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

2. Mandibular Premolars

3. Mandibular Premolars
Mandibular 1st Premolars / Mandibular 2nd Premolars
General Characteristics
Development
Appearance
Buccal view
Lingual view
Mesial view
Distal view
Occlusal view
Axial inclination
Root and Pulp Space

4. Mandibular Premolars

5. Mandibular First Premolar

6. Mandibular First Premolar
General Characteristics
Buccal cusp is long and sharp
BL dimensions similar to canine
Occlusal surface slopes lingually
Proximal view resembles a canine

7. Mandibular First Premolar
Development
First Calcification: Yrs
Enamel Completed: 5-6 Yrs
Eruption: Yrs
Root Completed : Yrs
4 Lobes

8. Mandibular First Premolar
Buccal View
Well developed middle labial lobe (buccal cusp ridge)
Mesial cuspal ridge shorter than distal cuspal ridge
General shape of trapezoid
CEJ shows little curvature
Proximals are flat at cervical and convex at proximal contact areas

9. Mandibular First Premolar
Buccal View (continued)
Distal is slightly more rounded
Cusp tip is positioned to mesial
Proximal contacts are located in occlusal 1/3**

10. Mandibular First Premolar
Lingual View
Lingual cusp very small (type trait)
Cervical slope of occlusal surface
Concave areas above CEJ mesial and distal
Has mesiolingual developmental groove and strong transverse ridge

11. Mandibular First Premolar
Mesial View
Crown outline is rhomboid
Like all mandibular posterior teeth
Buccal cusp tip over center of root
Buccal height of contour in gingival 1/3**
Lingual height of contour in middle 1/3**
CEJ has only a slight curvature
Mesial marginal ridge is lower than distal marginal ridge

12. Mandibular 1st Premolar
Distal View
Distal marginal ridge is higher than mesial marginal ridge
No developmental groove
Buccolingual concavity above CEJ
CEJ less curvature than mesial

13. Mandibular 1st Premolar
Occlusal View
Diamond-shaped
Prominent buccal ridge
Mesio- and distobuccal line angles are prominent
Broad proximal contact areas
Small lingual cusp

14. Mandibular First Premolar
Occlusal View (cont.)
Highly developed marginal ridges
Mesial and distal fossae are present, usually with pits (“snake eyes”)
Mesiolingual developmental groove (type trait)
Much variation
Strong transverse ridge

15. Mandibular First Premolar
Axial Inclination
Root inclination to lingual 9°
Root inclination to distal = 6°

16. Mandibular First Premolar
Occlusion
Mandibular 1st premolar occludes with the maxillary canine and maxillary 1st premolar

17. Mandibular First Premolar
Roots and Pulp Space
Usually has 1 root; resembles canine root (oval shape)
Root may have longitudinal groove
Pulp chamber follows external form
Usually one canal

18. Mandibular Second Premolar

19. Mandibular Second Premolar

20. Mandibular Second Premolar
General Characteristics
Differs in occlusal design, especially the lingual cusp(s)
Larger root than mandibular 1st premolar

21. Mandibular Second Premolar
Development
1s Calcification: Yrs
Enamel Completed: 6-7 Yrs
Eruption: Yrs
Root Completed: Yrs

22. Mandibular Second Premolar
Buccal View
Shorter buccal cusp
Similar to first premolar: mesial and distal cusp ridges are not as sharp

23. Mandibular Second Premolar
Lingual View
Prominent lingual cusp(s)
Lingual cusp(s) shorter than buccal but wider and taller than lingual cusp of 1st premolar
Flat emergence angle
Lingual groove

24. Mandibular Second Premolar
Mesial View
Crown and root wider than 1st premolar
Larger lingual lobe development
May be 5 lobes
Marginal ridges perpendicular to long axis of tooth
No mesiolingual developmental groove

25. Mandibular Second Premolar
Distal View
Crown is Angled Lingually to Long Axis: True of all Posterior Teeth(Maxillary and Mandibular)
Lower Distal Marginal Ridge Than Marginal Ridge of Mesial

26. Mandibular Second Premolar
Occlusal View
3 Cusps(“Y” outline)
2 Cusps(“H” outline)
2 Cusps(“U” outline)
#29

27. Mandibular Second Premolar
Occlusal View:
“Y” configuration
Square outline
Central fossae
3 triangular ridges
Developmental grooves(mesial, distal, lingual, “Y”)
Triangular fossae(mesial, distal)
#20

28. Mandibular Second Premolar
Occlusal View:
“H” Configuration
Rounded outline
Some lingual convergence
Rounded distolingual line angles
One lingual cusp
Central developmental groove
Mesial and distal fossae

29. Mandibular Second Premolar
Occlusal View:
“U” Configuration
More rounded
Very round line angles
Central developmental groove
Mesial and distal fossae

30. Mandibular Second Premolar
Axial Inclination
Root inclination to facial = 9°
Root inclination to distal = 9°

31. Mandibular Second Premolar
Occlusion
The mandibular 2nd premolar occludes with the maxillary 1st premolar and the maxillary 2nd premolar

32. Mandibular Second Premolar
Root and Pulp Space
Larger root
Oval in cross-section
Root apex may deviate distally
Pulp cavity usually has two pulp horns and one canal
Canal is wider faciolingually