Viscoelastic properties of demineralized dentin matrix
Viscoelastic properties of demineralized dentin matrix
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DOI：
10.1016/s0109-5641(03)00016-2
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发表时间：
2003-12-01
期刊：
影响因子：
5
通讯作者：
Tay, FR
中科院分区：
文献类型：
--
作者：
Pashley, DH;Agee, KA;Tay, FR
目标.评价脱矿牙本质基质的粘弹性。对拉伸和应变下的基质进行了应力松弛研究，或对拉伸和压缩下的蠕变进行了研究。方法。从未萌出的人类第三磨牙中制备中冠牙本质盘。对于应力松弛或拉伸蠕变实验，试样厚度为0.5 mm，对于压缩蠕变研究，试样厚度为0.2-0.3 mm。从牙本质盘制备“I”型梁试样，并将中间区域在0.5M EDTA（pH 7）中脱矿4天。将试样保持在水中的微型摩擦夹具中，并以100 μ m s（-1）拉伸至5、10、15或20%的应变，然后保持10分钟以跟踪应力随时间的衰减。蠕变测定脱矿牙本质浸泡在水中的拉伸和压缩。使用LVDT接触探针以0.02-0.5 N的载荷测量压缩蠕变。将应变数据转换为顺应性-时间曲线（应变/应力），并表示为总顺应性（J（t））、瞬时弹性顺应性（J（o））、延迟弹性顺应性（J（R））和粘性响应（t/eta）或蠕变。牙本质基质同时表现出应力松弛和蠕变行为。应力松弛和拉伸蠕变与应变无关，但压缩蠕变速率与压缩应变呈负相关。蠕变值在低压缩应变下约为10%，但在高应变下逐渐下降至1%。顺应性-时间曲线随着压力的下降而下降，并越来越接近。然而，无论应变如何，拉伸蠕变约为3%。牙本质基质表现出粘弹性，但不是线性的。粘弹性的在低压缩载荷下，基质的相对高的蠕变速率可能导致功能下树脂粘结牙齿中渗透不良的混合层的粘性变形。2003年牙科材料学院。由爱思唯尔有限公司出版。保留所有权利。
Objectives. To evaluate the viscoelastic properties of demineralized dentin matrix. Stress-relaxation studies were done on matrices in tension and strain elongation or creep studies were done in both tension and compression.Methods. Mid-coronal dentin disks were prepared from extracted unerupted human third molars. Disks were 0.5 mm thick for stress-relaxation or tensile creep experiments and 0.2-0.3 mm thick for compressive creep studies. 'I' beam specimens were prepared from dentin disks and the middle region was demineralized in 0.5 M EDTA (pH 7) for 4 days. The specimens were held in miniature friction grips in water and pulled at 100 mum s(-1) to strains of 5, 10, 15 or 20% and then held for 10 min to follow the decay of stress over time. Creep was determined on demineralized dentin immersed in water in tension and in compression. Compressive creep was measured using an LVDT contact probe with loads of 0.02-0.5 N. Strain data were converted to compliance-time curves (strain/stress) and expressed as total compliance (J(t)), instantaneous elastic compliance (J(o)), retarded elastic compliance (J(R)) and viscous response (t/eta) or creep.Results. The dentin matrix exhibits both stress-relaxation and creep behavior. Stress-relaxation and tensile creep were independent of strain but compressive creep rates were inversely related to compressive strain.-Creep values were about 10% at low compressive strains, but fell progressively to 1% at high strains. Compliance-time curves fell with stress and came closer together. However, tensile creep was about 3% regardless of the strain.Significance. The dentin matrix exhibits viscoelastic properties, but is not linearly. viscoelastic. The relatively high creep rates of the matrix under low compressive loads may cause viscous deformations in poorly infiltrated hybrid layers in resin-bonded teeth under function. 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.