Yamamoto Takatsugu, Hanabusa Masao, Kimura Saori, Momoi Yasuko, Hayakawa Tohru
Department of Operative Dentistry, Tsurumi University School of Dental Medicine.
Department of Dental Engineering, Tsurumi University School of Dental Medicine.
Dent Mater J. 2018 Jan 30;37(1):87-94. doi: 10.4012/dmj.2017-047. Epub 2017 Sep 7.
The objective of this study was to investigate changes in polymerization stress and elastic modulus for light-cured bulk-fill resin composites following irradiation. Crack analysis was applied to obtain the stresses for 24 h after irradiation, which were calculated from the lengths of cracks in a glass mold bonded to the composites. The elastic modulus was repeatedly measured by nano-indentation tests performed over 24 h. The lengths of the cracks, the interfacial stress, and the elastic modulus were significantly affected by the material and time after irradiation (p<0.01). The stress and elastic modulus continued to increase for more than 6 and 1 h, respectively (p<0.05). Strong relationships (r>0.85) were revealed between the stress and elastic modulus. The bulk-fill resin composites generated smaller stresses than a flowable resin composite reported to generate relatively low stress. Post-irradiation polymerization during the first 1 h is a major determinant for the magnitude of stress.
本研究的目的是调查光固化大块充填树脂复合材料辐照后聚合应力和弹性模量的变化。采用裂纹分析法获取辐照后24小时的应力，该应力由粘结在复合材料上的玻璃模具中的裂纹长度计算得出。通过在24小时内进行的纳米压痕试验反复测量弹性模量。裂纹长度、界面应力和弹性模量受材料和辐照后时间的显著影响（p<0.01）。应力和弹性模量分别在6小时和1小时以上持续增加（p<0.05）。应力和弹性模量之间呈现出强相关性（r>0.85）。大块充填树脂复合材料产生的应力比据报道产生相对较低应力的可流动树脂复合材料更小。辐照后1小时内的后聚合是应力大小的主要决定因素。
