05. Maxillary Molars (CD) - Dentition

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05. Maxillary Molars (CD) - Dentition

  1. 1. Surface Anatomy of Maxillary Permanent Molars
  2. 2. BUCCAL PALATAL OCCLUSAL MESIAL DISTAL
  3. 3. BUCCAL SURFACE * The geometric outline: Trapezoidal with the small uneven side present cervically * Outline form : D Mesial outline: Nearly straight till the contact area at the junction of the occlusal and middle 1/3 Distal outline: Convex till the contact area at the middle 1/3 M
  4. 4. Occlusal outline: presenting mesio-buccal & disto-buccal cusps. D Cervical outline: Irregular and slightly convex toward the root M
  5. 5. Surface anatomy: * Convex buccal surface with the crest of curvature at the cervical 1/3 representing Cervical ridge. D *Buccal groove may terminate by buccal pit. Mesio-buccal cusp is broader, shorter and less sharp than the disto-buccal cusp M
  6. 6. P The Roots: * Root trunk: 4 millimeters DB MB *3 roots are seen from the buccal surface which are widely diverge . * The axis of the roots are inclined D distally * Deep developmental groove extend on root trunk M
  7. 7. LINGUAL SURFACE * It is the reverse of the buccal surface with No lingual convergence Mesial outline: Nearly straight and form with the mesial slope of the ML cusp M Distal outline: Convex and form semicircle with the distal slope of the DL cusp D
  8. 8. Occlusal outline: ML cusp is the largest and longest cusp. DL cusp is spheroidal M Cervical outline: Irregular and slightly convex toward the root D
  9. 9. Surface anatomy: *Convex lingual surface with the crest of curvature at the middle 1/3. *Tubercle of Carabelli is found on the lingual surface of ML cusp. *Lingual developmental groove ends with palatal pit . M D
  10. 10. MESIAL SURFACE The geometric outline: Trapezoidal with small uneven side occlusally. Buccal outline: * Convex with the B maximum convexity at the cervical 1/3 denoting cervical ridge. Concave at the middle 1/3 denoting the* termination of the buccal developmental .groove Convex at the occlusal 1/3 representing* .circumscribed MB cusp L
  11. 11. Lingual outline: * Convex with the crest of curvature at the middle 1/3. B * The lingual outline dips inward to illustrate the tubercle. L
  12. 12. Occlusal outline: * Represented by ML , MB cusps * Irregular MMR which curve cervically. Cervical outline: Irregular and convex occlusally Anatomical landmarks Mesial contact area at the junction between middle and occlusal 1/3, buccal to the center
  13. 13. DISTAL ASPECT MESIAL ASPECT *Distal Convergence * Wider mesial surface *Convex distal surface * Flat mesial surface * Mesial marginal ridge *Distal MR curved less curved cervically Continue
  14. 14. MESIAL ASPECT DISTAL ASPECT MB P P DB *Straight cervical line *Cervical line convex occlusally *Root trunk= 5mm *Root trunk = 3mm *3 roots are seen *2 roots are seen
  15. 15. OCCLUSAL SURFACE The geometric outline: B D M Rhomboidal. L > B & M > D surfaces. Note : * Disto-buccal convergence. * ML, BD angles are obtuse. *MB, DL angles are acute .The ML & DB cusps are found at the obtuse angles. L
  16. 16. B Anatomical landmarks: Elevations: *4 cusps with 4 triangular ridges and D tubercle.The ML is the largest cusp followed by MB,then DL and lastly DB which is the smallest cusp. Oblique ridge between ML&DB* .triangular ridges MMR and DMR* M L
  17. 17. B Anatomical landmarks: Depression: D M (major fossae ( central and distal 2* Minor fossae ( mesial and distal 2* (.triangular fossae *Developmental grooves (Buccal, Central, transverse groove of oblique ridge, Distal oblique groove and Lingual groove(. L
  18. 18. Pulp cavity☻ ►Pulp Chamber: The pulp chamber is broader Bucco-lingually than mesio.distally There is pulp horn beneatheach cusp - The floor is apical to the cervical line.
  19. 19. Pulp cavity☻ :Root Canals► -3 main root canals. -MB root may have 2 root canals Note: Cervical cross section: Rhomboidal Mid root section: MB root canal ( Oval- Kidney( DB root canal (Round-Oval( P root canal ( Round- Oval(
  20. 20. Enumerate the names of the following ?elevations and depression DMR-1 Oblique ridge-2 Distal linear fossa-3 Central fossa- 4 Buccal groove- 5 Mesial triangular fossa- 6 Lingual groove- 7
  21. 21. PALATAL BUCCAL OCCLUSAL MESIAL DISTAL
  22. 22. BUCCAL SURFACE 6 7 M D D M in 7 the crown is smaller, narrower & shorter .The MB cusp is larger and longer than DB cusp ,the roots are close & parallel .The root trunk is longer than in 6
  23. 23. LINGUAL SURFACE 6 7 D M D *The crown converge lingually.The DL cusp is smaller in 7 .It may be missed ( 3 - cusp type) No cusp of carabelli in 7 *
  24. 24. MESIAL SURFACE 7 D 6 M * No cusp of carabelli in 7 MB and P roots in 7 are confines within the* BL outlines of the crown D
  25. 25. DISTAL ASPECT Distal Convergence * ** Convex distal surface ***Distal MR curved cervically B L
  26. 26. OCCLUSAL ASPECT B B D M L cusp type 4 outline typical to 6 Disto- lingual convergence No tubercle of carabelli M L cusp type 3 shape typical to 8 No disto-lingual cusp, No lingual or distal oblique grooves
  27. 27. Pulp cavity☻ ►Pulp Chamber: The pulp chamber is broader Bucco-lingually than mesio.distally There is pulp horn beneatheach cusp - The floor is apical to the cervical line.
  28. 28. Pulp cavity☻ :Root Canals► -3 main root canals. -MB root may have 2 root canals Note: Cervical cross section: Rhomboidal Mid root section: MB root canal ( Oval- Kidney) DB root canal (Round-Oval) P root canal ( Round- Oval)
  29. 29. PALATAL BUCCAL OCCLUSAL MESIAL DISTAL
  30. 30. BUCCAL SURFACE MB cusp is wider and longer than DB cusp The roots are often fused making one large short root
  31. 31. LINGUAL ASPECT Usually one large lingual cusp without lingual groove
  32. 32. MESIAL SURFACE Characterized by fusion of the roots and the bifurcation in the apical 1/3
  33. 33. DISTAL SURFACE Convex surface with no* contact area *The distal surface short and narrow. So most of the occlusal surface is seen.
  34. 34. OCCLUSAL ASPECT cusp type 3 shape is typical to 7 No disto-lingual cusp, No lingual or distal oblique grooves cusp type 4 outline typical to 6 There are disto- lingual cusp, Lingual groove .and oblique ridge
  35. 35. OCCLUSAL SURFACE :Notes The occlusal surface of 8 has- 1 numerous supplemental grooves The pulp cavity showed great- 2 variation in the size and shape The pulp chamber of 8 is larger than- 3 other molars because it is younger than other molars by 9-11 years

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