Axial shrinkage-stress depends upon both C-factor and composite mass
Axial shrinkage-stress depends upon both C-factor and composite mass
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DOI：
10.1016/j.dental.2007.08.007
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发表时间：
2008-01-01
期刊：
影响因子：
5
通讯作者：
Satterthwaite, Julian D.
中科院分区：
文献类型：
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作者：
Watts, David C.;Satterthwaite, Julian D.
目标。为BIOMAN仪器[1]测量C因子(粘结/非粘结面积比)的系统变化，通过自由悬臂梁偏转记录应力，柔度1.5微米/兆帕，测量聚合应力并建立数学模型。研究了一种含57%(v/v)450 nm填料的光固化树脂复合材料(RZD103；Ivoclar)。表面：构成BIOMAN测试室的玻璃板和钢棒端部垂直于测量的轴向应力方向，变化如下：(A)棒直径(Phi)，以1 mm为增量从1到10 mm(间隙高度为0.8 mm)；以及(B)16级间隙高度(H)，从0.05到1.50 mm(Phi=10 mm)。对于每个h和phi组合，给定C因子从600 mW cm(-2)的40 S照射开始，在23℃下进行光聚合(n=3)，记录收缩应力1h。收缩应力(S-西格玛)直接绘制为h、Phi和C的函数，也是单位复合质量的函数(S(西格玛)g(-1))。应用ANOVA和Tukey的统计方法。A系列直径变化：随着C因子从0.6增加到6，S-西格玛从45 Mpa精确地指数下降到8 Mpa。随着C因子从3增加到100，S-西格玛从1增加到8 Mpa。由于复合质量同样起主导作用，单位复合质量的应力变化曲线(S(σ)g(-1))分离了这些影响，证实了渐进式的离轴应力释放，其意义越来越大。(I)确定了推荐使用的h=0.8和Phi=10 mm的值[1]。每一台用于测量S-西格玛的实验室仪器都必须在仪器设计中体现特定的C因素和顺应值。(Ii)构型(C)因素被认为是影响修复体洞和粘接间隙内收缩应力表现的重要参数。然而，在将收缩科学转化为具体的临床建议时，必须同样考虑恢复性质量。(C)2007年牙科材料学会。爱思唯尔有限公司出版。保留所有权利。
Objectives. To measure and then mathematically model polymerization stress-dependence upon systematic variations of C-factor (bonded/unbonded area ratio) for the Bioman instrument [1], recording stress by free cantilever-beam deflection; compliance 1.5 mu m/MPa.Methods. A light-cured resin-composite (RZD103; Ivoclar) with 57% (v/v) 450 nm filler was studied. Facing surfaces: glass slab and steel rod-end, constituting the Bioman test chamber, being perpendicular to the measured axial stress-direction, were varied: (a) with rod-diameters (phi), from 1 to 10 mm in 1 mm increments (with 0.8 mm gap height); and then (b) with gap heights (h) in 16 steps from 0.05 to 1.50 mm (with phi = 10 mm). For each h and phi combination, giving C-factors ranging from 0.6 to 100, shrinkage-stress was recorded for 1 h from start of 40 s irradiation at 600 mW cm(-2) for photo-polymerization at 23 degrees C (n = 3). Shrinkage-stress (S-sigma) was plotted directly as functions of h, phi, and C and also per unit composite mass, (S(sigma)g(-1)). ANOVA and Tukey's statistics were applied.Results. Series A-diameter variation; with C-factor increasing from 0.6 to 6, gave an exact exponential decrease in S-sigma from 45 to 8 MPa. Series B-height variation; with C-factor increasing from 3 to 100, gave increasing S-sigma from 1 to 8MPa. Since composite mass played an equally dominant role, plots of stress-variations per unit composite mass, (S(sigma)g(-1)) separated these effects, confirming progressive off-axial stress-relief with increasing h.Significance. (i) Values of h = 0.8 and phi = 10 mm, recommended [1] for Bioman use, were confirmed as appropriate. Every lab instrument for measuring S-sigma necessarily embodies specific C-factors and compliance values in the instrument design. (ii) Configuration (C) factor is recognized as an important parameter affecting manifestation of shrinkage-stress within restorative cavities and luting gaps. However, the restorative mass must equally be considered when translating shrinkage-science into specific clinical recommendations. (c) 2007 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.