Maciel K T, Carvalho R M, Ringle R D, Preston C D, Russell C M, Pashley D H
Department of Oral Biology, Medical College of Georgia, School of Dentistry, Augusta 30912-1129, USA.
J Dent Res. 1996 Nov;75(11):1851-8. doi: 10.1177/00220345960750110601.
During resin-bonding procedures, dentin surfaces are treated with acidic conditioners to remove the smear layer and decalcify the surface to expose the collagen fibrils of the underlying matrix. These decalcified surfaces are then either air-dried or treated with dehydrating solvents, procedures which may modify the physical properties of the dentin matrix. The purpose of this study was to evaluate the effects of dehydration on the stiffness of the decalcified dentin matrix. Small (8 x 1.7 x 0.9 mm) beams of dentin were prepared from mid-coronal dentin of extracted human molars. The ends were covered with varnish for protection, and the specimens were placed in 0.5 M EDTA for 5 days to decalcify. The stiffness was measured by both the cantilever technique and by conventional stress-strain testing. Specimens tested by the cantilever technique were sequentially exposed to water, acetone, alcohol, HEMA, and glutaraldehyde. Specimens tested by conventional stress-strain testing were exposed either to water, acetone, or HEMA, or were allowed to air-dry. The results indicate that the stiffness of decalcified human dentin matrix is very low (ca. 7 MPa), if the specimens are wet with water. As they are dehydrated, either chemically in water-miscible organic solvents or physically in air, the stiffness increases 20- to 38-fold at low strains or three- to six-fold at high strains. These increases in modulus were rapidly reversed by rehydration in water. Exposure to glutaraldehyde also produced an increase in stiffness that was not reversible when the specimens were placed back in water.
在树脂粘结过程中，牙本质表面要用酸性调节剂处理，以去除玷污层并使表面脱钙，从而暴露出下方基质的胶原纤维。然后，这些脱钙表面要么风干，要么用脱水溶剂处理，这些操作可能会改变牙本质基质的物理性质。本研究的目的是评估脱水对脱钙牙本质基质硬度的影响。从拔除的人类磨牙的牙冠中部牙本质制备小（8×1.7×0.9毫米）梁状牙本质样本。两端用清漆覆盖以作保护，样本置于0.5M乙二胺四乙酸（EDTA）中5天进行脱钙。通过悬臂技术和传统的应力应变测试来测量硬度。通过悬臂技术测试的样本依次暴露于水、丙酮、酒精、甲基丙烯酸羟乙酯（HEMA）和戊二醛。通过传统应力应变测试的样本暴露于水、丙酮或HEMA，或者使其风干。结果表明，如果样本用水湿润，脱钙的人类牙本质基质的硬度非常低（约7兆帕）。当它们通过与水混溶的有机溶剂进行化学脱水或在空气中进行物理脱水时，在低应变下硬度增加20至38倍，在高应变下增加3至6倍。通过在水中再水化，这些模量的增加迅速逆转。暴露于戊二醛也会使硬度增加，当样本放回水中时这种增加是不可逆的。
