The document discusses the junctional epithelium, which forms a collar-like attachment of stratified squamous epithelium connecting the tooth and gingiva. It describes the junctional epithelium's structure, development, functions in protecting the periodontium, and role in gingivitis and pocket formation. The document also reviews regeneration of the junctional epithelium, effects of trauma and implants, and syndromes that can affect it.

1. Dr. BEENA VIJAYAN PARVATHY
1st YEAR POST GRADUATE
Dept of Periodontics and Implantology
JUNCTIONAL EPITHELIUM

2. CONTENTS
• Definitions
• History
• Development of junctional epithelium
• Structure
• Dynamic aspects of junctional epithelium
• Expression of various molecules and their functions
• Permeability
• Functions
• Role of JE in gingivitis
• Role of JE in initiation of pocket formation
• Passive Eruption
• Effect of Trauma from Occlusion on JE
• Junctional Epithelium Adjacent to Oral Implants
• Syndromes Affecting JE
• Regeneration of junctional epithelium
• Conclusion
• References

3. INTRODUCTION
Junctional epithelium is the non-keratinizing stratified squamous epithelium, that
surrounds the tooth like a collar with a cross- section resembling a thin wedge.
• Epithelium of the gingiva which gets attached to the tooth is junctional or
attachment epithelium.
• Derived from the reduced enamel epithelium (REE) during tooth development.
• Forms the floor of sulcus and attaches gingiva to tooth surface.
• The union between this epithelium and tooth is referred to as epithelial attachment.
• Resembles REE in its structure in that they have a basal layer and few layers of
flattened cells

4. DEFINITIONS
The junctional epithelium consists of a collar like band of stratified squamous non-
keratinizing epithelium. (Joseph P, 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. (Glossary of Periodontal Terms)
The innermost cells of the junctional epithelium form and maintain a tight seal against
the mineralized tooth surface. (Schroeder and Listgarten, 1977)

5. TERMINOLOGIES
Epithelial attachment – Gottlieb 1921
Epithelial cuff - Waerhaug 1952
Attached epithelial cuff - Orban 1956
Attachment epithelium - Grant, Stern 1968
Junctional epithelium - Anderson and Stern1967

6. HISTORY
The first to describe the junctional epithelium.

7. Based on his animal experiments(in dogs).

10. DEVELOPMENT OF JE

11. STRUCTURE
• Anatomical aspects
• Junctional epithelium and interstitial cells
• Epithelial attachment

12. Anatomical aspects
Part of marginal free gingiva
• Forms a collar
• Interproximal area, fuse to form epithelial lining of interdental col
• Coronal termination – free surface: -Pristine conditions: CEJ to gingival margin
(~2 mm height) (Gargiulo et al,1961).
-Normal gingiva: subclinical inflammation bottom of gingival sulcus (Brecx et al,1987)
• Apically & laterally – bordered by soft connective tissue – smooth surface; mild
undulation coronally.
• Coronal-most – sulcular epithelium
• Apical termination – Epithelium in continuity with network of epithelial cell rests of
Malassez. (Spouge,1984)

13. JE is a collar-like band of nonkeratinised stratified squamous epithelium extending from
cemento-enamel junction to bottom of gingival sulcus.
• Coronally it is 15-30 cells thick and apically narrows to 1-3 cells
• Its length varies from 0.25 – 1.35mm.
• Made up of 2 layers, stratum basale ( towards CT) and stratum suprabasale (facing
tooth surface).
• Organelles- lysosomal bodies, golgi fields, polyribosomes, cisternae of RER are
abundant.
• All JE cells express unique set of cytokeratins 5, 13, 14, 19 & occasionally 8, 16, 18.
• Cells are connected by Desmosomes.
• Fluid filled intercellular spaces may vary in width.
Junctional epithelium and interstitial cells

14. Epithelial Attachment Apparatus
The term epithelial attachment: refers to the attachment apparatus, i.e. internal basal
lamina & hemidesmosomes that connects the junctional epithelium to the tooth surface.
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.
1. LAMINA LUCIDA or lamina rara
2. LAMINA DENSA
3. LAMINA FIBRORETICULARIS (sub-basal lamina)

15. Dynamic Aspects Of Junctional Epithelium
DAT Cells (Directly Attached to Tooth cells)
• The turnover of the junctional epithelium is exceptionally rapid.
• At the coronal part of the JE, the DAT cells typically express a high density of
transferrin receptors.
• Any structural or molecular changes in the internal basal lamina can potentially
influence the vital functions of the DAT cells and contribute to the effectiveness or
failure of the junctional epithelial defense or vice versa.
• Changes in the cell metabolism may affect the Internal Basal Lamina (IBL).
– migrate towards the sulcus bottom
– Connected via hemidesmosomes to basal lamina → not static but dynamic

16. Expression Of Various Molecules And Their
Functions

17. PERMEABILITY
The junctional epithelium is the most permeable portion of the gingival epithelia.
Because of its permeability to bacterial products and other assorted antigens, the
connective tissue adjacent to the junctional epithelium tends to become infiltrated with
chronic inflammatory cells, primarily lymphocytes and plasma cells.

18. FUNCTIONS
Has attachment role and protective role.
• Permeability allows GCF and defence cells to pass across to protect underlying tissues
from disease processes (periodontal disease).
• Helps maintain integrity of tooth/periodontium structure.
• GCF contains γ globulins and poly-morphonuclear leukocytes (PMNs) giving it
immunological/phagocytic properties to combat disease processes.
• Such molecules pass readily across JE to underlying tissues.
• JE may contain neutrophils & other inflammatory cells indicating disease & state of
health of periodontium.
• The junctional epithelium plays a crucial role since it essentially seals off periodontal
tissues from the oral environment.
• Its integrity is thus essential for maintaining a healthy periodontium.

19. ROLE OF JE IN GINGIVITIS

20. Role Of JE In Initiation Of Pocket Formation

21. ROLE IN Passive Eruption

22. Effect of Trauma from Occlusion on JE
TFO causes widening of the marginal PDL space, a narrowing of the
interproximal alveolar bone.
In case of TFO, the junctional epithelium will be intact and there will be
no degeneration of the epithelial tissues unless there is any plaque
accumulation.

23. Junctional EpitheliumAdjacent to Oral Implants
Junctional epithelium around implants always originates from epithelial cells of oral
mucosa.
Despite different origins of the 2 epithelia, a functional adaptation occurs when oral
epithelia form an epithelial attachment around implants.
Evidence of several of the mentioned marker molecules involved in the defense
mechanisms against the bacterial also being expressed in the peri-implant epithelium.

25. Syndromes Affecting JE
Kindler syndrome:
A rare skin blistering disorder along with early onset aggressive periodontitis.
Due to loss of kindlin-1 protein which is involved in integrin activation.
JE fails to attach to the tooth surface.
(Yildirim et al,2017)
Haim-Munk syndrome and Papillon-Lefèvre syndrome :
Due to allelic mutations in cathepsin C.
JE gives rise to episodic inflammation and destruction of gingiva.
(Hartal,2000)

26. REGENERATIONOF JUNCTIONAL EPITHELIUM
A new junctional epithelium after gingivectomy may form within 20 days.
(Listgarten, Schroeder, 1977)
A new and complete attachment indistinguishable from that in control was established
5 days after complete separation of the JE from the tooth surface.
(Taylor and Campbell, 1972)
The reestablishment of the epithelial seal around implant after probing around implant
is around 5 days.
(Etter et al., 2002)
Detachment of cells persistes for 24 hrs and new attachment of junctional epithelial cell
started 3 days after flossing ceased.
(Waerhug, 1981)

27. These studies show that the junctional epithelium is a highly dynamic and adaptive
tissue with a fast capacity for self-renewal or de novo formation from basal cells of the
oral gingival epithelium.

28. CONCLUSION
The junctional epithelium is a unique tissue that fulfills a challenging function at the
border between the oral cavity, colonized by bacteria, and the tooth attachment
apparatus.
It represent key mechanism in host parasite interraction, since it actively participates in
the host defense mechanism rather than simply providing an attachment to the tooth
surface.
These defense mechanisms may be overwhelmed by bacterial virulence factors, and the
gingival lesion could progress to periodontitis.

29. REFERENCES
• Carranza’s-Clinical Periodontology, 11th 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.