3. Surface anatomy ☻Surface anatomy: The tooth surface is not a flat surface, there are elevations and depressions. Each elevation and depression is described based on its location, shape and function.

4. Lobe. It is the primary center of calcification and growth formed during the crown development. Each tooth begins to develop from four lobes or more. Only some maxillary third molars have as few as 3 lobes. Peg- shaped maxillary lateral incisors and some supernumerary teeth have less than three lobes THE MATURE FORMS OF LOBES ARE: 1. Mamelones 2.Cingulum 3.Cusps

5. A - Crown Elevations 1-Shape 2-Which teeth 3-Which surface 4-Which part of surface

6. 1. Mamelones: They are three small round projections of enamel present in the incisal third of newly erupted incisors. After normal use, the mamelones wear down into a flat edge.

7. 2.Cingulum: It is the round enlargement or bulge on the cervical third of lingual surface of the crown in anterior teeth (incisors and canines).

8. 3.Cusps: They are pyramidal projections on the incisal portion of the canine and on the occlusal surfaces of the premolars and molars.

9. (4)Tubercle. It is a small elevation. It is produced by excessive formation of enamel. Tubercle is noticed at the palatal surface of E and 6. Tubercle differs from cusp as it is formed of enamel only while cusp is formed of pulp horn covered by dentin and enamel. PULP HORN Cusp ENAMEL DENTIN Tubercle M B D P

10. (5) Ridge. It is a linear elevation on the different surfaces of the crown. A- R RR Ridges on the facial surface (Labial and Buccal): Labial Ridge:Buccal Ridge:Cervical Ridge: Found on the labial surfaces of canines. It is the result of greater development of middle labial lobe. Usually found on the buccal surfaces of the premolars. It is the result of greater development of middle buccal lobe. It is found on the cervical one third of the facial surfaces of all the teeth. Well developed in the (D) followed by (E).

11. B- R RR Ridges on the lingual surface: 1.Incisal Ridge:incisors 3.Lingual Ridge: canine 4.Marginal Ridge: Incisors,canine 2.Cusp Ridge:canine IR

12. C- R RR Ridges on the occlusal surface of posterior teeth: 1.Marginal Ridges 2.Triangular Ridges: 1 2 1 2

13. Triangular R. Cusp Tip M M RD M R Cusp Ridges MBC MLC DLC DBC

14. 3.Transverse Lower premolars 4.Oblique Ridge: (E, 6,7 may be D, 8) Remember that all teeth either anterior or posterior have cervical ridge and two marginal ridges (mesial and distal one).

15. B- Crown Depressions :

16. I- LINEAR DEPRESSIONS: 1- DEVELOPMENTAL GROOVE: 1- DEVELOPMENTAL GROOVE: It is narrow and sharply defined. short or long, denoting union of primary lobes. May be present on all surfaces of all teeth.

17. They are s ss small, irregularly placed auxiliary grooves. Branches from developmental grooves. Found usually on occlusal surfaces. They do not denote union of primary lobes. The t tt third molars followed by second permanent molars are characterized by high number of supplemental grooves. 2- SUPPLEMENTAL GROOVES: 2- SUPPLEMENTAL GROOVES: _6_6 6 _7_7 8 _8_8 7

18. It is found in the bottom of developmental groove. Results from incomplete union of the primary lobes. It is a fault in enamel. 3- FISSURE: 3- FISSURE: It is a broad U shaped d dd depression or valley on the occlusal surfaces of posterior teeth. Its inclines meet in a developmental groove and extend to the cusp tips. SULCUS: Cusp tip Dentin Enamel Fissure Developmental groove

19. II- CIRCUMSCRIBED DEPRESSIONS It is a s ss small depression or concavity. Found in both anterior and posterior teeth. Its name is derived from its place: 1- FOSSA:

20. a- LINGUAL FOSSA: Found Found on the lingual surfaces of anterior teeth. a- LINGUAL FOSSA: Found on the lingual surfaces of anterior teeth. LF canine incisor LF

21. b- MESIAL AND DISTAL TRIANGULAR FOSSA: Found Found on the occlusal surfaces of posterior teeth mesial and distal to the marginal ridges. b- MESIAL AND DISTAL TRIANGULAR FOSSA: Found on the occlusal surfaces of posterior teeth mesial and distal to the marginal ridges. MTF DTF

22. c- CENTRAL FOSSA: Found on occlusal surfaces of molars. They are formed by the converging of ridges terminating at a central point where there is the junction of grooves. CF CP

23. a- TRUE (DEVELOPMENTAL)PITS: These are small pinpoint depression. present at the junction / or at the ends of the developmental grooves. They may be found at the bottom of the central fossa (central pit) or at the bottom of the mesial and distal triangular fossae (mesial and distal pits). 2- PITS : b- FAULT PIT Usually develops as a result of i ii incomplete formation of enamel. It is l ll located at the end of the buccal developmental grooves of the lower molars or palatal developmental grooves of the upper molars and upper lateral incisor. c.p. d.p. m.p. p.p. b.p.

24. Socket Crypt Socket and crypt - Socket : is a bony space in mandible or maxilla supporting root(s) of erupted tooth. - Crypt : is a bony space in mandible or maxilla containing the developing tooth.