バルクフィル材の機械的性質，ゲル化後の収縮率および収縮応力に及ぼす予熱方法および装置の影響．

Effect of pre-heating methods and devices on the mechanical properties, post-gel shrinkage, and shrinkage stress of bulk-fill materials.

抄録

本研究では，3 種類の樹脂系複合材料（RBC）に対して，2 種類の予熱方法を使用した場合の効果を評価した．3種類のペースト状バルクフィルRBC（VisCalor Bulk [VC]; VOCO; x-tra fil Caps [XF], VOCO; Filtek One Bulk Fill [FO], 3M）をViscalor Dispenser（VOCO）を用いて65℃に，またはCaps Warmer（VOCO）を用いて37℃，54℃，68℃に予熱した．マトリックスに挿入する前後でカプセルと空洞内の温度をモニターした。RBC挿入後30秒以内にVALO（ウルトラデント社製）の硬化灯を用いて20秒間光活性化させた．RBCのゲル化後収縮率（Shr - %），曲げ強さ（FS - MPa），弾性率（E - MPa），転化度（DC - %），ヌープ硬さ（KH - N/mm），径方向引張強度（DTS - MPa）および圧縮強度（CS - MPa）を計測（1群10検体）した。収縮応力は，3次元有限要素解析により算出した．データは一元配置分散分析，二元配置分散分析，Tukey's test (α=0.05)を用いて解析した．赤血球が空洞に挿入された後，温度は急速に低下した．赤血球の予熱は機械的性質に影響を与えなかった．FOはE，DC，KHが最も低く，VCは中間値，XFは最高値であった．DTSとCSの値は、様々な予熱方法、温度、RBCの影響を受けなかった。37℃の予熱方法では、すべてのRBCで高い収縮率が得られた。65℃に予熱されたVCは、光活性化後10分で測定した場合、最も低い応力を生じた。

This study evaluated the effect of using two different pre-heating methods on the three resin-based composite (RBCs). Three paste viscosity bulk-fill RBCs (VisCalor Bulk [VC]; VOCO; x-tra fil Caps [XF], VOCO; Filtek One Bulk Fill [FO], 3 M) were pre-heated using either a VisCalor Dispenser (VOCO) to 65 °C, or the Caps Warmer (VOCO) to 37 °C, 54 °C, or 68 °C. The temperature inside the capsules and cavity was monitored before and after insertion into the matrix. Within 30 s of inserting the RBC, they were light-activated using a VALO (Ultradent) curing light for 20 s. The post-gel shrinkage (Shr - %), Flexural Strength (FS - MPa), Elastic Modulus (E - MPa), degree of conversion (DC - %), Knoop Hardness (KH - N/mm), diametral tensile strength (DTS - MPa), and compressive strength (CS - MPa) of the RBCs were measured (10 specimens per group). The shrinkage stress was calculated using three-dimensional finite element analysis. Data were analyzed using one-way, two-way ANOVA and Tukey's test (α = 0.05). The temperature fell rapidly after the RBC was inserted into the cavity. Pre-heating the RBCs did not affect the mechanical properties. FO had the lowest E, DC, and KH values, VC had intermediate values, and XF achieved the highest values. The DTS and CS values were not affected by the various pre-heating methods, the temperature, or RBC. Pre-heating methods at 37 °C produced higher shrinkage for all RBCs. VC pre-heated to 65 °C produced the lowest stress when measured at 10 min after light activation.