インプラントの上部構造接合部と歯肉辺縁の位置関係が周囲組織におよぼす影響

抄録

In an implant prosthesis, the junction between the implant neck and the superstructure has often been placed subgingivally. The aim of this study was to examine the effect of the position of the implant-superstructure junction relative to the marginal gingiva on the surrounding tissue, using periodontal paramaters.
Sixty-seven ITI Bonefit^® implants in 22 patients were selected for this study. The superstructures of implants were all fabricated using an octa system, and they were fixed to implant fixture with screws. The average observation period was 25 months. Four sites (mesial, distal, buccal, and libial sites) of each implant were checked using periodontal parameters (Plaque Index, Bleeding on Probing, Periotron Score, Probing Pocket Depth,and Probing Attachment Level). And these sites were divided into 3 groups (supragingival, equigingival, and subgingival groups) according to the position of the implant-superstructure junction relative to the gingival margin.
Result: There was no significant difference between the 3 groups in plaque index, but the subgingival group showed a significantly higher score of bleeding on probing, and in periotron score, compared with the other groups. This result suggested that the subgingival position could cause an inflammatory reaction in the surrounding tissue.