mandibular second molars

for second professional BDS students,NBDE,FCPS 1,MFDS

1. Mandibular second molar DR Jameel kifayatullah Demonstrator oral biology kcd 24/05/2017

2. Permanent mandibular second molar

3. PERMANANENT MANDIBULAR SECOND MOLAR Arch position: 7 th from midline mesial contact : Permanent mandibular first molar distal contact : permanent mandibular third molar if/when it erupts

4. General form and function Resembles the first molar in many respects though it is more symmetrical Smaller in all dimensions than mandibular first molar. Least complicated occlusal design Only 4 cusps present No distobuccal groove No distal cusp Grinding function

5. Cusps 4 cusps of nearly equal size in mandibular second molar Mandibular first molar : 5 cusps of differing sizes 4 developmental lobes:MB,DB,ML,DL lobes

6. Developmental table Initiation of calcification:2.5-3 years Completion of enamel: 7-8 years Eruption: 11-13 years Completion of root: 14-15 years

7. Buccal aspect

8. Buccal aspect Trapezoidal Shorter occlusogingivally and narrower mesiodistally Mesial margin: concave from cervical line to contact area and convex occlusally Distal margin: more rounded or convex Cervical line: curvature less like that of first molar ,some may exhibit dip over bifuraction area

9. Buccal aspect Occlusal Margin divided into two equal halves by the buccal groove the two buccal cusps Mesiobuccal and distobuccal cusps nearly equal in length

10. Buccal aspect Buccal groove ends in buccal pit/ may fade out in middle third No distobuccal groove Buccogingival ridge in cervical third horizontally running more prominent in mesial portion

11. BUCCOCERVICAL RIDGE

12. Buccal aspect Mesial contact : junction of occlusal and middle third Distal contact: slightly cervical ,but still at junction of occlusal and middle third

13. Lingual Aspect

14. LINGUAL ASPECT TRAPEZOIDAL Shorter occlusocervically and narrower mesiodistally than first molar Mesial,distal and cervical outlines similar to lingual surface of mandibular first molar i.e concave mesial margin from contact area to cervical line and then occlusally convex Convex distal margin Shorter cervical line mesiodistally located at more occlusal level than buccal surface and irregular to nearly straight

15. Lingual aspect OCCLUSAL OUTLINE: divided into half by the lingual groove Only the two lingual cusps(ML and DL) visible Crown convergence lingually ---part of mesial and distal surfaces seen from this view. The height of contour is in middle third

16. Mesial aspect Mesial contact area ovoid whereas mesial contact area of mandibular first molar is round/slightly ovoid. Crown wider buccolingually on mesial aspect than distal aspect(right from left distinguished)

17. Distal aspect No distal cusp contour No distobuccal groove Less convergence of buccal surface towards the distal. Distal surface is about the same size as mesial and little of buccal surface visible. Contact area centered on the distal surface both buccolingually and occlusogingivally . Irregular wider BL than occlusogingivally

18. Lingual tilt

19. Occlusal surface

20. Occlusal table

21. Occlusal view Rectangular outline 4 cusps two buccal two lingual Occlusal surface of second considerably different from that of first because no distal cusp and all cusps are of equal size. Cross shaped groove pattern: well defined central grooove crossed by buccal groove and lingual groove.

22. Occlusal view 3 occlusal pits; Central pit in central fossa mesial pit in mesial triangular fossa distal pit in distal triangular fossa Two transverse ridges

23. Occlusal table

24. Transverse ridge

25. occlusion

26. roots 2 roots i.e mesial and distal Smaller ,shorter and less divergent in placement than those of first molar Root branches closer together Root trunk of second molar longer than that of first Distal angulation of roots

27. Mandibular second molar roots

28. Roots of mandibular second molar

29. Root