OBJECTIVE The objective of this study was to compare denture satisfaction and chewing ability of edentulous patients treated with dental implant-retained overdentures or with full dentures with or without previous preprosthetic surgery. METHODS This study was a controlled clinical trial. Thirty-eight men and 52 women participated in the study. The mean height of the anterior mandible was 21 mm (range, 16 to 25 mm), measured on a lateral cephalometric radiograph. The subjects were randomly assigned to the three treatment modalities. The main outcome measures were denture satisfaction and chewing ability, which were assessed using questionnaires focusing on denture-related complaints and the ability to chew different types of food, and an overall denture satisfaction score. RESULTS Based on the baseline data from the "denture complaints" and "chewing ability" questionnaires, nine interpretable factors could be extracted. Two factors did not vary following treatment and were excluded from the outcome analysis. At the 1-year evaluation five of seven factors showed significantly better scores for the two surgical groups than for the control group. The same was found for the overall denture satisfaction rate. CONCLUSIONS Overdentures retained by dental implants or complete dentures made after a vestibuloplasty and deepening of the floor of the mouth provide a more satisfactory solution for denture-related problems than complete dentures alone. For the scale "functional complaints lower denture," the overdenture group showed even a significantly better score than the preprosthetic surgery group.