1. Oral Histology, Embryology & Genetics
Dent 5315/DH2215 February 19, 2008

3. Embryology in The News

4. Dentinogenesis - The Formation of Dentin
Root Formation
Dentin-Pulp Complex
Dentin Classification
Clinical Correlations

5. THE DENTIN-PULP COMPLEX
“Origins”

6. THE DENTIN-PULP COMPLEX
Dentin and pulp are related:
a. embryologically b. histologically c. functionally
dental papilla/pulp

7. THE DENTIN-PULP COMPLEX

8. THE DENTIN-PULP COMPLEX
Mature dentin-pulp complex
Note vascularity of pulp
“Subodontoblastic plexus of Raschkow” occupies cell-free zone of Weil (crown only)

9. THE DENTIN-PULP COMPLEX
Note: a. dentin tubules & odontoblastic processes
b. irregular mineralization fronts (arrows)

10. DENTIN CLASSIFICATION
Types of dentin: globular/interglobular

11. DENTIN CLASSIFICATION
Types of dentin:
Interglobular dentin is especially noticeable in vitamin D deficiency, high levels of fluoride, etc..

12. DENTIN CLASSIFICATION
Junction of primary & secondary dentin.

13. DENTIN CLASSIFICATION
Types of dentin:

14. DENTIN CLASSIFICATION
Types of dentin: reparative/tertiary dentin
What can initiate this type of dentin?
Exposed open tubules, caries, restorations, chemicals such as etching, etc.

15. ENAMEL vs DENTIN
Types of dentin: reparative/tertiary dentin
Note “S-shaped” tubules in coronal region
&
“dead tracts”

16. DENTIN CLASSIFICATION
Why does this tooth appear pink?
Typical radiographic appearance of internal root (dentin) resorption.

17. DENTIN CLASSIFICATION
Internal resorption with root perforation (arrow)
dentin tubules
“giant cells”

18. DENTIN CLASSIFICATION
Area of normal tubular dentin (arrow) & area osteodentin.
Note multinucleated giant cells resorbing both calcified reparative tissue & primary dentin.

19. DENTIN CLASSIFICATION
Types of dentin: inter & intra globular dentin
Inter = between
Intra = within

20. DENTIN CLASSIFICATION
Types of dentin: sclerotic/transparent dentin
Histopathology_of_dental_Dental_caries_1.ppt -

21. CLINICAL CORRELATIONS
How does a knowledge of dentin affect cavity preparation? a. amputation of odontoblastic processes
b. communication to pulp
c. placement of bases, pulp injury (heat, acid etch, etc.)
d. progression of caries bacteria
Cavity preparation in dentin

22. CLINICAL CORRELATIONS
“Rampant” Caries
Note areas of demineralization

23. Clinical Correlations
2. What makes dentin structure susceptible to caries?
Dentin has a tubular structure.
Caries can spread along DEJ.
Crystals dissolve at low pH produced by cariogenic bacteria.

24. CLINICAL CORRELATIONS
Horizontal clefting right angle to dentinal tubules.
Bacterial beading, coalescence, clefting typifies progression of dentinal caries.

25. CLINICAL CORRELATIONS
3. What is dentin hypersensitivity? Why is dentin sensitive?
Pain due to communication between outside environment & pulp.
3 Theories of dentin hypersensitivity. (Fig. 8-61)

26. CLINICAL CORRELATIONS
Dentin hypersensitivity
Loose/defective restoration
Dessication forces

27. CLINICAL CORRELATIONS
Product Evaluation