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1. JUNCTIONAL
EPITHELIUM
Priyanka Doshi
1st year PG

2. Table of Contents
• Introduction.
• Development of Junctional Epithelium.
• Concepts of Epithelial Attachment.
• Passive Eruption.
• Anatomical Aspect.
• Functions of Junctional Epithelium.
• Junctional Epithelium Adjacent to Oral Implants.
• Regeneration of Junctional Epithelium.
• Conclusion.

3. Introduction
• Definition
• The junctional epithelium consists of a collar like band of stratified
squamous non-keratinizing epithelium.
Joseph P. Fiorellini (carranza’s 10th Edition)
• A single or multiple layer of non-keratinizing cells adhering to the tooth surface at
the base of the gingival crevice. Formerly called epithelial attachment.
[Glossary of periodontal terms]
• The innermost cells of the junctional epithelium form and maintain a tight seal
against the mineralized tooth surface, the so-called epithelial attachment
(Schroeder and Listgarten,1977)

4. • Three types of mucous membrane lined oral cavity i.e.
masticatory mucosa, lining mucosa, spacialized mucosa.
• Gingiva is a part of masticatory mucosa which consist of three
types of epithelium i.e. oral epithelium, sulcular epithelium and
junction epithelium.

5. • Je is a non keratinized
squamous epithelium.
• composed of two
strata:
• the basal layer facing the
connective tissue
• suprabasal layer
extending to the tooth
surface.

6. Development
RE-Reduced Dental/Enamel Epithelium EAL-Epithelial Attachment Level
OE-Oral Epithelium AB-Ameloblast

7. Passive Eruption
First Stage Second Stage Third Stage Forth Stage
According to the concept of continuous eruption ( GOTTLIEB & ORBAN 1933)
PASSIVE ERUPTION : the exposure of teeth by apical migration of gingiva

8. History
• Gottlieb (1921) was the first to describe the junctional
epithelium.
• Schroeder and Listgarten (1977) clarified the anatomy and
histology of the dentogingival junction in their monograph:
‘Fine structure of developing epithelial attachment of human
teeth’.

9. HISTORICALCONCEPTS OF
ATTACHMENT
• Gottlieb’s concept (1921) :
• Soft tissue of gingiva is organically united to enamel surface.
• He termed the epithelium contacting the tooth “epithelial attachment”.
• Orban’s concept (1953)
• He stated that the separation of the epithelial attachment cells from the
tooth surface involved preparatory degenerative changes in the
epithelium.

10. • Waerhaug’s concept (1960)
• He presented the concept of epithelial cuff. This concept was based on
insertion of thin blades between the surface of tooth and the gingiva
• Blades could be easily passed apically to the connective tissue
attachment at CEJ without resistance.
• It was concluded that gingival tissue and tooth are closely adapted but
not organically united.

11. • Schroeder and Listgarten concept (1971)
• Primary epithelial attachment refers to the epithelial attachment
lamina released by the REE. It lies in direct contact with enamel
and epithelial cells attached to it by hemi-desmosomes.
• When REE cells transform into JE cells the primary epithelial
attachment becomes secondary epithelial attachment .

12. Characteristics of Junctional Epithelium
collar-like band of stratified squamous nonkeratinizing epithelium.
length of junctional epithelium ranges from 0.25 to 1.35mm.
tapers from its coronal end(10 to 20) to apical end (1 to 2)
Cells leave the external basal lamina and migrate to the free surface
of the junctional epithelium located at the base of the gingival sulcus,
where they are exfoliated.

13.  The stability of connective tissue attachment is a key factor in
limiting the migration of the junctional epithelium.
 rate of cell turnover in the junctional epithelium: 4–6 days.
Keratins present are k5, k13, k14, k19
It has reduced glycolytic enzyme activity and lacks acid
phosphatase
The cells are arranged into basal & suprabasal layers & do not
exhibit granular or cornified layers
3 zones in junctional epithelium are apical, coronal & middle

14. Epithelial attachment apparatus
• The attachment of the junctional epithelium to the tooth is mediated
through an ultramicroscopic mechanism defined as the epithelial
attachment apparatus.
• It consists of hemidesmosomes at the plasma membrane of the
cells directly attached to the tooth (DAT cells) and a basal lamina-
like extracellular matrix, termed the internal basal lamina, on the
tooth surface.

15. • HD =
Hemidesmosomes
• E= Enamel
• AF = Anchoring Fibers
• LD= Lamina densa
• LL= Lamina lucida

16. Epithelial attachment at molecular level
• Basement membrane – specialized extracellular
matrices
• Functions-
a. Filtration (selective permeability barrier function)
b. Cell polarization, migration.
c. Cell adhesions
d. Cell differentiation.

17. • INTERNAL BASAL
LAMINA
•It consists of two
layers: the lamina lucida
and lamina densa.
•Hemidesmosomes (HD)
originate from the
lamina lucida, and
tonofilaments splay out
from each
hemidesmosome.

18. • The internal basement membrane was initially described as an 80-
120nm wide homogeneous layer.
• It directly faces the enamel, with an intervening laminated or non-
laminated layer of cuticles (Listgarten, 1966) or afibrillar cementum
(Kobayashi et al., 1976).
• In the cytoplasm of the cells of the junctional epithelium, the
tonofibrils are associated with hemidesmosomes.
• The internal basement membrane of the dentogingival border is
uniquely specialized for mechanical strength, sealing off the
periodontal tissues from the oral environment (Sawada & Inoue,
1996).

19. • The lamina densa of the internal basement membrane is
closely associated with an additional layer referred to as the
supplementary lamina densa found on the enamel side of the
tooth.
• One part of the basement membrane, the supplementary
lamina densa, is mineralized.
• This mineral deposit is continuous with that of the enamel of
the tooth, and thus this deposit on the supplementary lamina
densa forms an advancing edge of mineralization.
(Sawada & Inoue, 2003)

20. • In the mineralized portion of the lamina densa, mineral
crystals were arranged in a network pattern
• This may facilitate more powerful gripping, and further
demonstrates the elaborate mechanism by which firm
binding of the mineral and organic phases is achieved.

21. Function
• Junctional epithelium is firmly attached to the tooth and
thus forms an epithelial barrier against the plaque bacteria.
• It allows the access of GCF, inflammatory cells and
components of the immunological host defense to the
gingival margin.
• junctional epithelial cells exhibit rapid turnover, which
contributes to rapid repair of damaged tissue

22. EXPRESSION OF VARIOUS
MOLECULES
• JE cells have surface or cell membrane molecules that play a role in
cell matrix and cell-cell interactions.
• JE cells express numerous cell adhesion molecules (CAM’s), such
as integrins and cadherins.
• Integrins – are cell surface receptors that mediate interactions
between cell and extracellular matrix, and also contribute to cell to
cell adhesion..

23. • The cadherins are responsible for tight contacts between cells.
• E-cadherin, an epithelium specific cell adhesion molecule,plays crucial role
in maintaining the structural integrity
•CEACAM-1 is a transmembrane cell adhesion molecules which participate in
regulation of cell proliferation, stimulation and co-regulation of activated t-
cell.
•ICAM-1 and LFA-3 guiding PMNs towards the bottom of the sulcus.
• high expression of interleukin-8 (IL-8), a chemotactic cytokine, is seen in the
coronal-most cells of the junctional epithelium

24. • IL-1 α , IL-1β and TNF –α are strongly expressed in coronal half
of the junctional epithelium and play a role in the defence against
the bacteerial challenge in the gingival sulcus.
•EGF – involved in epidermal growth, differentiation and wound
healing.
• natural antimicrbial molecules : α and β defensins
LL37
calprotectin

28. Turnover rate of Junction epithelium
• The turnover rate of JE cells is exceptionally rapid.
• The DAT cells express a high density of transferrin receptors supporting
the idea of active metabolism and high turnover.
• DAT cells have an important role in tissue dynamics and reparative
capacity of the JE.
• The existence of a dividing population of DAT cells in a suprabasal
location in several layers from connective tissue is a unique feature of JE.

29. Mechanism of cells turnover
(1)The daughter cells are produced by dividing DAT
cells and replace degenerating cells on the tooth
surface.
(2) The daughter cells enter the exfoliation pathway
and gradually migrate coronally between the basal
cells and the DAT cells to eventually break off
into the sulcus, or
(3)Epithelial cells move/migrate in the coronal
direction along the tooth surface and are replaced
by basal cells migrating round the apical
termination of the junctional epithelium.

30. REGENERATION OF THE JUNCTIONAL
EPITHELIUM
• Injury to JE may occur due to intentional or accidental trauma.
• Accidental trauma can occur during probing, flossing or tooth margin
preparations for restorations.
• Intentional trauma occurs during periodontal surgeries where the JE is
completely lost.
• Many studies have been done to investigate the renewal of JE. These include
studies done on renewal of JE on tooth and implant surface after mechanical
detachment by probing.
• Studies have been done on mechanical trauma during flossing and on regeneration
of JE after gingivectomy procedure which completely removes JE.
(Waerhug 1981, Shchorder and listgarten 1977)

31. • Taylor and Campbell 1972: A new and complete attachment
indistinguishable from that in control was established 5
days after complete separation of the JE from the tooth
surface.
• Etter et al. 2002 : the reestablishment of the epithelial seal
around implant after probing around implant is around 5
days.

32. • Waerhug 1981 : detachment of cells persistes for 24 hrs and
new attachment of junctional epithelial cell started 3 days
after flossing ceased.
• Shchorder and listgarten 1977 : a new junctional epithelium
after gingivectomy form within 20 days.

33. Junctional epithelium in periodontitis
• Schluger et al 1977: Pocket formation is attributed to a loss of
cellular continuity in the coronal most portion of the JE
• Thus the initiation of pocket formation may be attributed to the
detachment of the DAT cells from the tooth surface or to the
development of intraepithelial split.
• Takata and Donath (1988) observed degenerative changes in
the second or third layer of the DAT cells in the coronal most
portion of the JE cells facing the biofilm.

34. • Schroeder and Listgarten 1977: An
increased number of mononuclear
leukocytes (T and B cells, macrophages)
together with PMNs are considered as
factors contributing to the disintegration
of the JE.
• The degeneration and detachment of DAT
cells exposes tooth surface and creates a
sub-gingival niche suitable for the
colonization of anaerobic gram-negative
bacteria and apical growth of dental
plaque.

35. Junctional epithelium in the antimicrobial
defense
•The external basement membrane
forms an effective barrier against
invading microbes
•Active antimicrobial substances are
produced in junctional epithelial cells:
defensins and lysosomal enzymes.

36. JUNCTIONAL EPITHELIUMAROUND IMPLANT
• The junctional epithelium around implants always originates
from epithelial cells of the oral mucosa, as opposed to the
junctional epithelium around teeth which originates from the
reduced enamel epithelium.
• Despite different origins of the 2 epithelia, a functional
adaptation occurs when oral epithelia form an epithelial
attachment around implants.

37. NATURAL TOOTH IMPLANT
Epithelium tapers
towards the depth •Epithelium is thicker
Large number of cell
organelles
Few organelles
Fibers are arranged
perpendicular
Fibers are arranged
parallely
Numerous kerato-
hyalin granules

38. Conclusion
• The junctional epithelium is a unique tissue that fulfills a
challenging function at the border between the oral cavity.
• It represent key mechanism in host perasite interraction,
since it actively participates in the host defense
mechanism rather than simply providing an attachment to
the tooth surface.

39. References
• Carranza’s-Clinical Periodontology, 10th Edition
• Lindhe-Clinical Periodontology and Implant Dentistry, 5th
Edition.
• Periodontology 2000, Volume 3, 1993-Tissues and Cells of the
periodontium.
• Periodontology 2000, Volume 13, 1997-Molecular and cell
biology of the gingiva.
• Periodontology 2000, Volume 24, 2000-Structure and function
of the tooth-epithelial interface in the health and disease.
• D. D. Bosshardt and N. P. Lang Review on the Junctional
Epithelium: from Health to Disease. Journal of Dental Research
2005.
• Masaki Shimono et al., Review, Biological Characteristics of
the junctional epithelium. Journal of Electron Microscopy 2003

40. THANK YOU