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

15. The mesial and distal outline of the root tapered to a pointed apex Outlines of the root • 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. The crown surface is smooth and convex with maximum convexity at the cervical third (cervical ridge) Labial aspect 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.