Effect of Rheological Properties of Resin Composite Pastes on Marginal Adaptation of the Restoration in Dentin Cavity

通过测量圆柱形牙本质腔内收缩间隙宽度来确定8种市购树脂复合材料的边际适应性，分别为Clearfil APX、Estelite、Estio LC、Litefil IIA、Prodigy、Progress、Silux Plus和Z-100。采用由05M EDTA、35%单甲基丙烯酸甘油酯溶液和Clearfil Photo Bond组成的实验牙本质键合体系对牙本质腔壁进行处理。Clearfil APX、Estelite和Silux Plus这三种复合材料完全阻止了收缩间隙的形成。8种复合材料的牙本质平面间隙宽度和抗拉结合强度差异不显著（p> . 0 0. 5）。通过安装在VT550粘度测试仪上的锥板粘度传感器系统测定了8种复合膏体的触变性指数[TI]。复合膏体在24+1C中保存至少24小时，然后在37+1C恒温板传感器上转移。10.68 s-1剪切速率下的TI与测量的间隙宽度呈显著相关（r2=0.822）。此外，通过安装在Rheosiress RS75上的截锥和平板粘度传感器系统测量了8种复合材料的屈服强度和触变性随转速的变化。复合膏体和平板传感器的条件控制与TI的测量一致。8种复合材料的TI与测量的间隙宽度呈显著相关（r2=0.757）。复合浆料的流变性能可以预测复合浆料在牙本质腔内的边缘适应性。

Marginal adaptation of eight commercially available resin composites, Clearfil APX, Estelite, Estio LC, Litefil IIA, Prodigy, Progress, Silux Plus and Z-100, were detemiined by measurement of the contraction gap width in a cylindrical dentin cavity. The cavity walls were treated with the experimental dentin bonding system consisting of 05M EDTA, 35% glyceryl mono-methacrylate solution and Clearfil Photo Bond. Three composites, Clearfil APX, Estelite and Silux Plus, prevented the contraction gap formation completely. There was not significantly deference (p>0.O5) between the gap width and tensile bond strength to flat dentin surface of the eight composites.The thixoiropy indexes [TI] of the eight composite pastes depending on a lime were detemiined by a cone and plate viscometry sensor system mounted in a Viscotester VT550.The composite pastes were stored, in 24+1C at least for 24 hours, and then transferred on the thermostatic plate senser at 37+1C. The TI at 10.68 s-1 of a shear rate correlated significantly (r2=0.822) with the measured gap width. Furthermore the yield strengths and thixotropy depending on a rotalive velocity of the eight composites were measured by a truncated cone and plate viscometry senser system mounted in a Rheosiress RS75.Condition of the composite pastes and plate senser were controlled as same as measuring of the TI. The TI of the eight composites correlated significantly (r2=0.757) with the measured gap width. The rheological properties of the composite pastes may predict the marginal adaptation of the polymerized composites in dentin cavity.