1. Permanent Mandibular Incisors

2. Introduction Simplest, least variable teeth
Centrals slightly smaller than laterals
Crowns are narrower M-D relative to the I-C length
Presence of three mam mamelons

3. Permanent Mandibular Central Incisor
Arch position: adjacent to midline
Universal #24 and #25
Narrowest M-D width and smallest crown size*
Very symmetrical crown*

4. Development Timeline:
Initial calcification: months
Enamel completed: years
Eruption: years
Root completion: 9 years

5. Labial View Incisal 2/3 generally flat to slightly convex
Height of contour at cervical third
Geometric form: trapezoidal

6. Labial View - mesial outline:
Even straight taper towards cervical
MI angle angular
Mesial HOC at the incisal third

7. Labial View - distal outline:
Almost a mirror image of mesial outline
Difficult to distinguish M from D

8. Labial View - incisal outline:
Perpendicular to long axis
One wear facet only anterior tooth that opposes one tooth*

9. Lingual View Surface relatively smooth Marginal ridges indistinct
Lingual fossa shallow
No pits or grooves

10. Lingual view:
Diminished cingulum
Height of contour at cervical third

11. Mesial View Labial outline fairly straight at incisal 2/3
Facial and lingual heights of contour at cervical third

12. Mesial view: Incisal edge lingual to long axis of tooth*
Incisal edge slopes facially
HOC at incisal third

13. Distal View Similar to mesial
CE line curvature slightly less than mesial
HOC also at same level -incisal third (unique)

14. Incisal View Wider F-L than M-D Diamond-shaped outline
See more of facial than lingual
M and D halves symmetrical
Incisal edge is perpendicular to F-L bisector*

15. Root Normally single and straight, occasionally bifurcated
Gradual taper to sharp apex

16. Root: Wider F-L, narrower M-D Slight root concavities M and D
Cross-section at cervical: rounded rectangle

17. Permanent Mandibular Lateral Incisor

18. General Characteristics
Arch position: 2nd tooth from midline
Universal #23 and #26
Very similar in form to mandibular central

19. Development Timeline:
Initial calcification: months
Enamel completed: years
Eruption: years
Root completion: 10 years

20. Labial View
Very similar to mandibular central except DI angle slightly more rounded
M and D heights of contour at incisal third, with D slightly more cervical

21. Lingual View Similar to mandibular central
Cingulum slightly offset to distal

22. Incisal View Incisal edge curves towards lingual in distal portion*
Crown appears twisted on root
Distal HOC more lingual than mesial
Cingulum appears offset to distal
Two facets of wear

23. Mesial and Distal Views
Similar to mandibular central except:
Distal incisal corner visible from mesial*
Mesial View

24. M and D views: Mesial CE line curvature slightly more than distal
Distal View
Mesial View

25. Root Similar to mandibular central except slightly wider, thicker
Root concavities present with distal more pronounced
Occasional bifurcated root

26. How To Tell Mandibular Central from Lateral:
Distal corner of incisal edge twisted lingually on lateral*
One wear facet on central, two facets on lateral

27. Lateral vs central: DI corner of lateral very slightly more rounded
Cingulum slightly offset to distal

28. How to tell right from left:
Very difficult with mandibular centrals

29. Right from left: Laterals: lingual twist of distal incisal edge*
DI slightly more rounded
Cingulum offset distally

30. Tooth ID

35. Wax Quiz

39. Dimensions: 10: 0 - 0.1 mm off 9: 0.2 - 0.4 mm off 8: 0.5 - 0.9 mm off
Grade
10: mm off
9: mm off
8: mm off
7: mm off (re-do)
6: greater than 1.5 mm off (re-do)
Note: No credit given for grade of 6 or 7

40. Axial Contours: Surface contours as compared to the original
Facial, lingual, mesial, distal, incisal, occlusal
Line angles, point angles

41. Occlusal surface: Only posterior teeth!
Cusps, marginal ridges, cusp ridges, grooves, etc as compared with original

42. CE Line:
Position, contour, smoothness, transition from root to crown

43. Surface Texture:
Smoothness, without visible scratches or irregular surfaces
Wax additions should be seamless

44. Surface Polish: Degree of surface shine
No foreign coating on the surface, e.g. Speedshine, die lube, etc.

45. What to turn in…
Note: Paperclip envelope to sheet - DON’T seal envelope

46. Questions????