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Premolars
General Characteristics & 
Functions: 
• 2 premolars per quadrant 
• At least 2 cusps, buccal cusp always larger 
• Distal...
General Characteristics & Functions: 
• ‘Transitional tooth’ during chewing, or 
mastication 
• It has properties of both ...
Permanent Maxillary 
First Premolars
General morphology 
• From buccal aspect, crown resembles maxillary canine 
• except that mesial slope is longer than dist...
Principal identifying features 
• Two roots, buccal and palatal (tend to curve distally) 
• Two pulp horns and two pulp ca...
Buccal view features 
• Widest mesiodistally (of all premolars) 
• Mesial and distal contact – cervical to junction of 
oc...
Lingual view features 
• Lingual surface is rounded in all 
directions and smaller than buccal 
surface 
• Lingual cusp of...
Proximal view features 
• Mesial developmental depression 
extending to the root 
• CEJ curvature deeper and more occlusal...
Occlusal view features 
• Outline resembles a hexagon 
• Wider buccolingually than mesiodistally 
• Buccal ridge is promin...
Occlusal table components 
• Four buccal cusp ridges descend from the 
buccal cusp tip (buccal, lingual, mesial and 
dista...
Occlusal table components 
• Transverse ridge (buccal + lingual triangular ridge) 
• Long central groove extending mesiodi...
Permanent Maxillary 
Second Premolars
Chronology 
Initial calcification : 2-2.5 years 
Completion of crown : 6-7 years 
Eruption : 10-12 years 
Completion of ro...
Maxillary 2nd Premolar (15 & 
25) 
• 5th Tooth from midline of maxilla. 
• Maxillary 1st& 2nd premolar resemble 
each othe...
Description 
• Less angular, more rounded crown 
• Single root flattened mesiodistally 
• Smaller crown cervico-oclusally ...
Buccal aspect
Buccal Aspect 
• Shorter cusp, lest pointed 
• Mesial slope of buccal cusp ridge is usually 
shorter than the distal slope...
Lingual aspect
Lingual Aspect 
• Lingual cusp is longer 
• Therefore crown is longer on lingual 
side
Mesial aspect
Mesial Aspect 
• Shorter Cusp , with the buccal and lingual cusp 
more nearly the same length 
• Greater distance between ...
Distal aspect
Distal Aspect 
• Distal root depression is deeper than the mesial 
depression ( opposite in maxillary 1st premolar; 
depre...
Occlusal aspect
Occlusal Aspect 
• Outline of crown is more rounded/oval rather than 
angular 
• Central developmental groove is shorter a...
Permanent Mandibular 
First Premolar
Chronology 
• Initial calcification: 1 ¾ - 2 Years 
• Crown completion: 5 – 6 Years 
• Eruption: 10 – 12 Years 
• Root com...
Tooth Identification 
Universal Numbering System 
Palmer Notation Method
Tooth Identification 
International/FDI system
Buccal Aspect 
• A large pointed buccal cusp is 
seen 
• Mesiobuccal cusp ridge is shorter 
than the distobuccal cusp ridg...
Lingual Aspect 
• Crown tapers lingually 
• Lingual cusp is non functional as 
it is small and pointed 
• Some lingual cus...
Mesial Aspect 
• Lingual cusp is around two third 
the size of the buccal cusp 
• Extreme lingual slope is seen at 
the me...
Distal Aspect 
• Distal marginal ridge is higher 
compared to the mesial 
marginal ridge and does not 
have extreme lingua...
Occlusal Aspect 
• Two depressions 
(mesial and distal fossae) 
seen on the occlusal surface 
• Mesiolingual depression 
a...
Root 
• Single root 
• On the mesial aspect of the root, a 
deep developmental groove is seen 
• On the distal aspect, a s...
Permanent Mandibular 
Second Premolar
Chronology 
• Initial calcification : 2 ¼ - 2 ½ years 
• Completion of crown : 6-7 yrs 
• Eruption : 11-12 years 
• Comple...
Buccal side 
R 
-Resembles 1st 
premolar 
-Larger crown 
-Shorter and less 
pointed buccal cusps 
-Broader
Lingual Side 
R -Lingual cusp is smaller than 
buccal cusp but it is larger than 
mandibular first premolar 
lingual cusp ...
Mesial Side 
• Dimension at cervical 
3rd > occlusal 2rd 
• Mesio-lingual cusp is 
longer and sharper than 
the mesiobucca...
Distal Side 
- Crown is narrower 
distally than mesially 
- Cervical line curves 
occlusally 
R
Variation 
• May have 2 cusps 
• Root may be partially bifurcated (Rare)
View Maxillary 1st Premolar Maxillary 2nd Premolar 
Occlusal Larger Smaller 
Edgy crown More rounded crown 
Buccal cusp lo...
Mandibular 1st vs 2nd premolar 
Traits Mandibular first premolar Mandibular second 
premolar 
Buccal cusp and buccal cusp ...
Maxillary vs Mandibular 
Traits Maxillary Mandibular 
Buccal ridge More prominent Less prominent 
Buccal and lingual 
cusp...
Premolars
Premolars
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Morphology of premolars

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Premolars

  1. 1. Premolars
  2. 2. General Characteristics & Functions: • 2 premolars per quadrant • At least 2 cusps, buccal cusp always larger • Distal to the canines • Succedaneous • Shorter crown than anterior teeth
  3. 3. General Characteristics & Functions: • ‘Transitional tooth’ during chewing, or mastication • It has properties of both the anterior canines and posterior molars • Assist molars in grinding, and canines in tearing • Food can be transferred from the canines -- premolars -- molars for grinding • Support facial muscles (aesthetics and speech)
  4. 4. Permanent Maxillary First Premolars
  5. 5. General morphology • From buccal aspect, crown resembles maxillary canine • except that mesial slope is longer than distal slope • Distinct depression on mesial surface, extending from cervical half of crown to root bifurcation • mesial developmental depression / fossa canina / canine fossa • *assumed to be caused by pressure from earlier completed crown of maxillary first canine • The only premolar with two roots • *maxillary second premolars may also have double roots • Buccal cusp larger than palatal cusp • From occlusal aspect, buccal side wider than palatal side • Two cusps separated by deep central groove
  6. 6. Principal identifying features • Two roots, buccal and palatal (tend to curve distally) • Two pulp horns and two pulp canals • Two sharply defined cusps (buccal larger than palatal) • Mesial developmental depression • Mesial slope of buccal cusp longer than distal slope • Palatal cusp tilts slightly mesially • Occlusal outline more angular than maxillary second premolar
  7. 7. Buccal view features • Widest mesiodistally (of all premolars) • Mesial and distal contact – cervical to junction of occlusal and middle third • Mesial outline more rounded • Imbrication lines and perikymata • Mesial slope of buccal cusp is longer than distal slope (helps to distinguish right from left)
  8. 8. Lingual view features • Lingual surface is rounded in all directions and smaller than buccal surface • Lingual cusp offset towards mesial • Mesial cusp slope of lingual cusp is shorter than distal cusp slope
  9. 9. Proximal view features • Mesial developmental depression extending to the root • CEJ curvature deeper and more occlusal on the mesial surface compared to distal surface • Distal surface is similar to mesial (except it does not have a depression) • More of occlusal surface shows because distal marginal ridge is more cervical than mesial marginal ridge
  10. 10. Occlusal view features • Outline resembles a hexagon • Wider buccolingually than mesiodistally • Buccal ridge is prominent on buccal margin • Lingual margin of occlusal outline is almost a semicircle • Lingual part narrower mesiodistally than buccal part
  11. 11. Occlusal table components • Four buccal cusp ridges descend from the buccal cusp tip (buccal, lingual, mesial and distal) • Four buccal-inclined cuspal planes (mesiobuccal, mesiolingual, distobuccal and distolingual) • Four lingual cusp ridges • Four lingual-inclined cuspal planes
  12. 12. Occlusal table components • Transverse ridge (buccal + lingual triangular ridge) • Long central groove extending mesiodistally (dividing tooth buccolingually) • Marginal grooves (mesial and distal ) • Triangular grooves (mesiobuccal, distobuccal, mesiolingual and distolingual) • Two triangular fossa (mesial and distal)
  13. 13. Permanent Maxillary Second Premolars
  14. 14. Chronology Initial calcification : 2-2.5 years Completion of crown : 6-7 years Eruption : 10-12 years Completion of root : 12-14 years
  15. 15. Maxillary 2nd Premolar (15 & 25) • 5th Tooth from midline of maxilla. • Maxillary 1st& 2nd premolar resemble each other closely. • Therefore comparisons are made in relation to maxillary 1st Premolar to be able to distinguish the features between the two.
  16. 16. Description • Less angular, more rounded crown • Single root flattened mesiodistally • Smaller crown cervico-oclusally and mesiodistally, (it also may be larger in those dimensions • Root length slightly greater than maxillary 1st premolar • No canine fossa
  17. 17. Buccal aspect
  18. 18. Buccal Aspect • Shorter cusp, lest pointed • Mesial slope of buccal cusp ridge is usually shorter than the distal slope (opposite for 1st premolar) • Crown and root are thicker at the cervical portion (not a rule)
  19. 19. Lingual aspect
  20. 20. Lingual Aspect • Lingual cusp is longer • Therefore crown is longer on lingual side
  21. 21. Mesial aspect
  22. 22. Mesial Aspect • Shorter Cusp , with the buccal and lingual cusp more nearly the same length • Greater distance between the cusp tips widens the occlusal surface buccolingually • Shallow developmental groove on the single tapered root (not found on the Maxillary 1st premolar) • No developmental groove crossing the mesial marginal ridge is evident.
  23. 23. Distal aspect
  24. 24. Distal Aspect • Distal root depression is deeper than the mesial depression ( opposite in maxillary 1st premolar; depression on the mesial surface of the root)
  25. 25. Occlusal aspect
  26. 26. Occlusal Aspect • Outline of crown is more rounded/oval rather than angular • Central developmental groove is shorter and more irregular; tendency toward multiple supplementary grooves radiating from the central groove • Supplementary grooves terminate in shallow depressions in the enamel that may extend to the cusp ridges. • Irregular and wrinkled occlusal surface
  27. 27. Permanent Mandibular First Premolar
  28. 28. Chronology • Initial calcification: 1 ¾ - 2 Years • Crown completion: 5 – 6 Years • Eruption: 10 – 12 Years • Root completion: 12 – 13 Years
  29. 29. Tooth Identification Universal Numbering System Palmer Notation Method
  30. 30. Tooth Identification International/FDI system
  31. 31. Buccal Aspect • A large pointed buccal cusp is seen • Mesiobuccal cusp ridge is shorter than the distobuccal cusp ridge (similar to that of a canine) • Concavity is seen occasionally at the mesial and distal slope of the buccal cusp
  32. 32. Lingual Aspect • Crown tapers lingually • Lingual cusp is non functional as it is small and pointed • Some lingual cusp is even shorter than the cingulum of the maxillary canine • Mesiolingual developmental groove is seen between the mesiobuccal and lingual lobe
  33. 33. Mesial Aspect • Lingual cusp is around two third the size of the buccal cusp • Extreme lingual slope is seen at the mesial marginal ridge • Between the mesial marginal ridge and the mesiolingual cusp ridge is the mesiolingual developmental groove • Mesial contact area is in the middle third
  34. 34. Distal Aspect • Distal marginal ridge is higher compared to the mesial marginal ridge and does not have extreme lingual slope • The cervical line curvature is less curved
  35. 35. Occlusal Aspect • Two depressions (mesial and distal fossae) seen on the occlusal surface • Mesiolingual depression and mesiolingual developmental groove commonly seen • Lingual cusp tip is shifted mesially
  36. 36. Root • Single root • On the mesial aspect of the root, a deep developmental groove is seen • On the distal aspect, a shallow depression without any developmental groove is present
  37. 37. Permanent Mandibular Second Premolar
  38. 38. Chronology • Initial calcification : 2 ¼ - 2 ½ years • Completion of crown : 6-7 yrs • Eruption : 11-12 years • Completion of root: 13-14 yrs
  39. 39. Buccal side R -Resembles 1st premolar -Larger crown -Shorter and less pointed buccal cusps -Broader
  40. 40. Lingual Side R -Lingual cusp is smaller than buccal cusp but it is larger than mandibular first premolar lingual cusp -Occlusal surface of buccal cusp can be seen
  41. 41. Mesial Side • Dimension at cervical 3rd > occlusal 2rd • Mesio-lingual cusp is longer and sharper than the mesiobuccal cusp R
  42. 42. Distal Side - Crown is narrower distally than mesially - Cervical line curves occlusally R
  43. 43. Variation • May have 2 cusps • Root may be partially bifurcated (Rare)
  44. 44. View Maxillary 1st Premolar Maxillary 2nd Premolar Occlusal Larger Smaller Edgy crown More rounded crown Buccal cusp longer than lingual Two cusps same length Long central groove Short central groove More supplement grooves Groove interrupts mesial marginal ridge Mesial marginal ridge not interrupted Mesial/d istal Shorter root Longer root Bifurcation with root trunk Single-rooted Mesial developmental depression (canine fossa) Convex mesial surface Buccal Mesial slope longer Distal slope longer
  45. 45. Mandibular 1st vs 2nd premolar Traits Mandibular first premolar Mandibular second premolar Buccal cusp and buccal cusp ridge More prominent and longer Less prominent and shorter buccal cusp Lingual cusp One, nonfunctional -very small Usually 2 and functional -longer Lingual convergence Present, mesiolingual appears to be pushed in Little taper Lingual groove Mesiolingual groove present Lingual groove between the 2 lingual cusps Marginal ridge Mesial marginal ridge lower and parallel to the buccal triangular ridge Distal marginal ridge lower and mesial, and distal ridges are more horizontal Lingual crown tilt Severe lingual crown tilt less Crown outline Diamond shaped Square / Round Central groove and Definite transverse ridge and central transverse ridge groove unlikely 3 cusp type has no transverse ridge and ‘Y’ groove pattern
  46. 46. Maxillary vs Mandibular Traits Maxillary Mandibular Buccal ridge More prominent Less prominent Buccal and lingual cusp height difference Not very prominent More difference Lingual tilt of crown Crown aligned over the root Crown tilts lingual relative to the root Crown width Wider bucco lingually Less oblong buccolingually Crown shape Oval or rectangular Square or round
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Morphology of premolars

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