The influence of a complete lower denture destabilization on the pressure of the mucous membrane foundation

The results of previous studies on the pressures beneath the mucous membrane-supported dentures are contrary to the prevailing pain sensations and discomfort reported in practice. In this work, a FEM analysis of large displacements was used for calculation of the contact stresses beneath a lower denture that accompany destabilization under the realistic oblique mastication forces and stabilization of a non-working flange at the balancing contacts. The pressure on the surface of a mucous membrane beneath a denture that was loaded in a stable manner with a vertical occlusal force of 100 N was lower than the pain threshold. It was even more surprising as the extremely unfavorable lower denture foundation conditions were selected for this analysis. The lateral mastication forces destabilized the denture by means of tilting it and reducing its supporting area. Significant pressures calculated for the destabilization are consistent with the clinically observed decrease or a complete lack of chewing efficiency in the cases of unfavorable foundation conditions. A fundamental importance of the balancing contacts for the chewing efficiency was confirmed quantitatively. A remarkable development which has been achieved in the modeling of the denture functioning conditions is crucial for further biomechanical investigations of the mucous membrane-supported dentures, as well as for the implant-retained dentures.