The aim of this study was to evaluate the change in occlusal force at denture dislodgement (OFD) in patients with poorly fitting complete dentures after improvement. In 91 patients, OFD was recorded before treatment, immediately after fitting the renewed denture (direct effect), and 1 week, 1 month, and 6 months later (adaptation). OFD increased significantly (P .01) after optimizing the dentures and was dependent on patients' gender and age. The greatest changes occurred within the first week. It can be concluded that the increase in OFD is not only induced by the optimized denture, but also - and to an even greater extent - by adaptation.