Lai J H, Hodges J S
LAI Laboratories, Inc., Burnsville, MN, USA.
Dent Mater. 1999 Nov;15(6):450-5. doi: 10.1016/s0109-5641(99)00074-3.
Maxillofacial prostheses are commonly fabricated using dental stone molds. However, for evaluating physical properties, maxillofacial materials are most often cured in metal molds. A-2186 is a silicone-based maxillofacial prosthetic material. Because its cure may be inhibited by traces of impurities, its physical properties may be different when it contains additives and is cured in dental stone molds, compared to when it is cured in metal molds without additives. This study's purpose is to determine and compare the physical properties of A-2186 cured in stainless steel molds and stone molds. The effects of additives and cure conditions on the physical properties were also studied.
Hardness, tensile strength, ultimate elongation, and tear strength of A-2186 cured in dental stone molds, stainless steel molds, and with and without additives were determined. The bonding strength of A-2186 to four adhesives was determined by the peel test. All comparisons were made using analysis of variance (ANOVA).
Hardness, tensile strength and ultimate elongation of A-2186 cured in stainless steel molds are significantly higher than those cured in stone molds. Adding a small amount of a pigment, a kaolin and a fiber reduces hardness, tensile strength, ultimate elongation and tear strength. Except for Hydrobond, the bond strength of the adhesives to A-2186 was not significantly affected by the cure conditions and additives.
Physical properties of A-2186 are affected by the additives commonly used in fabricating maxillofacial prostheses, and use of stone molds for curing degrades A-2186's mechanical properties. In fabricating clinical prostheses, special attention should be exercised to avoid contamination of A-2186 with impurities that could inhibit curing and produce inferior prostheses.
颌面修复体通常使用牙科石膏模型制作。然而，为了评估物理性能，颌面材料大多在金属模具中固化。A - 2186是一种硅基颌面修复材料。由于其固化可能会受到微量杂质的抑制，所以与在无添加剂的金属模具中固化相比，当它含有添加剂并在牙科石膏模具中固化时，其物理性能可能会有所不同。本研究的目的是测定并比较在不锈钢模具和石膏模具中固化的A - 2186的物理性能。同时还研究了添加剂和固化条件对物理性能的影响。
测定了在牙科石膏模具、不锈钢模具中固化以及添加和不添加添加剂情况下A - 2186的硬度、拉伸强度、极限伸长率和撕裂强度。通过剥离试验测定了A - 2186与四种粘合剂的粘结强度。所有比较均采用方差分析（ANOVA）。
在不锈钢模具中固化的A - 2186的硬度、拉伸强度和极限伸长率显著高于在石膏模具中固化的。添加少量颜料、高岭土和纤维会降低硬度、拉伸强度、极限伸长率和撕裂强度。除了Hydrobond，粘合剂与A - 2186的粘结强度不受固化条件和添加剂的显著影响。
A - 2186的物理性能受颌面修复体常用添加剂的影响，使用石膏模具固化会降低A - 2186的机械性能。在制作临床修复体时，应特别注意避免A - 2186被可能抑制固化并导致修复体质量不佳的杂质污染。
