Twenty-three edentulous patients who had been treated with a mandibular fixed complete denture retained by osseointegrated implants were followed over a 10-year period. Nine of these patients had received a maxillary fixed implant-supported complete denture prosthesis after the initial placement of the mandibular restoration, while the remainder still used a conventional maxillary complete denture. The maximal occlusal force or mastication efficiency index of those having fixed implant-supported prostheses in both arches did not differ markedly from those having only a mandibular restoration. However, at the 3-year examination, lower values were recorded for the self-rated masticatory ability, while higher values were given after 10 years. It was concluded that placement of a mandibular fixed implant-supported prosthesis in dissatisfied complete denture wearers led to a dramatic improvement of masticatory function that was quite acceptable for many patients. However, some patients subsequently demanded a maxillary fixed prosthesis to feel satisfactorily rehabilitated.