Prof. Rooban Thavarajah's Lecture Series - Morphology of Human Deciduous Maxillary Molar Tooth for first BDS students

1. Prof. Rooban Thavarajah
Tooth Morphology
Lecture Series
Dr. Rooban Thavarajah

2. Dr. Rooban Thavarajah
Deciduous Dentition
Maxillary Molars

3. BACK GROUND
 Does not resemble any other CROWN -
nearest similarities to premolars
 Root form is typical of maxillary molars.
 Crown - greatest dimension BP
 Two prominent cusps - MB & ML cusps.
two distal cusps esp. DL are diminished.
Dr. Rooban Thavarajah

4. Dr. Rooban Thavarajah
BUCCAL ASPECT
 Does not resemble any other teeth
 Buccal
 Greatest width MD @ contact areas
 Converges towards cervix
 Narrower look @ cervix
 Smaller than 2nd
molar
 3 roots- Palatal big, mesial, short distal
 Bifurcation of buccal roots @ CEJ

5. BUCCAL ASPECT
 MD diameter is much greater than crown
height.
 Proximal outlines are convex, and constrict
greatly toward cervix
 Heights of contour – contact areas - near
junction of occlusal and middle thirds.
Dr. Rooban Thavarajah

6. BUCCAL ASPECT
 Occlusal outline – straight - contour of cervical line -
depth of curvature - much greater toward mesial than
distal - crown - being offset toward mesial.
 Occlusally, buccal surface is mostly flat, but in gingival
third cervical ridge is prominent, especially mesial
portion.
 Surface has crest of curvature in cervical third.
 Smooth surface
Dr. Rooban Thavarajah

7. PALATAL ASPECT
Dr. Rooban Thavarajah

8. PALATAL ASPECT
 ML cusp is short, bulky and prominent in
occlusal outline.
 DP cusp is small DB cusp is also visible
 Cervical line is evenly, slightly, curved toward
apex.
 Palatal surface is convex and smooth without
grooves or depressions.
 Height of contour - more cervically located, at
about middle & cervical third junction
Dr. Rooban Thavarajah

9. MESIAL ASPECT
 Disparity between BP widths @ its cervical
and occlusal margins is much more
 Cervically, dimension is considerably wider,
due to prominent cervical ridge on buccal, as
well as greater taper of buccal and lingual
outlines toward occlusal.
Dr. Rooban Thavarajah

10. MESIAL ASPECT
 Buccal outline is dominated by cervical ridge
and crest of curvature in cervical third -
remainder of outline is usually straight
 Lingual outline is generally convex, but with a
more cervically located crest of curvature than
is present on permanent molars.
Dr. Rooban Thavarajah

11. MESIAL ASPECT
 2 mesial cusps and mesial marginal ridge make
up occlusal outline.
 MP cusp is more generous in height and size
than is MB cusp – hence - at occlusal,
marginal ridge is relatively short.
 Cervical line is slightly curved toward occlusal
surface
Dr. Rooban Thavarajah

12. MESIAL ASPECT
Dr. Rooban Thavarajah

13. DISTAL ASPECT
 Smaller than mesial surface.
 As buccal surface tapers toward distal,
much of it is visible from this aspect.
 DB cusp is more prominent than small DL
cusp
Dr. Rooban Thavarajah

14. DISTAL ASPECT
 Distal marginal ridge is less pronounced
than is mesial.
 Mesial cusps actually provide occlusal
outline from this aspect.
Dr. Rooban Thavarajah

15. DISTAL ASPECT
 Cervical ridge is not so prominent in
buccal outline as it is from mesial aspect.
 Cervical line is straight to slightly curved
occlusally.
Dr. Rooban Thavarajah

16. OCCLUSAL ASPECT
 Crown outline converges Lingually, distally
 Rectangular in shape- short side- marginal
ridges
 Fossa: Central, mesial and distal triangular
fossa
 Ridges: Mesial, distal marginal ridge, Oblique
 Pit: central, mesial, distal
Dr. Rooban Thavarajah

17. OCCLUSAL ASPECT
Dr. Rooban Thavarajah

18. OCCLUSAL ASPECT
 Grooves: central, Buccal developmental, distal
developmental, disto-occlusal, supplemental
 Major cusps : Mesiolingual & Mesiobuccal
 Minor cusp: Distobuccal cusp
 If 4 cusp 2 buccal & 2 lingual
Dr. Rooban Thavarajah

19. ROOTS
 Roots Trifurcated
 2 buccal & 1 lingual
 Long, slender very flared
 Lingual root is largest
 Mesiobuccal next largest
 Distobuccal is shortest & straightest
Dr. Rooban Thavarajah

20. Dr. Rooban Thavarajah

21. Dr. Rooban Thavarajah
Maxillary Second Molar
 Buccal aspect
 ~ to permanent 1st
molar, but smaller
 2 buccal cusp with well defined DG
 Larger than 1st
molar
 Palatal
 3 cusps- MP – large, DP, Cusp of Carabelli
 Separated by 2 DG
 3 roots seen

22. Dr. Rooban Thavarajah
 Proximal : ~ to first molar
 Occlusal
 Resembles 1st
permanent molar
 Rhomboidal in shape
 4 or 5 cups
 Fossa: Central, MT, DT
 Pit: central, mesial, distal
 Ridge: MMR, DMR, Oblique ridge
 Groove: central, BDG< DDG, PDG

23. Dr. Rooban Thavarajah