即時荷重インプラントに関する臨床的検討： ３年経過時の臨床成績

抄録

The purpose of this study was to determine whether clinical success can be achieved with immediate loading in the edentulous maxilla and mandible with Brånemark implants (Nobel Biocare, Gotebörg, Sweden) at three years after placement of the implants.
The study sample consisted of 30 patients who were edentulous or about to lose all remaining teeth. A total of 186 implants were placed in 9 maxillae and 22 mandibles, including one bimaxillary patient. One hundred and fifty-four of the 186 implants were immediately loaded and 32 implants were submerged. Five to 7 implants (mean of 5.8 implants) supported the prostheses in the maxilla and 4 or 5 implants (mean of 4.6 implants) in the mandible. All implants immediately loaded were placed in the incisor and premolar regions of both maxilla and mandible. The mean lengths of the implants in the maxillae and mandibles were 14.6±1.8 mm and 16.3±2.3 mm,respectively. All of 52 immediate loaded implants in the maxillae showed placement torque of more than 30 Ncm. Although 5 of 102 implants in the mandibles showed placement torque of 30 Ncm, the remaining implants showed more than 35 Ncm. Provisional implant-supported fixed prostheses were fabricated in a laboratory from an impression and were placed on the next day after the surgery. After 4 to 7 months, definitive prostheses were fabricated and placed. One implant, although still osseointegrated, was removed owing to bone resorption. In the patient, the provisional prosthesis was supported by the remaining 4 implants; thus the cumulative survival rates for implants and prostheses were 99.4% and 100%, respectively, after three years.
This clinical report suggests that immediate loading of implant-supported fixed prostheses in the edentulous maxilla and mandible can be a safe and successful treatment as long as patients are carefully and strictly selected.