ジルコニアへの接着。実験的手法を用いた透光性とカスプの傾斜の効果

Bonding to zirconia: Effects of translucency and cusp inclinations using an experimental methodology.

• Chang-Yuan Zhang
• Hao Yu
• Xin-Wen Tong
• Hui Cheng

抄録

目的:

ジルコニアと自己接着性レジンセメント（SARC）の微小せん断接着強さ（μSBS）に及ぼす透光性と尖端の傾きの影響を調査する。

PURPOSE: To investigate the effects of translucency and cusp inclination on the micro-shear bond strength (µSBS) of zirconia to self-adhesive resin cement (SARC).

研究方法:

厚さ1.0 mmのU字型のジルコニア試験片60個を，異なる歯牙傾斜を模擬した3つの平面（0°，20°，30°）で構成し，高，中，低の透光性をもつジルコニアブロック（n=20）から作製した．SARCを試料に接着し，40秒間光硬化させた。µSBSは，クロスヘッドを備えた万能試験機を用いて0.5 mm/minの速度で試験を行い，実体顕微鏡（50倍）を用いて破壊モードを観察した。統計解析には，二元配置分散分析とポストホックTukey's honest significant difference検定を用いた（α=0.05）。

METHODS: Sixty U-shaped zirconia specimens with 1.0 mm thickness consisting of three planes (0°, 20°, and 30°) simulating different cusp inclinations were fabricated from zirconia blocks of high, moderate, and low translucency (n=20). SARC was bonded to the specimen and light-cured for 40 s. The µSBS was tested using a universal testing machine with a cross-head at a speed of 0.5 mm/min and fracture mode was observed using a stereomicroscope (×50). Two-way analysis of variance followed by a post hoc Tukey's honest significant difference test was used for the statistical analyses (α=0.05).

結果:

テスト群では，さまざまなμSBS値が認められた（7.1～14.9MPa）。同じ透光性のジルコニアでは，0°面のμSBS値が20°および30°面のμSBS値よりも有意に高かった（いずれもp<0.05）。同じカスプ傾斜のジルコニアでは，高透光性ジルコニアのμSBS値は中透光性および低透光性ジルコニアのμSBS値よりも有意に高かった（いずれもp<0.05）。カスプの傾きと透光性の間には有意な相互作用はなかった（p=0.525）。破壊モードは，接着性破壊が83.33％，混合性破壊が11.11％，凝集性破壊が5.56％であった．

RESULTS: Varied µSBS values were found in the test groups (7.1-14.9 MPa). Within the zirconia of the same translucency, the µSBS value of the plane 0°specimen was significantly higher than that of the 20° and 30° planes (all p<0.05). Within the zirconia of the same cusp inclination, the µSBS value of highly translucent zirconia was significantly higher than that of moderate and low translucent zirconia (all p<0.05). There was no significant interaction between cusp inclination and translucency (p=0.525). Among the fracture modes, 83.33% were adhesive failure, 11.11% mixed failure, and 5.56% were cohesive failure.

おわりに:

ジルコニアとSARCのμSBSには透光性とカスプの傾きが大きく影響する。透光性が高いほどμSBSの値は大きく，カスプ傾斜が大きいほどμSBSの値は小さかった。

CONCLUSIONS: Translucency and cusp inclination significantly affect the µSBS of zirconia to SARC. The higher the translucency, the greater are the µSBS values; the higher the cusp inclination, the lower are the µSBS values.