1. Permanent Mandibular Molars

2. Introduction
Larger than the premolars in all dimensions, except occluso-cervically
Four or five major cusps
Two lingual cusps about same size*
Two roots: mesial and distal

3. Introduction… Wider M-D than F-L*
Rectangular/pentagonal occlusal outline
Rhomboidal proximal outline

4. Permanent Mandibular First Molar

5. General Characteristics
First permanent tooth to erupt
6th tooth from midline
Universal #19 and #30
Largest, strongest tooth in mandibular arch

6. General characteristics…
Five cusps: MB, ML, DL, DB, D (largest to smallest)
Two roots: mesial (larger) and distal
Pentagonal occlusal outline

7. Development Timeline:
Initial calcification: at birth*
Enamel completed: 2½ - 3 years
Eruption: years
Root completed: years

8. Facial View Buccal surface - largest surface of any tooth
Trapezoidal geometric form
Portions of all five cusps visible from this view

9. Facial view, mesial outline:
Mesial HOC at junction of occlusal and middle thirds
Flat or slightly concave cervical to the HOC
Dip in CE line over bifurcation

10. Facial view, distal outline:
Distal HOC slightly more cervical than mesial, in the middle third but close to the junction of occlusal and middle thirds
Generally more convex than mesial

11. Facial view, occlusal portion:
Three cusps (MB, DB, D) divided by two developmental grooves (MB and DB grooves)
Two facial pits: buccal (MB) and DB pits

12. Occlusal outline...
Buccogingival ridge running horizontally at cervical third area

13. Lingual View Crown tapers towards lingual
Two lingual cusps separated by lingual groove (no pit)
Lingual cusps are taller and sharper than buccal cusps
Lingual HOC at middle third

14. Mesial View Only two cusps visible (MB and ML)
Crown lingually inclined
Mesial marginal groove present
Facial HOC at cervical third
Lingual HOC at middle third

15. Mesial view... CE line more occlusal on lingual than buccal ~ 1 mm
Root length of lingual > buccal length
Mesial contact area buccal to marginal groove, at junction of occlusal and middle thirds

16. Distal View Distal marginal groove present
Shorter O-C than mesial surface
See more of occlusal surface
Portions of all five cusps visible

17. Distal view... Distal CE line almost flat
Distal contact area also buccal to distal marginal groove, usually in area of D cusp

18. Occlusal View Pentagonal (5-sided)
Tapers towards lingual (wider M-D towards facial)
Also tapers distally
Five cusps: MB, ML, DL, DB, D
Bucco-gingival ridge visible
Occlusal table shifted lingually – see more of buccal surface

19. Occlusal view… Five triangular ridges No true transverse ridges(?)
Three pits and three fossae: mesial, central, distal
Four primary developmental grooves: central, mesiobuccal, lingual, distobuccal

20. Root Form Two roots: mesial and distal Root depressions on both roots
Mesial root wider than distal
Two pulp canals: MB and ML canals
Distal root usually one canal

21. Anomalies: D cusp sometimes not prominent or missing
May exhibit three roots (MB, ML, D)

22. How To Tell Right From Left:
Broader mesial root
Presence of distal cusp
Wider F-L towards mesial (tapers to the distal)

23. Permanent Mandibular Second Molar

24. General Characteristics
Arch position: 7th from midline
Universal #18 and #31
More symmetrical than first molar*
Four cusps, less complex than first

25. Development Timeline:
Initial calcification: 2½ - 3 years
Enamel completed: years
Eruption: years
Root completed: years

26. Facial View Shorter and narrower than first molar
Mesial and distal outlines similar to first
Two buccal cusps, more similar in size, separated by buccal groove
Buccogingival ridge present

27. Lingual View
Two lingual cusps, similar in size, separated by lingual groove
Mesial HOC at junction of occlusal and middle third
Distal HOC at middle third

28. Mesial View Similar to first molar Facial HOC at cervical third
Lingual HOC at middle third
Mesial contact area buccal to marginal groove

29. Distal View No distal cusp Less taper towards distal than first molar
Distal contact area centered F-L, in the middle third O-C

30. Occlusal View Rectangular/pentagonal outline
More symmetrical and simple than first molar*
Less lingual taper than first
Slightly more supplementary anatomy than first
MB bulge
Four cusps: MB, DB, ML, DL

31. Occlusal view… Two transverse ridges
Three fossae and three pits: mesial, central, distal
Three primary developmental grooves: central, buccal, lingual (form a pattern)

32. Root Form Similar to first, except closer together
Mesial broader than distal

33. How To Tell Second From First:
Four cusps on second, five on first
+ groove pattern on second
Roots closer together on second
More supplemental anatomy on second

34. How To Tell Right From Left:
Broader mesial root
MB bulge
Distal contour more convex than mesial

35. Incline planes:

36. Permanent Mandibular Third Molar

37. General Characteristics:
Arch position: 8th from midline
Universal #17 and #32
Extremely variable, but always M-D dimension wider than F-L

38. Development Timeline:
Initial calcification: years
Enamel completed: years
Eruption: years
Root completed: years

39. Crown Form Two basic types More secondary grooves
Similar to 2nd molar, 4 cusps
Similar to 1st molar, 5 cusps
More secondary grooves
Shortest O-C of any mandibular tooth

40. Root Form Extremely variable Most commonly two-rooted
Crown:root ratio closer to 1:1
Roots almost as short as maxillary 3rds

41. Anomalies:
Often congenitally missing or impacted

42. How To Distinguish Third Molar:
Shorter roots
Occlusal table has more secondary grooves
Narrower occlusal table
No distal contact wear facet

43. How To Tell Right From Left:
F-L dimension wider towards mesial
If two roots: mesial broader than distal
Distal more convex than mesial
No distal contact wear facet

44. Tooth ID

50. Project 2

55. Questions???