インプラント上部構造が周囲組織に及ぼす影響

―インプラント周囲炎と上部構造の固定方法との関係―

抄録

In determining long-term prognosis of dental implant treatments, control of inflammation in peri-implant tissue is an important factor. The level of inflammation in peri-implant tissues was investigated by evaluating 1)plaque accumulation,2)volume of implant crevicular fluid, and 3)marginal bone resorption around implants. Screw-retained superstructures and cemented superstructures were compared in terms of inflammatory conditions in surrounding tissues. As for statistical analysis,Mann-Whitney U-test was used for inter-group comparison. A possible correlation was evaluated by regression analysis.
The results are as follows:
1. The measurement of implant crevicular fluid volume was larger in the screw-retained prosthesis group,18 to 85(mean 42.6±6.3), than in the cemented prosthesis group,4 to 26(mean 16.3±2.3)with statistical significance(p＜0.001).
2.With screw-retained prostheses, a correlation was confirmed between disclosing staining of outer crowns and volume of implant crevicular fluid(r=0.883).
3. Three years after the delivery of superstructures, marginal bone resorption around implants was 0 to 0.80mm(0.40±0.70mm on the mesial sides,0.39±0.08mm on the distal sides, mean 0.40±0.74mm)for screw-retained prostheses and 0 to 0.80mm(0.31±0.77mm on the mesial sides,0.35±0.06mm on the distal sides, mean 0.33±0.07mm)for cemented prostheses, indicating no statistical difference between the two groups.
4. A correlation was not found between marginal bone resorption around implants and disclosing staining of outer crowns as well as volume of implant crevicular fluid.
Peri-implant inflammation was more significant around screw-retained superstructures, which suggests that it is largely affected by plaque accumulated in slight gaps between inner crowns and outer crowns.