Lee Ahreum, Swain Michael, He Lihong, Lyons Karl
Professional practice fellow, Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
Professor and Head of Biomaterials, Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
J Prosthet Dent. 2014 Dec;112(6):1399-405. doi: 10.1016/j.prosdent.2014.08.002. Epub 2014 Oct 11.
The wear behavior of human enamel that opposes different prosthetic materials is still not clear.
The purpose of this in vitro study was to investigate and compare the friction and wear behavior of human tooth enamel that opposes 2 indirect restorative materials: lithium disilicate glass ceramic and Type III gold.
Friction-wear tests on human enamel (n=5) that opposes lithium disilicate glass ceramic (n=5) and Type III gold (n=5) were conducted in a ball-on-flat configuration with a reciprocating wear testing apparatus. The wear pairs were subjected to a normal load of 9.8 N, a reciprocating amplitude of approximately 200 μm, and a reciprocating frequency of approximately 1.6 Hz for up to 1100 cycles per test under distilled water lubrication. The frictional force of each cycle was recorded, and the corresponding friction coefficient for different wear pairs was calculated. After wear testing, the wear scars on the enamel specimens were examined under a scanning electron microscope.
Type III gold had a significantly lower steady-state friction coefficient (P=.009) and caused less wear damage on enamel than lithium disilicate glass ceramic. Enamel that opposed lithium disilicate glass ceramic exhibited cracks, plow furrows, and surface loss, which indicated abrasive wear as the prominent wear mechanism. In comparison, the enamel wear scar that opposed Type III gold had small patches of gold smear adhered to the surface, which indicated a predominantly adhesive wear mechanism.
A lower friction coefficient and better wear resistance were observed when human enamel was opposed by Type III gold than by lithium disilicate glass ceramic in vitro.
与不同修复材料相对的人类牙釉质的磨损行为仍不明确。
本体外研究的目的是调查和比较与两种间接修复材料（二硅酸锂玻璃陶瓷和III型金）相对的人类牙釉质的摩擦和磨损行为。
使用往复式磨损试验装置，以球-平面配置对与二硅酸锂玻璃陶瓷（n = 5）和III型金（n = 5）相对的人类牙釉质（n = 5）进行摩擦磨损试验。在蒸馏水润滑下，磨损副承受9.8 N的法向载荷、约200μm的往复振幅和约1.6 Hz的往复频率，每次试验最多进行1100个循环。记录每个循环的摩擦力，并计算不同磨损副的相应摩擦系数。磨损试验后，在扫描电子显微镜下检查牙釉质标本上的磨损痕迹。
III型金的稳态摩擦系数显著更低（P = .009），并且与二硅酸锂玻璃陶瓷相比，对牙釉质造成的磨损损伤更小。与二硅酸锂玻璃陶瓷相对的牙釉质出现了裂纹、犁沟和表面损失，这表明磨粒磨损是主要的磨损机制。相比之下，与III型金相对的牙釉质磨损痕迹表面附着有小块金涂抹物，这表明主要磨损机制是粘着磨损。
在体外，当人类牙釉质与III型金相对时，观察到的摩擦系数比与二硅酸锂玻璃陶瓷相对时更低，耐磨性更好。
