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PERMANENT MANDIBULAR MOLARS

PERMANENT MANDIBULAR MOLARS. MANDIBULAR 1 st MOLAR. the largest and the strongest mandibular molars not considered succedaneous first permanent molars to erupt = six year molars 5 cusps 2 roots D &M (3 canals: 1-D, 2-M). UNIQUE FUTURES. largest mesiodistal crown dimension of any tooth

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PERMANENT MANDIBULAR MOLARS

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  1. PERMANENT MANDIBULAR MOLARS

  2. MANDIBULAR 1st MOLAR • the largest and the strongest mandibular molars • not considered succedaneous • first permanent molars to erupt=six year molars • 5 cusps • 2 roots D &M (3 canals: 1-D, 2-M)

  3. UNIQUE FUTURES • largest mesiodistal crown dimension of any tooth • he occlusocervical and faciolingual dimensions of the first molar are greater than any other mandibular molar • Mandibular first molars have three facial cusps as do some mandibular third molars • the longest roots of any molar • the greatest mesiodistal root separation of any molar • The mesial root has the greatest faciolingual dimension of any root in the mouth

  4. Buccal view • The mesiofacial (mesiobuccal) cusp is the largest, widest, and highest of the 3 facial cusps • The facial (buccal) cervical line is nearly straight but there can be enamel that dips cervically nearly into the furcation • The two lingual cusps (mesiolingual and distolingual) are visible because they are taller cusps

  5. The mesialroot averaged 1 mm longer than the distal root • Both roots have an overall distal inclination • The distalroot is straighter than the mesial root

  6. Lingual view • The greater height of the lingual cusps hide the facial cusps • portions of the proximal surfaces are visible from a lingual view • The lingualcervical line is nearly straight

  7. Mesial view • Two cusps can be seen (ML & MB) • Only one root can be seen (FL length twice MD) • The mesialcervical line curves occlusally • The lingualheight of contour (area of greatest convexity) has been located in the middle third of the crown • The faciolingual (buccolingual) crown, root, cusps dimension is greater M than D • The two major mesial cusps (mesiofacial and mesiolingual) are larger than the distal cusps

  8. Distal view • Distolingual cusp is largest • distalproximal contact has been located facial to the crown center (Fuller/Denehy/Schulein; Renner), centered over the root • From a distal view, more of the facial surface can be seen than from a mesial view because the crown tapers distally • More of the occlusal surface is visible from a distal view than mesial view because the distal surface is shorter occlusocervically

  9. Occlusal view • 5 cusps. All of them functional • The mesiofacial cusp is the largest cusp • The crown tapers lingually • The outline form has been described as pentagonal

  10. There are four developmental grooves on the occlusal surface: central; mesiofacial (mesiobuccal); distofacial (distobuccal); and lingual • There are three fossae: central; mesial; and distal • The central developmental groove has a zigzag mesiodistal form • The central development groove forms a “Y” shape with the lingual developmental groove. This is one of the principal occlusal groove patterns

  11. MANDIBULAR 2nd MOLAR • Resemble 1st B and L except there no 5th cusp or D cusp • Rooth shorter, closer more D inclined • 4 cusp nearly equal size

  12. UNIQUE FUTURES • F the roots curve laterally and then toward each other in a manner that resembles the handles of a pair of pliers a unique form shared with only the maxillary first molar • a MF prominence, a unique feature for mandibular molars • The D proximal contact is centered both FL and occlusocervically, a characteristic shared with four other teeth (Max lateral incisor, Max canine, Max1st molar and Max2ndmolar)

  13. Facial view • Shorter MD and cervicoolcclusally than 1st • Just 2 B cusps • Roots shorter, closer, more D inclined

  14. Lingual view • Little if any of the mesial and distal surfaces are visible lingually due to the limited lingual crown taper • The lingualgroove may terminate on the occlusal surface or extend onto the lingual surface in the occlusal third (L pit) • Contact areas lower D and M

  15. Mesial view • The FL dimension of the Mroot is greater than the distal, but less rhan 1st molar • mesialproximal contact- similar to the 1st molar, slightly to the facial of the center of the crown • The cervical line is more cervically positioned on the facial surface than lingual

  16. Distal view • No Distal cusp • Little of the facial surface is visible from a distal view • proximal contact has been located at the center of the crown • Distalroot is narrower than M

  17. Occlusal view • The outline form has been described as rectangular • A number of supplemental grooves are present, “wrinkled” appearance • mesiobuccal cusp is normally the largest cusp, but almost equal in size • developmental grooves: facial; central; and lingual, forming a cross • 3 fossae, 3 B, L & M pits+grooves may present

  18. MANDIBULAR 3RD MOLAR • more varied in size and shape than all other teeth except the maxillary third molars • small apical-occlusal dimension • the D half of the crown has a noticeably shorter than the M half • crown resembles a mandibular second molar with 4 cusps • Some mandibular third molars have three facial cusps • The mesiolingual cusp is the largest of all the cusps. The lingual cusps are often larger and longer than the facial cusps and more rounded

  19. The roots are usually pointed, inclined D, often fused, short • There may be multiple roots and as many as 8 roots • The facial surface is very convex and the tooth has a bulbous form • occlusaloutline form is often ovoid • The occlusal table is distinctly ovoid in outline form and highly restricted • The occlusal surface is quite “wrinkled” due to numerous supplemental grooves and ridges

  20. MANDIBULAR MOLAR ROOTS • 2 roots: 1-M, 2 – D with single root trunk • M root – longer and stronger, curves M then turns D near apex • Root trunk short and grooved on B and L surfaces

  21. CHARCTERISTICS

  22. PULP CAVITY

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