歯列矯正用接着剤の硬度に及ぼす組成の影響

Effects of composition on the hardness of orthodontic adhesives.

抄録

接着剤をプレコートしたブラケットシステムの改良が進んでいるが，接着剤残渣の除去は依然として問題である．本研究では，プレコートされた接着剤と他の市販接着剤の硬度およびメンテナンス性を比較した．また，ブラケットを0.5 mm移動させるのに必要な力を測定し，ブラケットとウシエナメル質の接着状態を電界放出型走査電子顕微鏡で観察した．プレコート接着剤のKnoop硬度値は，市販のレジンコンポジット接着剤よりも低く，硬度はレジンマトリックス中のフィラー量に依存した．デバイスの位置を維持する能力は，レジンマトリクスの組成に依存すると思われる．フィラーが少なく，マトリックスが多いプレコート接着剤は光硬化性であり，残存樹脂を容易に除去できる可能性がある．

Although there have been improvements in bracket systems precoated with adhesive, removal of adhesive remnants continues to be problematic. This study compared the hardness and maintainability of precoated adhesive with other commercial adhesives. Knoop hardness values were measured after light- or chemical-induced initial curing, immersion in distilled water at 37°C for 24 h and 1,000 and 10,000 thermal cycles after 24 h. Additionally, the forces required to move brackets by 0.5 mm were measured during bracket positioning, and brackets bonded to bovine enamel were examined by field-emission scanning electron microscopy. The Knoop hardness values of the precoated adhesives were lower than those of commercial resin composite adhesives, and hardness was dependent on the amount of filler in the resin matrix. The ability to maintain the device position may depend on the resin matrix composition. Precoated adhesives with less filler and more matrix material are light curable, and remnant resin may be easily removed.