The skin is the body's first line of defense against the environment, particularly against pathogens, chemicals, and allergens. It is now known that a class of biological molecules called acylceramides and their metabolites, protein-bound ceramides, are essential to the formation of this barrier. The outermost tissues of the mouth are closely related to the skin and have similar functions—to create an oral barrier. However, little is known about the role and importance of acylceramides and protein-bound ceramides in the oral barrier.
