1 / 49

Permanent Maxillary Molars

Permanent Maxillary Molars. Maxillary First Molar. General Characteristics. Arch position: 6th tooth from midline Universal #3 and #14 Mesially, contacts primary 2nd molar and later 2nd premolar Largest tooth in maxillary arch Largest crown in mouth

latricia
Télécharger la présentation

Permanent Maxillary Molars

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Permanent Maxillary Molars

  2. Maxillary First Molar

  3. General Characteristics • Arch position: 6th tooth from midline • Universal #3 and #14 • Mesially, contacts primary 2nd molar and later 2nd premolar • Largest tooth in maxillary arch • Largest crown in mouth • Least variable in anatomic form among max molars

  4. General form: • Three roots: L, MB, DB • Slightly wider F-L than M-D • Trapezoidal geometric form F/L and proximal views • Occlusal view: rhomboidal geometric form (described as 5-sided) mesial facial

  5. Development Timeline: • Initial calcification: at birth* • Enamel completed: 3 - 4 years • Eruption: 6 - 7 years • Root completed: 9 - 10 years

  6. Facial view, mesial outline: • Mesial HOC at junction of occlusal and middle thirds • Outline relatively flat cervical to mesial HOC • M-D > O-C dimension

  7. Facial view, distal outline: • Distal HOC at middle third • Entire distal outline convex • Disto-occlusal angle more rounded than mesio-occlusal angle • Distal surface visible from facial view (rhomboidal effect)

  8. Facial view, cervical line: • Oftentimes a V-shape dip CE line pointing towards buccal bifurcation

  9. Facial view, occlusal portion: • MB and DB cusps separated by buccal groove • MB cusp wider, DB cusp tip sharper* (sharpest of 4 cusps) • ML cusp visible between MB and DB cusps

  10. More facial… • Buccal groove usually ends midway O-C in a buccal pit • Bucco-gingival ridge runs horizontally, more prominent towards mesial • Facial HOC at cervical third

  11. Lingual View • DLG separates larger ML cusp from smaller DL cusp • DLG oftentimes terminates in lingual pit • Lingual groove midway M-D • M-D width as wide or wider lingually than facially*

  12. Lingual view… Georg Carabelli court dentist to Austrian emperor (1842 A.D.) • Cusp of Carabelli* • Lingual surface of ML cusp • Varies in size: non-existent to prominent • Lingual HOC at middle third • Lingual root depression*

  13. Mesial view, facial outline: • Buccal HOC at cervical third (bucco-gingival ridge) • Facial surface fairly flat from HOC to cusp tip

  14. Mesial view, lingual outline: • Lingual HOC at middle third • Overall convex curvature • Palatal root apex is lingual to the crown

  15. Mesial view, occlusal outline: • Only MB and ML cusps visible • Mesial marginal groove usually present, midway of marginal ridge • Mesial contact area situated buccal to mesial groove, at junction of occlusal and middle thirds

  16. Distal View • More of occlusal surfaces visible • All four cusp tips visible • Distal marginal groove usually present, midway of marginal ridge • Pronounced distal cervical crown/root concavity*

  17. Distal view… • More of facial surface visible, but less of lingual surface (rhomboidal form) • Distal contact area located midway F-L, more cervical than mesial contact (middle third) Mesial view

  18. Occlusal View • Rhomboidal geometric form • Acute MB and DL corners • Obtuse DB and ML corners • 5-sided (pentagonal) • Largest F-L dimension of any tooth*

  19. Occlusal view… • F-L and M-D dimensions more nearly similar* • M-D width as wide or wider lingually than facially* • Four major cusps: ML, MB, DB, DL (largest to smallest) • Cusp triangle: MB, DB, ML (trigon)

  20. Occlusal view… • Transverse ridge • Triangular ridges of MB and ML cusps • Oblique ridge • Triangular ridges of DB and ML cusps (distal cusp ridge?) • About same height as the marginal ridges* • Mesial 2/3 looks like max premolar

  21. Occlusal view… • Three pits: mesial, central, distal • Three primary developmental grooves: central, buccal, distolingual • Four fossae: mesial, central, distal, distolingual

  22. Root Form • Root trunk with trifurcation: • Lingual root: • Largest, longest • Wider M-D than F-L* • MB root • 2nd largest • Apex in line with MB cusp tip* • DB root • Smallest of three

  23. Root form... • DB root area may have pronounced cervical concavity* • MB and DB root forms look like “plier handles” • MB root could have two pulp canals (70% possibility) • Root depression, lingual surface of lingual root

  24. How To Tell Right From Left: • Distolingual groove • Cusp of Carabelli on ML cusp • Broader MB root than DB root • MB prominence of facial surface

  25. Maxillary Second Molar

  26. General Characteristics • Arch position: 7th from midline • Universal #2 and #15 • Wider F-L than M-D • Similar to 1st, except smaller • Smaller DL cusp

  27. Development Timeline: • Initial calcification: 2½ - 3 years • Enamel completed: 7 - 8 years • Eruption: 12 - 13 years • Root completed: 14 - 16 years

  28. Facial View • Narrower M-D than 1st • M-D > O-C dimension • MB cusp larger than DB • Buccal groove more distally located than 1st • MB root tip in line with buccal groove*

  29. Lingual View • Smaller DL cusp than 1st • Lingual groove more distally located • No Cusp of Carabelli

  30. Mesial and Distal Views • Similar to 1st except shorter O-C • Facial HOC at cervical third • Lingual HOC at middle third • Mesial HOC at junction of occlusal-middle • Distal HOC slightly more cervical

  31. Occlusal View • Narrower M-D than F-L • Tapers lingually • Two major crown forms: - Rhomboidal - Heart-shaped (diminished DL cusp)

  32. Root Form • MB and DB roots closer than 1st • MB apex in line with buccal groove* • No lingual root depression

  33. How To Tell First From Second: • Occlusal view of first less rhomboidal than second • Cusp of Carabelli only on first • M-D and F-L dimensions more similar with first, narrower M-D with second*

  34. First from second... • MB root apex in line with MB cusp tip with first, in line with buccal groove with second*

  35. Maxillary Third Molar

  36. General Characteristics • Arch position: 8th from midline • Universal #1 and #16 • No distal contact area • Only maxillary tooth that has single opposing tooth* • Smallest of all molars - shortest O-C dimension of any tooth*

  37. Development Timeline: • Initial calcification: 7 - 9 years • Enamel completed: 12 - 16 years • Eruption: 17 - 21 years • Root completed: 18 - 25 years

  38. Crown Form • Most variable of maxillary posteriors • Heart-shape most common • Diminished or absent DL cusp • 3-cusp form (L, MB, DB cusps) • Still wider F-L than M-D • Occlusal table more constricted • No distal contact wear facet

  39. Root Form • Three roots, partially or fully fused • Roots much shorter than 1st and 2nd, crown:root ratio closer to 1:1 • Roots shorter than any other tooth (other than mandibular 3rds)

  40. How To Distinguish a Third: • Shorter root: Crown to root ratio nearly 1:1* • Roots usually fused • More supplemental occlusal grooves* • Heart-shape occlusal outline, narrower occlusal table

  41. How To Tell Right From Left: • MB root larger than DB root • MB prominence of facial surface • DLG, if present • Contact area wear facet only on mesial

  42. TOOTH ID

  43. That’s All, Folks!

More Related