Influence of the dimensions of implant superstructure on peri-implant bone loss.

Two groups totaling 81 patients were selected. One group of edentulous patients had two IMZ implants, a bar, and an overdenture placed. The second group received a fixed restoration supported by one IMZ implant and one natural tooth. A superstructure constant was defined and used to combine the length and height of the Dolder bar or fixed prosthesis. Radiological bone loss was compared to the dimensions of the superstructure. The results showed a clear optimum for the dimensions of the superstructure on implants for the edentulous patient. Two implants connected with an overdenture should be placed 22 to 27 mm (between the centers of the implants) apart for best results. For fixed partial dentures no optimum dimensions could be found.