Morphology of Human Deciduous Maxillary Molar Tooth


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

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Morphology of Human Deciduous Maxillary Molar Tooth

  1. 1. Prof. Rooban Thavarajah Tooth Morphology Lecture Series Dr. Rooban Thavarajah
  2. 2. Dr. Rooban Thavarajah Deciduous Dentition Maxillary Molars
  3. 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. 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. 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. 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. 7. PALATAL ASPECT Dr. Rooban Thavarajah
  8. 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. 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. 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. 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. 12. MESIAL ASPECT Dr. Rooban Thavarajah
  13. 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. 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. 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. 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. 17. OCCLUSAL ASPECT Dr. Rooban Thavarajah
  18. 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. 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. 20. Dr. Rooban Thavarajah
  21. 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. 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. 23. Dr. Rooban Thavarajah