Drummond James L, Thompson Michael, Super Boaz J
Department of Restorative Dentistry m/c 555, 337A College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL 60612-7212, USA.
Dent Mater. 2005 Jun;21(6):586-9. doi: 10.1016/j.dental.2004.12.002.
The purpose of this study was to measure the fractal dimensional increment of the fracture surface of six dental ceramics, and to measure the correlation of the fractal dimensional increment with fracture toughness. The six dental ceramics investigated were: a traditional porcelain (Finesse[F], Ceramco, Burlington, NJ, USA), four leucite reinforced pressable ceramics (Finesse Pressable [FP], Ceramco; Empress [E], Ivoclar; New Albany, NY, USA and two shades of OPC [OA2 and OI40], Jeneric-Pentron, MA, USA), and a lithium disilicate containing pressable ceramic ([LD] Ceramco).
The fracture surfaces examined and the measured fracture toughness (K(IC)) values are from a previous study . An impression was taken of the fracture surface, poured up in epoxy, coated with gold, a second layer of epoxy added, and then the surface polished at an angle to the fracture surface. This fracture interface (slit island) was observed in an optical microscope with an imaging system from which an image of the fracture line was digitized. The slit island perimeter was then measured using five different length rulers. The fractal dimensional increment (D*) was determined using a Richardson technique. A second experiment on three ceramics investigated whether there was a correlation between fracture toughness and the values of D* measured by an alternative technique using a confocal microscope.
Fracture toughness was well correlated with D* using either technique.
本研究旨在测量六种牙科陶瓷材料断裂表面的分形维数增量，并测量分形维数增量与断裂韧性之间的相关性。所研究的六种牙科陶瓷材料分别为：一种传统瓷（Finesse[F]，美国新泽西州伯灵顿市的Ceramco公司），四种白榴石增强可压制成型陶瓷（Finesse Pressable[FP]，Ceramco公司；Empress[E]，义获嘉公司；美国纽约州新奥尔巴尼市以及美国马萨诸塞州Jeneric-Pentron公司的两种色号的OPC[OA2和OI40]），以及一种含二硅酸锂的可压制成型陶瓷（[LD]，Ceramco公司）。
所检查的断裂表面以及测量得到的断裂韧性（K(IC)）值来自之前的一项研究。对断裂表面取模，用环氧树脂灌注，镀上金，添加第二层环氧树脂，然后以与断裂表面成一定角度的方式对表面进行抛光。在配备成像系统的光学显微镜下观察这个断裂界面（裂隙岛），从中将断裂线的图像数字化。然后使用五把不同长度的尺子测量裂隙岛周长。采用理查森技术确定分形维数增量（D*）。对三种陶瓷材料进行的第二项实验研究了断裂韧性与通过共聚焦显微镜使用另一种技术测量得到的D*值之间是否存在相关性。
使用任何一种技术，断裂韧性与D*均具有良好的相关性。
