This document discusses the junctions found in oral mucosa, including the muco-cutaneous junction, muco-gingival junction, and dento-gingival junction. It provides detailed information on the histology and development of the dento-gingival junction. Specifically, it describes the non-keratinized stratified squamous epithelial attachment to the tooth, the basal lamina, and the process of passive eruption by which the junction migrates along the tooth surface from enamel to cementum with age.

1. Menatalla M. Elhindawy

2. Junctions
in
Oral Mucosa

3. Oral Mucosa..
Keratinized Non-keratinized

4. Oral Mucosa..
I. Masticatory II. Lining III. Specialized

5. Junction..

6. Junctions in Oral Mucosa
I. Muco-cutaneous
II. Muco-gingival
III. Dento-gingival

7. Junctions in Oral Mucosa
I. Muco-cutaneous Junction.

8. Junctions in Oral Mucosa
I. Muco-cutaneous Junction.
 K. st. sq. epith.
 Lamina propira
 Thin k. st. sq. epith.
 Lamina propira
 Para k. st. sq. epith.
 Lamina propira
 Thick nonk. st. sq. epith.
 Lamina propira

9. Junctions in Oral Mucosa
I. Muco-cutaneous Junction.

10. Junctions in Oral Mucosa
I. Muco-cutaneous Junction.

11. Junctions in Oral Mucosa
I. Muco-cutaneous
II. Muco-gingival
III. Dento-gingival

12. Junctions in Oral Mucosa
II. Muco-gingival Junction.

13. Junctions in Oral Mucosa
II. Muco-gingival Junction.
 Thick nonk. St. sq.
epith.
 Lamina propria
with elastic fibers.
 Parak. St. sq.
epith.
 Lamina propria
with course
collagen fibers.

14. Junctions in Oral Mucosa
I. Muco-cutaneous
II. Muco-gingival
III. Dento-gingival

15. Junctions in Oral Mucosa
III. Dento-gingival Junction.
 Collar around the tooth.
 Thick at the coronal
end…. Bottom of the
gingival sulcus.
 Tapers apically… at the
enamel surface.

16. Junctions in Oral Mucosa
III. Dento-gingival Junction… Histology
 Epithelium..
 Nonk. St. sq. epith.
 Basal cell layer
I. Cuboidal cells
II. Attachment.. desmosomes &
hemi-desmosomes.
 Supra-basal and superficial cells
a) Polyhedral then spindle or
flattened.
b) 3-4 layers apically to 15-30
layers coronaly.
c) Prominent intercellular spaces.
d) Obliquely directed to reach
tooth surface parallel to it.

17.  Basal lamina..
 External basal lamina
i. Lamina lucida.
ii. Lamina densa.
 Internal basal lmaina
i. Lamina lucida .
ii. Lamina densa.
 Epithelial attachment..
 Submicroscopic, 40 nm extracellular
amorphous substance.
 Formed and maintained by the superficial
layer of the attachment epith.
 Formed of…
i. Lamina lucida .
ii. Lamina densa.
Junctions in Oral Mucosa
III. Dento-gingival Junction… Histology

18.  Cells of junctional epith. differ in
I. High rate of cell division.
II. High rate of turnover.
III. Large amount of cytoplasm, rER and golgi.
IV. Less tonofilaments and desmosomes.
V. Larger inter-cellular spaces contain lymphocytes,
plasme cells and macrophages.
Junctions in Oral Mucosa
III. Dento-gingival Junction… Histology

19.  Lamina propria..
 Less collagen fibers
 Contains inflammatory cells.
 Integrity of the dento-gingival
junction.
Junctions in Oral Mucosa
III. Dento-gingival Junction… Histology

20. Junctions in Oral Mucosa
III. Dento-gingival Junction.
Let’s remember

21. Junctions in Oral Mucosa
III. Dento-gingival Junction… Development

22. Junctions in Oral Mucosa
III. Dento-gingival Junction… Gingival Sulcus
 Capillary cleft found between the inner
surface of the free gingival and the
tooth surface.
 Lined by nonk. epith.
 Its depth varies from 0-6 mm and the
average depth 1-8 mm.
 The more shallow the sulcus the more
favorable the condition of the gingival
margin.

23. Junctions in Oral Mucosa
III. Dento-gingival Junction… Migration
• Active eruption.. The tooth
actually moves from its crypt to
the oral cavity ; about 13- 14
of the crown is still covered by
the gingival.
• Passive eruption.. Gradual
exposure of the remaining
portion of the crown and may
even cementum.

24. Junctions in Oral Mucosa
III. Dento-gingival Junction… Migration
 The bottom of the gingival sulcus is located on
enamel.
 Apical end of attachment epithelium stays on
the CEJ.
 In primary dentition almost up to one year of
age before shedding.
 In permanent dentition up to one year of age
before shedding, and in permanent dentition
usually to the age of 20 or 30 years.
 Anatomical crown is larger than the clinical
crown.

25. Junctions in Oral Mucosa
III. Dento-gingival Junction… Migration
 The bottom of the gingival sulcus is still on enamel.
 The apical end of the attachment epithelium has shifted to
cementum surface.
 Till the age of 40 years of age or may even later.
 The anatomical crown is still larger than the clinical crown.

26. Junctions in Oral Mucosa
III. Dento-gingival Junction… Migration
 The bottom of the gingival sulcus is at the CEJ.
 Epithelial attachment is entirely on cementum.
 The anatomical crown is equal to the clinical
crown.

27. Junctions in Oral Mucosa
III. Dento-gingival Junction… Migration
 The entire attachment epithelium and the
gingival sulcus lie in cementum.
 The age at which this stage is variable.
 The gingival recession is related to the
advancement of the previous stage.
 The anatomical crown is less than clinical
crown.

28. Junctions in Oral Mucosa
III. Dento-gingival Junction… Migration

29. Any questions??

30. Thank you..