Polyzois Gregory, Lyons Karl
From the *Department of Prosthodontics, Dental School, University of Athens, Athens, Greece; and †Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
J Craniofac Surg. 2014 Jul;25(4):1217-21. doi: 10.1097/SCS.0000000000000871.
The purpose of this study was to investigate the effect of natural aging after storage in the dark for 1 year and material type on Shore A hardness of 2 silicone prosthetic elastomers.
The silicone elastomers tested were low- and high-temperature vulcanizing materials, namely, Premium and Silasto 30, respectively. Ten samples, 25 × 25 × 10 mm3, from each silicone were made and stored in sealed glass containers in the dark. Shore A hardness was measured according to the American Society for Testing Materials specification D2240. Three recordings were made on each sample at baseline and then weekly for 12 months (quadruplicate per mo). Data were analyzed by general linear modeling for repeated measures and Student-Newman-Keuls test for post hoc comparisons at α = 0.05.
General linear modeling analysis indicated a significant influence of either silicone type (F = 229.5, P = 0.0001) or natural aging (F = 105.9, P = 0.0001) or their interaction (F = 27.6, P = 0.0001) on Shore A hardness values. For Premium and Silasto 30, Shore A hardness ranged from 16.9 to 26.0 and 32.0 to 36.3, respectively. The elastomers showed a trend to increase hardness over natural aging, which was significant (Premium) or not (Silasto 30), depending on the material and time intervals.
Premium silicone showed a significant hardness increase after 1 year of natural aging in the dark, reaching a convergent value approximately 6 months from the onset, whereas Silasto 30 hardness remained stable during this period. Both elastomers showed Shore A hardness values within clinical acceptable limits after aging.
本研究旨在探讨在黑暗中储存1年后自然老化以及材料类型对2种硅酮假体弹性体邵氏A硬度的影响。
所测试的硅酮弹性体分别为低温和高温硫化材料，即Premium和Silasto 30。从每种硅酮材料制备10个尺寸为25×25×10 mm³的样本，并将其储存在密封玻璃容器中置于黑暗环境。根据美国材料与试验协会规范D2240测量邵氏A硬度。在基线时对每个样本进行3次记录，然后在12个月内每周记录一次（每月重复4次）。采用重复测量的一般线性模型进行数据分析，并使用Student-Newman-Keuls检验进行事后比较，α = 0.05。
一般线性模型分析表明，硅酮类型（F = 229.5，P = 0.0001）、自然老化（F = 105.9，P = 0.0001）或它们的相互作用（F = 27.6，P = 0.0001）对邵氏A硬度值均有显著影响。对于Premium和Silasto 30，邵氏A硬度分别为16.9至26.0以及32.0至36.3。弹性体在自然老化过程中呈现出硬度增加的趋势，根据材料和时间间隔的不同，这种增加在Premium中显著，而在Silasto 30中不显著。
Premium硅酮在黑暗中自然老化1年后硬度显著增加，大约从开始6个月后达到收敛值，而在此期间Silasto 30的硬度保持稳定。两种弹性体在老化后邵氏A硬度值均在临床可接受范围内。
