光强变化对光固化和双重固化树脂粘结剂粘结强度的影响

Effects of cure-light intensity on the bond strength of light-cure and dual-cure resin adhesives

目的:比较随着光照深度的增加,穿透牙本质后的固化光光强变化对光固化(SE)和双重固化(DC)树脂粘结剂与牙本质粘结强度的影响。方法:选择40个新鲜无龋离体恒磨牙,暴露牙合面牙本质后随机分为SE组和DC组(n=20),分别用相应粘结剂处理后,将咬合面两两对接,从近中方向光照10 s(650 m W/cm^2),制作成牙本质粘结样本(n=10)。37℃水中保存24 h后,将两组粘结试样沿光照方向垂直粘结界面切出微拉伸样本(1 mm×1 mm),根据光穿透牙本质深度,每组再分为4个亚组(由浅及深分别为L1~L4),测试其粘结强度(m TBS),以及光穿透不同厚度牙本质后的光强变化,并进行统计分析。结果:光强度随着穿透牙本质厚度增加而降低。穿透1、2 mm牙本质后,光强(m Wcm^(-2))从645±14下降至114±28和28±11。L1~L4组粘结强度(MPa),SE组分别为:13.22±8.64、7.49±3.88、0、0;DC组分别为:11.25±4.11、9.69±5.07、8.13±4.88、6.83±3.53。SE和DC组间L1与L2粘结强度无统计学差异(P>0.05)。结论:随着光穿透牙本质深度的增加,SE和DC与牙本质的粘结强度均降低。在弱光固化情况下,DC优于SE。

AIM： To evaluate the intensity of cure - light after penetrating dentin, and to compare the effects of cure- light intensity on the micro- tensile bond strength of light- cure and dual - cure dental adhesives. METHODS： A dual-cure （Clearfil DC BOND, DC） and a light-cure （Clearfil SE BOND, SE） resin adhesive were used. The superficial dentin of occlusal surface of 40 molars was exposed and applied with SE and DC respectively, then bonded together by light-cure for 10 seconds （650 mW/cm2） from mesial dejection. The bond specimens （n = 10） were kept in 37 ~C water for 24 h and cut into sticks （ bonding area 1 mm x 1 ram） along the direction of light-cure （from shallowness to profunda ：L1 -L4）. The bond strength（mTBS） was measured with Micro-Tensile Tester. The in- tensity of cure-light after penetrating dentin was also measured. The statistical analysis was performed using SPSS 11. 0. RESULTS： After penetrating dentin of 1 mm and 2 mm, the intensity of cure- light decreased from 645 ±14 mWcm-2 to 114 ± 28 mWcm-2 and 28 ± 11 mWcm-2 respectively. The mTBS were 13.22± 8.64 MPa （L1） , 7.49 ±3.88 MPa （I2） and 0 MPa （L3 and IA） for SE,11.25 ±4.11 MPa （L1） , 9.69 ±5.07 MPa （L2） , 8.13 ±4.88 MPa （L3）, and 6.83 ± 3.53 MPa （IA） for DC,respectively（ SE vs DC, at L1 and L2, P 〉 0.05; at L3 and I_A, P 〈 0. 05）. CONCLUSION ： The mTBS of SE and DC decreases with the increase of cure - hght penetrating dentin depth . When subdued light is used SE performed better than DC.