Seventy two partial subperiosteal implants were inserted in 52 patients. Thirty six of these implants had a classical design in which the submerged structure had thick primary and secondary connectors. Thirty six implants had a newly designed submerged structure consisting of long and thin primary connectors with grooves along their outer surfaces designed to stop or delay the downgrowth of epithelial mucosa. A six year evaluation revealed a 92.5% success of the newly designed implants and an 84% success for the classical design. A 10 year statistical projection revealed a 50% cumulative success for the classical design and a 92.5% success for the new design.