1. Junctional Epithelium / Epithelial Attachment
What and where it is
Where it comes from
What it does
Why it does it

2. What and Where is the Junctional Epithelium
Epithelial attachment and clinical attachment level
Collar-like band of nonkeratinised stratified squamous epithelium
Extends from cementoenamel junction - bottom of gingival sulcus
Coronally: cells thick. Apically: narrows to 1-3 cells
Length: 0.25 – 1.35mm & has rate of turnover

3. A- gingiva
B- sulcular epithelium
C- junctional epithelium
D- lamina propria (connective tissue)
E- alveolar process
F- PDL
ES- enamel space
JE – junctional epithelium
CT- connective tissue

4. Where does it come from ?
Initially derived from Reduced Enamel Epithelium
REE replaced once tooth erupts – REE covering crown lost rapidly replaced by squamous epithelial cells
Transformed REE & oral epithelium form dentogingival junction and junctional epithelium
Final conversion of REE to JE may not occur until 3-4 years post eruption

5. Important Features
Cells of JE immediately adjacent to tooth attach to tooth by hemidesmosomes & basal lamina
Combination is known as the epithelial attachment
Basal lamina in contact with tooth: Internal Basal lamina
On opposite surface – JE in contact with lamina propria of gingiva & attached by hemidesmosomes and basal lamina
Basal lamina in contact with lamina propria: External Basal Lamina

6. Junctional epithelium is unique as it possess 2 basement membranes – the internal and external basal lamina
Enamel
Lamina propria
Hemidesmosomes
Internal Basal Lamina
External Basal Lamina

7. JE CT
External basal lamina
Enamel space
Internal basal lamina

8. Enamel Cuticle Not visible in demineralised sections
Non-mineralised structure between JE and underlying hard tissue
Cuticle also seen between JE and underlying cementum

9. Length of Junctional Epithelium
Length varies according to stage of eruption
Tooth first erupts – most of enamel covered by JE
Tooth reaches occlusal plane – ¼ enamel surface covered
Eventually JE lies close to CE junction
Older patients with root exposure (passive eruption or disease) JE proliferates apically - firm attachment with cementum

10. Other Fantastic Facts You Really Wanted to Know About the Junctional Epithelium!!!!
Lamina propria of gingiva – good vaculature and source of nutrient to JE and source of GCF
JE is permeable & tissue fluid and cells pass into GCF
Turnover of JE is rapid. Epithelial cells migrate coronally & shed into oral cavity via gingival crevice
Rate of turnover dependent on demands placed on tissue. Directly related to degree of inflammation

11. What it does and why it does it
Has attachment role and protective role
Permeability allows GCF and defence cells to pass across to protect underlying tissues from disease processes (periodonal disease)
Helps maintain integrity of tooth / periodontium structure.

12. Role of JE – Clincial significance
GCF contains g globulins and ploymorphonucleocytes (PNMs) giving it immunological / phagocytic properties to combat disease processes
Such molecules pass readily across JE to underlying tissues
JE (& GCF) good indicator for severity of periodontal disease – may contain neutrophils & other inflammatory cells indicating disease – & state of health of periodontium
Research into this ongoing in Bham – understanding progression of disease & development of diagnostic marker of severity of disease

14. Reason why I have not been around for the past 2 weeks!!