This clinical study evaluated the use of a spark erosion overdenture where the bar extended to implants in the maxillary tuberosities. Six IMZ implants were placed bilaterally and symmetrically in the incisor, canine, and tuberosity regions of the edentulous maxillae of 11 patients. A full-arch milted precision bar was made with a cobalt chromium alloy. Some bars also had an attachment placed in the midline to compensate for divergent abutments. An overdenture with a superstructure made using the spark erosion process was fabricated for each patient Five percent of the fixtures were lost prior to prosthetic treatment. An additional evaluation was made using strain gauges to assess stresses in the implant bar. The bar supported by six implant abutments produced evenly distributed stress. When the intramobile elements and transmucosal implant extensions were removed from the distal abutments simulating a cantilever situation, there was a less favorable distribution of stress. The authors listed the following advantages of the spark' erosion overdenture combined with an implant bar with support from the tuberosity region: even load distribution, lack of palatal coverage, compensation for divergent fixtures and anatomical defects, and elimination of phonetic problems.