2ステップセルフエッチングシステムにおける酸素阻害が、表面自由エネルギーおよび化学的に硬化したレジンコンポジットとの象牙質結合強度に与える影響

Effect of oxygen inhibition in two-step self-etch systems on surface free energy and dentin bond strength with a chemically cured resin composite.

抄録

酸素阻害層がある場合とない場合の2段階セルフエッチングシステムの表面自由エネルギーと象牙質接着強さを比較した．牛切歯のセルフエッチングプライマー処理象牙質表面に接着剤を塗布した後，光照射し，酸素阻害層を残すかエタノールで除去した．硬化した接着剤上に置かれた3種類の試験液の接触角を測定することで、表面自由エネルギー（γS）とその成分を求めた。また，化学的に硬化させたレジンコンポジットと接着剤との象牙質接着強さを，酸素阻害層の有無にかかわらず測定した．すべての表面において，推定表面張力成分であるγS(LW)は比較的一定であった．酸素阻害層を除去すると，ルイス塩基（γS(-)）成分は著しく減少し，ルイス酸（γS(+)）成分はわずかに増加した．2段階セルフエッチシステムの象牙質接着強さは，酸素阻害層の有無に関係なく，有意な差は認められなかった．接着剤の表面自由エネルギーは酸素阻害層の存在によって影響を受けるが，象牙質接着強さは変化しなかった．

We compared the surface free energies and dentin bond strengths of two-step self-etch systems with and without an oxygen-inhibited layer. The adhesives were applied to self-etching primer-treated dentin surfaces of bovine incisors, after which the teeth were light-irradiated and the oxygen-inhibited layer was left intact or removed with ethanol. We determined surface free energies (γS) and their components by measuring the contact angles of three test liquids placed on the cured adhesives. We also measured the dentin bond strengths of chemically cured resin composite to the adhesives, with and without the oxygen-inhibited layer. For all surfaces, the estimated surface tension component, γS(LW), was relatively constant. The Lewis base (γS(-)) component decreased significantly when the oxygen-inhibited layer was removed, whereas the Lewis acid (γS(+)) component slightly increased. The dentin bond strengths of the two-step self-etch systems did not significantly differ in relation to the presence of the oxygen-inhibited layer. Although the surface free energy of the adhesive was affected by the presence of the oxygen-inhibited layer, no changes in dentin bond strength were detected.