molar.
 Crown is tilted very slightly distally-occlusal
surface slants cervically from mesial to distal.
Crown height shorter on distal than on mesial
side.

26.  Buccal roots are of about
same length, nearly
parallel & inclined
distally more than I
molar, so end of DB root
is slightly distal to distal
extremity of crown.
 Apex of MB root is on a
line with buccal groove.

27. Lingual aspect
 Crown outline- trapezoidal
 Lingual surface narrower in cervical
3rd than in middle third.
 Width less than 1st molar.
 DL cusp smaller than ML cusp.
 5th cusp absent.
 Apex of lingual root is in line with
DL cusp.

28. Mesial aspect
 Crown similar to 1st molar
except 5th cusp absent.
 Outline form-trapezoidal.
 BL dimension is same as
that of I molar but crown
height is less.
 Roots do not spread as far
buccolingually as I molar,
but are within confines of
BL crown outline.

29. Distal aspect
 DB cusp smaller so more of MB
cusp seen.
 Crown length less.
 Apex of lingual root in line with DL
cusp
 DB root more pointed than MB
root.
 Distal surface of DB root is slightly
convex without longitudinal
depression.

30. Occlusal surface
 Outline rhomboidal. In comparison with I
molar, the acute angles are less and obtuse
angles greater.
 Slightly wider buccolingually than
mesiodistally.
 Tapers from buccal to lingual.
 Oblique ridge less prominent, extends from
ML to DB cusp
 4 cusps-ML,MB,DL,DB
 Narrower on lingual & distal sides
 Not uncommon to find more supplemental
grooves, accidental grooves, and pits than on
1st molars.

31. Differences of II from I molar
 Smaller dimension than I molar.
 Roots flare less, bend more to distal.
 Crown taper lingually and distally.
 Both distal cusps are smaller.
 Buccal groove shorter & mostly without pit.
 MB root is in line with buccal groove.
 Lingual root is in line with DL cusp.
 Less prominent oblique ridge.
 Occlusal parallelogram more twisted(1st molar
squarish)

32. Differences between primary and
permanent maxillary molars
 Primary molar crowns are wider MD.
 Primary I molar is smaller than primary II molar.
 Primary molar crowns have a narrow occlusal table.
 Buccal cusps are not sharpe, cusp slopes meet at an
obtuse angle.
 Root furcations are nearer to the crown with little or
no root trunk.
 Roots are thin, slender and widely spread.

33. Maxillary third molar
 Smallest of all three.
 Much variable size and shape, missing tooth.
 Shortest in length of all permanent teeth.
 Last tooth hence distal surface not in contact with any
tooth, occludes only with mandibular 3rd molar (only
one antagonist).
 Overall root length shorter by 2mm. Root trunk longer
than 1st &2nd molar.

34. Chronology
 1st evidence of calcification 7 - 9yrs
 Crown completed 12 – 16yrs
 Eruption 17 – 21yrs
 Root completed 18 – 25 yrs

35. Measurement
 Crown length - 6.5mm
 Root length - 11mm
 MD diameter crown - 8.5mm
 MD diameter at cervix - 6.5mm
 BL diameter crown - 10mm
 BL at cervix - 9.5mm
 Curvature of cervical line(mesial) - 1mm
 Curvature of cervical line(distal) - 0

36. Buccal aspect
 Crown length shorter
cervico-occlusally,
narrower mesiodistally
than 2nd molar.
 Roots are fused, shorter
and have a distinct slant
to the distal giving apices
more distal relation to
center of crown.
 MB cusp slightly longer
and wider than DB cusp.

37. Lingual aspect
 Crown taper from buccal
to lingual.
 One large lingual cusp so
no lingual groove
evident.
 In many cases, poorly
developed DL cusp with
developmental groove
lingually.

38. Mesial aspect
 Fused roots bifurcation
in apical 3rd .
 Root portion is
considerably shorter in
relation to crown length.
 Both the crown and root
portions tend to be
poorly developed, with
irregular outlines.

39. Distal aspect
 Most of buccal surface
can be seen.
 More of occlusal surface
seen than on 2nd molar
because of more acute
angulation of occlusal
surface in relation to
long axis of root.
 Crown height is short.

40. Occlusal aspect
 Heart-shaped outline.
 Lingual cusp is large & well
developed
 Little or no DL cusp
evident which gives a
semicircular outline to
tooth from one contact
area to other
 Three functioning cusp-2
buccal and 1 lingual.
 Presents many
supplemental and
accidental grooves.