Polyzois G L, Tarantili P A, Frangou M J, Andreopoulos A G
Department of Removable Prosthodontics, University of Athens and National Technical University of Athens, Athens, Greece.
J Prosthet Dent. 2000 May;83(5):572-7. doi: 10.1016/s0022-3913(00)70017-5.
Facial prostheses worn over an extended time are exposed to various environmental factors, including sebaceous oils (sebum) and perspiration.
This study investigated the physical properties of tensile strength and modulus, elongation, tear strength, hardness, weight, and color change, of a silicone facial elastomer after immersion for 6 months in simulated sebum and perspiration at 37 degrees C.
Specimens made of Episil silicone elastomer were immersed in simulated alkaline or acidic perspiration as well as in sebum. Tensile and tear tests were conducted according to ISO specifications no. 37 and 39, respectively, in a Monsanto testing machine. Shore A hardness measurements were run according to ASTM D 2240. Weight changes were followed at 5, 15, 30, and 180 days, and color changes were determined in the CIE LAB system using a tristimulus colorimeter.
An improvement of mechanical properties for specimens immersed in acidic perspiration was attributed to facilitation of the propagation of cross-linking reaction during aging of the silicone samples. Some weight increase was observed for the specimens immersed into the aqueous solution, whereas for those immersed in sebum, weight loss was recorded, probably because of extraction of some compounds. In this latter case, the color change was lower than that corresponding to simulated perspiration.
The silicone specimens aged for a period, which simulates 1.5 years of clinical service, showed minimal changes with respect to the properties studied.
长时间佩戴的面部假体暴露于各种环境因素中，包括皮脂和汗液。
本研究调查了一种硅酮面部弹性体在37摄氏度下于模拟皮脂和汗液中浸泡6个月后的拉伸强度、模量、伸长率、撕裂强度、硬度、重量和颜色变化等物理性能。
由Episil硅酮弹性体制成的试样浸泡在模拟碱性或酸性汗液以及皮脂中。分别根据ISO标准第37号和第39号在孟山都试验机上进行拉伸和撕裂试验。根据ASTM D 2240进行邵氏A硬度测量。在第5、15、30和180天跟踪重量变化，并使用三色刺激比色计在CIE LAB系统中测定颜色变化。
浸泡在酸性汗液中的试样机械性能有所改善，这归因于硅酮样品老化过程中交联反应的传播得到促进。浸泡在水溶液中的试样观察到一些重量增加，而浸泡在皮脂中的试样记录到重量损失，可能是由于一些化合物的萃取。在后一种情况下，颜色变化低于模拟汗液对应的变化。
经过一段模拟1.5年临床使用时间老化的硅酮试样，在所研究的性能方面变化极小。
