1. Maxillary Premolars Dental Health Proper Tooth Contours =
Healthy Occlusion (Function)
& Periodontal Health

3. MAXILLARY PREMOLARS

4. GENERAL CHARACTERISTICS OF PREMOLARS
Location and number
Names and Identification
Shapes and functions

5. LOCATION AND NUMBER Distal to canines and mesial to molars Total of 8
4 maxillary(2 per quadrant)
4 mandibular(2 per quadrant)

6. NAMES AND IDENTIFICATION
Maxillary 1st premolars #5, #12
Maxillary 2nd premolars #4, #13
Mandibular 1st premolars #28, #21
Mandibular 2nd premolars #29, #20
Premolar teeth succeed primary molars

7. SHAPES AND FUNCTIONS
Buccal cusp of maxillary and mandibular 1st premolars are sharp and aid in prehension and tearing
2nd premolars have more rounded cusps and function more like molars than canines

8. SHAPES AND FUNCTIONS (CON’T)
Crowns of premolars are shorter than anterior teeth and root length is similar to molars
Marginal ridges are part of occlusal surface

9. MAXILLARY FIRST PREMOLAR
General characteristics
Development
Views
Axial inclination and occlusion
Roots
Pulp spaces

10. GENERAL CHARACTERISTICS
2 major cusps of approximately equal size
Facial
Lingual

11. GENERAL CHARACTERISTICS(CON’T)
Among posterior teeth:
Greater relative buccolingual width
Broader contact areas
Proximal contact areas more nearly the same level
Less curvature of CEJ mesially and distally
Shorter Crown

12. DEVELOPMENT First calcification 1.5 to 1.75 yrs
Enamel completed to 7 yrs
Eruption to 11 yrs
Root completed to 13 yrs
Develops from four lobes
Usually has 2 roots and 2 root canals

13. BUCCAL VIEW
Basic form of a trapezoid (occlusal, mesial, distal, cervical)
Little curvature to CEJ
Resembles canine
Mesial outline is concave below contact

14. BUCCAL VIEW (CON’T)
Distal outline has a broader curvature, but straight at the CEJ
Mesial slope of facial cusp is straighter and larger than distal and may exhibit a notch

15. BUCCAL VIEW (CON’T)
Mesial and distal contact areas are at a more equal level than anterior teeth and are found in the middle 1/3rd
Strong development of the middle buccal lobe—continuous bulge from cusp tip to CEJ is the buccal ridge
Mesial and distal developmental depression may be seen

16. BUCCAL VIEW (CON’T)
Presence of strong mesial and distal line angles are the result of the development of corresponding lobes
Mesio- and disto-occlusal point angles are prominent and bulge compared to the cervical portion (type trait)

17. BUCCAL VIEW (CON’T)
The cusp tip divides the occlusal portion into a mesial cusp ridge and a distal cusp ridge
Curvature cervical to the proximal contacts is less on the distal cusp ridge

18. LINGUAL VIEW
The cusp tip divides the occlusal portion into a mesial cusp ridge and a distal cusp ridge
Curvature cervical to the proximal contacts is less on the distal cusp ridge

19. LINGUAL VIEW (CON’T)
Proximal outline at CEJ is flat or concave, but lingual cusp is convex
CEJ is regular and flat
Lingual cusp is shorter than buccal with cusp tip positioned mesially

20. LINGUAL VIEW (CON’T)
Both cusp ridges are more curved and form less distinct line angles than on buccal
Distal outline is convex or flat; mesial outline shows a concavity cervical to the proximal contact area

21. MESIAL VIEW Basic shape is trapezoidal(mesial and distal)
CEJ curvature is less than on anterior teeth
CEJ curvature is greater on the mesial surface than the distal
Lingual cusp is shorter

22. MESIAL VIEW(CON’T)
Buccal and lingual line angles set the limits of the proximal surfaces
Buccal outline shows height of contour in the cervical 1/3rd or at the junction of the cervical and middle 1/3rd
Lingual outline is smooth, convex with height of contour in the middle 1/3rd

23. MESIAL VIEW (CON’T) Both cusps are long and sharp
Mesial marginal ridge is at the junction of the occlusal and middle 1/3rd
Mesial developmental depression is found cervical to the mesial contact area
Presence of mesial marginal groove (type trait)

24. DISTAL VIEW
Distal marginal groove does not cross the distal marginal ridge Usually no distal depression in root surface for cervical portion of the crown Other characteristics are similar to the mesial surface

25. OCCLUSAL VIEW Outline form is hexagonal (type trait)
Facial cusp is wider and longer
Cusp ridges of the buccal cusp are the facial, lingual, mesial, and distal

26. OCCLUSAL VIEW (CON’T)
Lingual ridge of the buccal cusp and buccal ridge of the lingual cusp are triangular ridges
2 triangular ridges form a transverse ridge
2 distinct buccal line angles

27. OCCLUSAL VIEW (CON’T) Lingual line angles are less distinct
Mesial and distal cusp ridges are continuous with the marginal ridges and surround the occlusal surface
Lingual cusp tip is positioned mesial to the buccal cusp

28. OCCLUSAL VIEW (CON’T) Central groove Mesial marginal groove
Mesiobuccal triangular groove
Distobuccal triangular groove
Mesial triangular fossa
Distal triangular fossa
Buccal and lingual triangular ridges
Outline tapers lingually

29. AXIAL INCLINATION Proximal view: 5°-to lingual (roots)
Facial view: 9°-to distal (roots)

30. OCCLUSION
The maxillary 1st premolar occludes with the mandibular 1st and 2nd premolar

31. ROOTS Buccal root resembles the canine(only shorter
Usually has 2 roots, but may have one root with 1 or 2 canals; this results in a buccal and lingual terminal root
Mesial developmental groove runs from the bifurcation to the CEJ and on to the crown as a concavity

32. PULP SPACES
The root canals show the same variation as the root-with approximately 20% having one canal
From a buccal view—the pulp cavity resembles that of a canine

33. MAXILLARY SECOND PREMOLAR

34. GENERAL CHARACTERISTICS
Similar to first premolar
Usually has a single root
More rounded from all aspects
Cusp tips are less pointed and shorter
Lingual cusp is longer
Occlusal is more axial and more supplementary grooves

35. DEVELOPMENT First calcification 2.25 yrs Enamel completed 6-7 yrs
Eruption yrs
Root completed yrs

36. BUCCAL VIEW
Very similar to the 1st premolar, but more rounded

37. LINGUAL VIEW
Lingual cusp is taller than on the 1st premolar and mesial surface is much less concave

38. PROXIMAL VIEWS
Lingual cusp is longer than on 1st premolar(relative to buccal cusp)
Cusps are more rounded
Mesial marginal groove does not extend onto the mesial surface
Less curvature of CEJ

39. OCCLUSAL VIEW More rounded line angles More supplemental grooves
Proximal contacts are positioned facially on the maxillary premolars

40. OCCLUSAL VIEW (CON’T)
Mesial and distal proximal contacts are found in the middle 1/3rd occlusogingivally
Facial embrasure is less deep than the greater lingual embrasure due to the position of the proximal contact and the narrower lingual cusp

41. AXIAL INCLINATION Proximal view: 6°--to lingual (roots)
Facial view: 5°--to distal (roots)

42. OCCLUSION
The maxillary 2nd premolar occludes with the mandibular 2nd premolar and the mesiobuccal cusp of the mandibular 1st molar

43. ROOTS The root resembles the single rooted maxillary 1st premolar
Both proximal root surfaces have longitudinal grooves

44. PULP CAVITY
The pulp cavity is similar to the single rooted 1st premolar with approximately 60% having one root canal