Role of junctional epithelium in maintaining dento-gingival adhesion and periodontal health.

The dento-gingival junction comprises multiple epithelia including the junctional epithelium (JE), which is the most coronally-located structural element of the dento-gingival junction that demarcates external from internal periodontal environments. After tooth eruption into the oral cavity, a specialized basal lamina is formed that provides a firm attachment of the JE to the enamel. This attachment prevents microbial species and oral debris from entering subjacent periodontal tissues. Here we discuss the expression of certain JE adhesion molecules and enamel proteins that maintain the health of the dento-gingival junction but that are perturbed in the pathogenesis of periodontitis. We also consider how evolutionary processes have influenced the development of the JE as a specialized adhesion that is well-suited for protection of the dento-gingival junction. A detailed understanding of the biology of the JE will deepen current models of dento-gingival adhesion, potentially clarify inter-patient variability of susceptibility to periodontitis and help to identify new roles of enamel proteins in periodontal regeneration.