1. DENTAL ANATOMY FOR THE ENT RESIDENT Hedyeh Javidnia, PGY2
November 7, 2008

2. Objectives Dental Anatomy Odontogenesis Types of Dentition
. .
Dental Anatomy
Odontogenesis
Types of Dentition
Tooth Surfaces
Mandibular & Maxillary Anatomy

3. Dental Anatomy Anatomy of a tooth.
a. Anatomical crown- portion of tooth covered with enamel
Anatomic crown

4. Dental Anatomy b. Clinical crown- visible part of
tooth above the gum line.
Anatomical crown
Clinical crown

5. Dental Anatomy
c. Root
(1) Part of tooth embedded in the alveolar process and covered by cementum.

6. Dental Anatomy d. Apex- tapered end of root tip.
e. Apical foramen-opening at the root tip.

7. Dental Anatomy Tissues of the tooth. a. Enamel
Makes up anatomic crown.
Hardest material in the human body
Incapable of remodeling and repair.

8. Enamel

9. Dental Anatomy b. Dentin (1) Makes up bulk of tooth.
(2) Covered by enamel on crown and cementum on the root.
(3) Not as hard as enamel.
(4) Exposed dentin is often sensitive to cold, hot, air, and touch (via dentinal tubules).

10. Dentin
Enamel
Dentinal Tubules

11. Dental Anatomy c. Cementum (1) Covers root of tooth.
(2) Overlies the dentin and joins the enamel at the cemento-enamel junction (CEJ).
(3) Primary function is to anchor the tooth to the bony socket with attachment fibers.

12. Dentin
Enamel
Dentinal Tubules
Cementum

13. Dental Anatomy
d. Pulp
(1) Made up of blood vessels and nerves entering through the apical foramen.
(2) Contains connective tissue, which aids interchange between pulp and dentin.

14. Dentin
Enamel
Dentinal Tubules
Cementum
Pulp

15. Dental Anatomy 4. Periodontium a. Alveolar process.
(1) Bone extensions of the maxillae and mandible that supports the teeth.
(2) Cortical plate is the dense outer layer of bone covering the spongy (cancellous) bone

16. Dentin
Enamel
Dentinal Tubules
Cementum
Pulp
Alveolar Process
Cortical Plate
Spongy Bone

17. Dental Anatomy b. Periodontal ligaments.
Dense connective fibrous tissues that connect teeth to the alveolar bone.
One end is embedded in cementum and other end in bone.
Supports and protects the tooth from normal shock.

18. Dentin
Enamel
Dentinal Tubules
Cementum
Pulp
Alveolar Process
Cortical Plate
Spongy Bone
Periodontal Ligaments

19. Dental Anatomy
c. Gingiva - surrounds the teeth and covers the alveolar process.

20. Dentin
Enamel
Dentinal Tubules
Cementum
Pulp
Alveolar Process
Cortical Plate
Spongy Bone
Periodontal Ligaments
Gingiva

21. Odontogenesis Bud Stage Cap Stage Bell Stage
D and E. Dentinogenesis and
amelogenesis
Crown formation
Root Formation
Eruption

22. A. Bud Stage
Intramembranous
ossification
Meckel’s
cartilage
Bud stage is characterized by rounded, localized growth of epithelium surrounded by proliferating mesenchymal cells, which are packed closely beneath and around the epithelial buds

23. B. Cap Stage
Vestibular lamina
When the appropriate depth is reached, the basal layer at the tip of the dental lamina thickens, forming a concavity.

24. C. Bell Stage
Dental lamina
Outer dental
epithelium
Inner dental
epithelium
Dental papilla
Dental follicle
Cervical loop
Continued growth leads to bell stage, where the enamel organ resembles a
bell with deepening of the epithelium over the dental papilla
Continuation of histodifferentiation (Inner dental epithelium - ameloblasts and
Dental papilla - odontoblasts)

25. D. Amelogenesis
Ameloblasts
First layer of enamel
Dentin
Odontoblasts
At the same time or soon after the first layer of dentin (mantle dentin) is formed,
the inner dental epithelial cells differentiate into ameloblasts and secrete enamel
proteins.
The ameloblasts will then start laying down organic matrix of
enamel against the newly formed dentinal surface. The enamel matrix will
mineralize immediately and form the first layer of enamel. The formation of
enamel is called amelogenesis.

26. E. Dentinogenesis
Dentin is formed by odontoblasts that differentiate from ectomesenchymal cells of dental papilla with influence from the inner dental epithelium
Differentiation of odontoblasts is mediated by expression of signaling molecules and growth factors in the inner dental epithelial cells

27. F. Crown Formation
Growth areas of developing crown. Growth at cusp tip, intercuspal region, and cervical region
Incremental pattern of dentin and enamel formation from initiation to completion

28. G. Root Formation
Hertwig’s epithelial
root sheath
Development of root begins after the enamel and dentin formation has reached the future cementoenamel junction
Epithelial cells of the inner and outer dental epithelium proliferate from the cervical loop of the enamel organ to form the Hertwig’s epithelial root sheath. The root sheath determines if a tooth has single or multiple roots, is short or long, or is curved ir straight

29. Epithelial Cell Rests of Malassez
Inner dental epithelium
Outer dental epithelium
Hertwig’s epithelial
root sheath
Stratum intermedium
Eventually the root sheath will fragment to form several discrete clusters
of epithelial cells known as epithelial cell rests of malassez. These will persist in adults within the periodontal ligament
The epithelial rests appear as small clusters of epithelial cells which are located in the periodontal ligament adjacent to the surface of cementum. They are cellular residues of the embryonic structure known as Hertwig's epithelial root sheath.

30. H. Tooth Eruption and Development of supporting structures
Soon after root formation begins, tooth begins to erupt until it reaches its final position
While roots are forming, the supporting structures of tooth also develop – periodontal ligament and cementum
As the root sheath fragments, the dental follicle cells will penetrate between the epithelial cells and lie close to the newly formed root dentin
These cells will differentiate into cementoblasts, which will make cementum

31. REVIEW: Odontogenesis
Bud Stage
Cap Stage
Bell Stage
D and E. Dentinogenesis and
amelogenesis
Crown formation
Root Formation
Eruption

32. Types of Dentition 1. Deciduous (baby) teeth
a. Twenty ( 20) primary teeth.
b. Arches - maxillary and mandibular.
c. Quadrants - each arch divided in half.
(1) Maxillary right and left.
(2) Mandibular right and left.
Enamel is thinner, pulp is thicker

33. Deciduous Teeth d. Teeth in each quadrant. (1) Central incisor
(2) Lateral incisor
(3) Cuspid
(4) 1st molar
(5) 2nd molar

34. Deciduous Teeth f. Numbering system. (1) Alphabetical.
(2) Maxillary - patient’s right to left, “A” through “J”.
(3) Mandibular - patient’s left to right, “K” thru “T”. K L M N O P Q R S T A B C D F H I J E G
MAXILLARY
MANDIBULAR

35. Types of Dentition 2. Permanent teeth.L
2. Permanent teeth.
a. Thirty-two (32) permanent teeth.
b. Arches - maxillary & mandibular.

36. Permanent Teeth c. Quadrants. (1) Maxillary right and left.
(2) Mandibular right and left.

37. Permanent Teeth Teeth in each quadrant. (1) Central incisor.
(2) Lateral incisor.
(3) Cuspid (canine).

38. Permanent Teeth (4) 1st bicuspid (5) 2nd bicuspid (6) 1st molar
(7) 2nd molar
(8) 3rd molar
(wisdom tooth)

39. Tooth Surfaces 1. Facial - next to cheeks & lips.
a. Labial- anterior facial.
b. Buccal - posterior facial.
Lingual- next to tongue.
Mesial - towards midline, an imaginary line between central incisors.
Distal- away from midline.
Incisal- cutting edge of anterior teeth.
Occlusal- chewing surface of the posterior teeth.

40. Tooth Surfaces
7. Proximal surfaces mesial or distal surface of a tooth lying next to another tooth.
8. Interproximal space
(embrasure) - spaces between teeth, filled with hard and soft tissue (interdental papilla).

41. Tooth Surfaces
9. Cusps- pronounced elevations on the occlusal surfaces of a tooth terminating in a conical or rounded surface.

42. Anatomy of the Mandible

43. Anatomy of the Maxilla

44. The End!!