Zambelis, George (Department of Periodontics, School of Dentistry, Athens University)
It has been well documented that a few remaining teeth with healthy but reduced periodontal support (25-30%) may serve as abutments for fixed bridges. In case of unfavorably distributed remaining teeth, the installation of a number of screw shaped implants may increase the bone supported area of a fixed bridge, through a rigid connection between natural teeth and osseointegrated implant.
The goal of the clinical project is to evaluate a method to determine the necessary number of implants needed to restore such dentitions.
A number of seventy one (7l) patients, 33 males and 38 females (mean age, 56 years) received one hundred forty three (143) osseointegrated implants, of different length. Patient selection criteria were set, and initial calculation of the periodontal ligament area of remaining teeth was established. Additionally, the rnaximal periodontal ligament area of teeth to be replaced, and bone supported area needed, was evaluated by the calculation of the surface area of implants necessary for installation. A total number of fifty seven (57) unilaterally and fourteen (14) of horse shoe shaped fixed bridges were used. A number of eighty (80) implants served as end abutments, mesialy or distally and sixty three (63) as intermediate abutments. Fifty four (54) of implant end abutments provided support to one or two cantilevers. A total number of sixty nine (69) cantilevers were used to extend the occlusal surface of the bridge. Bone high around implants calculated at the time of fixation. A five year post treatment program established and bone high calculated through a panoramic extra oral radiographic evaluation, once a year. During this period none of the implants lost and bone high remained stable. No symptoms (pain, etc.) were detected.
It is concluded that this method may be a solution to the problem concerning the number of implants needed to restore dentitions compromised by periodontal disease.