However, while evidence has previously been demonstrated regarding high serum ET-1 levels as primary mediators of endothelial dysfunction or in the development of cardiovascular risk, from the author’s knowledge, there is no specific evidence to determine ET-1 levels in saliva in order to evaluate whether the increased expression of salivary ET-1 levels determines, by reflection, an increase in ET-1 in serum and then analyzes the salivary levels of ET-1 as an index of endothelial dysfunction. This evidence concerns the gene EDN1 and endothelial dysfunction.