In a healthy-case scenario, the probe is gently inserted, slides by the sulcular epithelium (SE), and is stopped by the epithelial attachment (EA).
As the tooth actively erupts, the coronal part of the fused and surrounding epithelium peels back off the crown.
[3] Cells in the junctional epithelium tend to have wide intercellular spaces and fewer desmosomal junctions, to allow the transmission of white blood cells (WBCs) from lamina propria's blood vessels to the bottom of the gingival sulcus, to help prevent disease.
These superficial, or suprabasal, epithelial cells of the JE provide the hemidesmosomes and an internal basal lamina that create the EA, because this is a cell-to-noncellular type of intercellular junction.
The EA is very strong in a healthy state, acting as a type of seal between the soft gingival tissue and the hard tooth surface.
[6] The JE cells have many organelles in their cytoplasm, such as rough endoplasmic reticulum, Golgi complex, and mitochondria, indicating a high metabolic activity.
[3] The increased permeability of the JE that allows emigration of the PMN type of WBC also allows microorganisms from the dental biofilm (especially noted is P. gingivalis, and associated toxins from the exposed tooth surface) to enter this tissue from the deeper lamina propria, setting up the possibility of infection to occur.
[8][9] In addition, there is the presence of ulceration with gingival hyperplasia, including the formation of rete ridges and connective tissue papillae at the one smooth interface of the JE with the lamina propria.