University of Palestine

1. University of Palestine College of Dentistry Human Dentition I Classification and Numbering System • Dr. Samir M. Ziara • B.D.S. (Alexandria Univ.) • D. D. P. H. Royal Collage of Surgeon (London) • M. Sc. P. H. Al-Quds Univ. • Diploma of H. Administration

2. Surface Anatomy of Permanent Teeth

3. Surface Anatomy of Permanent Teeth I, for incisor C, for canine I C P, for premolar P M I C P M M, for molar

4. Anterior teeth They are divided into: Incisors And Canines

5. Incisors There are four maxillary incisors and four mandibular incisors. ♥ Two central incisors contact with each other in the midline (mesially) and with the lateral incisors distally. ♥Two lateral incisors contact with the central incisor mesially and with the canine distally.

6. For easy teeth description We have to speak about : • Function (mastication (incising), esthetic, speaking). • Chronology. • Number of lobes (four lobes 3 labially and 1 lingually). • Geometric outline of the crown. • Outlines of the crown and root. • Surface anatomy of the crown and root. • Pulp cavity.

7. Chronology: • Enamel organ appearance. • Beginning of calcification. • Crown completed. • Eruption. • Root completed.

8. All teeth have 5 aspects 1 Distal Facial Lingual Mesial Incisal

9. 2 Lingual Mesial Distal Labial Incisal

10. 1 Labial Lingual Mesial Distal Incisal

11. 2 Labial Mesial Distal Lingual Incisal

12. Geometric outline of the crown Facial and lingual aspects have trapezoid out line. Smallest uneven side cervically.

13. Facial and lingual outlines of the crown As mentioned before It’s Trapezoid and is formed of Cervical outline (convex root wise) Distal outline (more convex) Mesial outline (convex) Sharp mesioincisal angle Rounded distoincisal angle Incisal (straight and may have mamelons) When?

14. ☺You have to note that 2 has two rounded angles but the distal angle is more. ☺1 has two sharp angles and straight out lines mesially and distally. D M

15. Outlines of the root • The mesial and distal outline of the root tapered to a pointed apex • The apex directed distally except the 1 it’s centralized on the long axis so extraction could be done by rotation movement Note: the apex of 1 is blunt.

16. Surface anatomy of the crown and root. Labial aspect • The crown surface is smooth and convex with maximum convexity at the cervical third (cervical ridge) Elevations: Depressions: • Shallow developmental grooves could be seen separating mamelons. • The root surface is smooth and convex

17. Lingual aspect • Elevations: • Marginal ridges (mesial and • distal) • Cingulum (cervically) • Incisal ridge cingulum Depressions: Lingual fossa Marginal ridges Incisal ridge

18. Note: • All elevations are more developed in upper teeth than in lower teeth. • So the fossae appear shallower in the lower teeth. • Lingual pit could be found in the 2 and should notice that all elevations are well developed than 1

19. ☺You have to notice that the lingual surface of all teeth is smaller in size than the labial due to the lingual convergence. This convergence of the teeth is to accommodate the larger arch size facially than lingually

20. Can you tell *which tooth *which aspect *which surface anatomical landmark 1 , labial aspest, cervical ridge. 2, lingual aspect, lingual pit. 2 , labial aspect, cervical ridge. 2, lingual aspect, cingulum, M&D marginal ridges

21. Geometric outline of the crown Proximal (mesial and distal) aspects have triangular outline Apex incisally. Base cervically. Note: the incisal ridge of 1 &2 inclined lingually. Why?

22. Mesial and distal Outlines It’s Triangular and formed of • Labial outline: convex with maximum convixity at the cervical third which represent ……. • Lingual outline: • convex incisally which represent……. • Concave at the middle which represent… • Convex cervically which represent……… • Cervical outline: Curves incisally.

23. Note: • The convexity of labial and lingual outlines are well developed in the upper teeth than lower teeth. Why? • The curvature of cervical lines in all teeth distally is less than mesially. The height of curvature decreased also from upper teeth to lower teeth

24. Outlines of the root Upper incisors: The outlines tapered from the cervical line to a blunt rounded apex Lower incisors: The outline are nearly straight from the cervical line to the middle third then tapered to a pointed apex

25. Surface anatomy of the crown and root. The crowns have smooth convex proximal surfaces. The contact areas present in the incisal third. Mesially, near the mesioincisal angle. distally, near the junction of incisal and middle thirds. Note: the contact areas mesially and distally are near to each other but still distal contact area present more cervically.

26. Roots They have convex smooth surfaces except lower incisors have longitudinal developmental depression which is deeper distally than mesially.

27. Incisal aspectOutline and surface anatomy Upper incisors: The outline is triangular in shape. The base is placed labially and apex lingually. The mesiodistal dimension(width) is greater than the labiolingual dimention (thickness). • Note: • The elevations and depressions in the crown lingually and labially appeared in this aspect. The crown is tapered lingually.

28. Lower incisors: The outline is diamond in shape. The labiolingual dimension Is greater than the mesiodistal dimension. • The incisal ridge of 2 tilted distally that allows the tooth to follow the dental arch curvature.

29. Pulp cavity. Pulp cavity is formed of: Pulp chamber that is present in the crown. Its outline follows the outline of the crown. In young teeth, it has pulp horns related to each mamelon Root canal that present in the root and follow its outline. The number of root canals in incisors is only one. The root canal ends in an apical foramen

30. Identify the tooth, the aspects and tell FOUR differences between the lateral and central incisor. Answer A- Upper P. central incisor. B- Upper P.lateral incisor Lingual aspect 1- Size. 2- The elevations and depressions 3- The incisal angles. B A 4- The root.

31. Identify the tooth, the aspect and the anatomical landmark. A 2, lingual aspect, long mesial marginal ridge, short distal marginal ridge. 1, mesial aspect, contact area, cervical line. A is for 2, incisal aspect, distally tilted cingulum. B B is for 1 , incisal aspect, lingual fossa.

32. Canine For easy teeth description let’s make a quick revision; • Function (mastication (tearing), esthetic). • Chronology. • Number of lobes (four lobes 3 labially and 1 lingually). • Geometric outline of the crown. • Outlines of the crown and root. • Surface anatomy of the crown and root. • Pulp cavity.

33. Chronology: • Enamel organ appearance. • Beginning of calcification. • Crown completed. • Eruption. • Root completed

34. Upper canine has 5 aspects: Labial Distal Lingual Mesial Incisal

35. Lower canine has 5 aspects: Distal Mesial Lingual Labial Incisal

36. Geometric outline of the crown Facial and lingual aspects have trapezoid out line. Smallest uneven side cervically.

37. Facial and Lingual Outlines of 3 It’s Trapezoid and formed of Mesial outline:, convex till the contact area (at the junction of I 1/3 and O 1/3) then continues as concave till the cusp tip. Distal outline: concave till the contact area (at the middle third) then continues as convex till the cusp tip. Cervical outline: convex root wise.

38. The mesial slope is shorter than the distal slope. The cusp tip pointed and on line with the long axis but slightly mesially deviated.

39. Facial and Lingual Outlines of 3 Mesial outline is convex. Mesial outline is straight. Both contact areas are more incisally so the crown appeared longer and thinner than 3 Contact areas are more cervically. Cusp tip is less pointed Cusp tip is more pointed

40. Outlines of the root • The mesial and distal outline of the root tapered to a pointed distally curved apex • The mesial and distal outline of the root tapered to a sharply pointed distally curved apex

41. Surface anatomy of the crown and root. Labial aspect Elevations: • It’s convexwith maximum convixity at the cervical ridge. • There is prominent ridge runs from the tip of the cusp toward the cervical margin (Labial ridge). The middle lobe is well developed giving the cusp Depressions: Shallow longitudinal depressions lie mesial and distal to the labial ridge. The root shows convex smooth surface

42. Lingual aspect Elevations: • Marginal ridges, cingulum, • Prominent lingual ridge that extend from the cusp tip till the cingulum in 3 while in 3 it’s restricted to the incisal third. Depressions: Lingual fossa that is divided into two fossae in 3 but still one in 3. • Note: • The elevations of lower canine are not well developed as the upper cingulum • The lingual surface is smaller in size than the labial surface due to the lingual convergence which accommodate ……….

43. Geometric outline of the crown Proximal aspects have triangular outline Apex of the triangle incisally. Note: the cusp tip of 3 centralized on the long axis or inclined labially. while the 3 cusp tip centralized or inclined lingually. The base cervically. Apex of the triangle incisally.

44. Mesial and distal Outlines of the crown It’s wedge in shape: Labial outlineis convex with the crest of curvature at the cervical third represent…… Lingual outlineis convex cervically represent... In the middle it’s straight due to presence of ridge …….. In the incisal third it’s convex again represent……

45. Cervical outline:curved incisally however, this curvature is less on the distal than the mesial. • Notes: • Lingual outline in the middle of 3 is concave rather than straight due to short lingual ridge.

46. Outlines of the root Upper canine: The outlines tapered from the cervical line to a blunt pointed apex. It’s apical third may curved labially. Lower canine: The outline are nearly straight from the cervical line to the middle third then tapered to a more pointed apex

47. Surface anatomy of the crown and root The crown surface is convex and smooth, except area cervical to the contact area shows flattening (mesial surface) or concavity (distal surface). Position of contact areas vary from mesial to distal of same tooth and vary from upper to lower canine…….identify their position as mentioned before.

48. The root surface is broad with longitudinal depression. The depression is shallower mesially than distally of same tooth and is shallower in upper canine than lower canine. Note: the depression in lower canine may be so deep causing bifurcation in the root. The bifurcation may be apically or extend up to cervical third.

49. Enumerate the names of the following elevations and depressions? Lingual ridge Cingulum. Distal marginal ridge Mesial marginal ridge. D.L.F M.L.F D.I.Ridge M.I.Ridge

50. Incisal aspect.Outline and surface anatomy The thickness is greater than the width. The labial surface appeared convex and even more than the incisors The cingulum forms a short arc. The elevations and depressions in the labial and lingual surfaces appeared in this aspect