Recently, flexible denture is widely used with some advantages such as esthetics, flexibility and biocompatibility. However, there is an opposite opinion about stability because of the movement of denture by the material's flexibility. As the denture moves to tissue surface during mastication, it irritates the supporting tissue. It can lead to trauma and rapid resorption of residual ridges if this irritation lasts for a long time. In this case, the patient has used flexible denture with insufficient stability, retention and support for several years and thus continuous irritation of the supporting tissue resulted in palate bone exposure. The patient discomfort and palate bone exposure underwent improvements by the new denture with stability and retention. A careful case selection for flexible denture, regular checkup and proper treatment are necessary to prevent the side effects.