The oral mucosa of the edentulous ridges presents many morphological macroscopic and microscopic variations, from one area of the edentulous ridge to another, as well as from one patient to another. Because the mobile prosthetic treatment realizes a direct contact between the dental prosthesis and the mucosa of the denture supporting structures and of the peripheral structures, the prosthetic success depends on establishing a correct and long lasting relation between them. The present article's purpose is to present the pro-prosthetic and prosthetic treatment possibilities for partial or complete edentulous patients who have variations of the mucosa of the residual ridges, as well as to present the histopathological importance of these variations. The mucosal characteristics essentially influence the attitude in the different treatment phases of a mobile dental prosthesis, the prosthetic success depending on the establishment of a correct and long lasting relation between the dental prosthesis and the oral mucosa.