【摘要】 目的评价不同冷热循环次数对复合树脂粘结抗剪切强度的影响。方法选30颗健康新鲜的恒磨牙,分为A、B、C 3组,每组10颗牙,每颗牙利用颊、舌、近中、远中四个面,在相应牙面的冠中1/3的平整处,用复合树脂制作直径2 mm,高3 mm的圆柱体,共40个面的试件。A组作为对照组,B、C组分别经100次和500次的冷热循环,测定A、B、C各组的抗剪切力,计算抗剪切强度。体视显微镜下观察受检试件断面的断裂类型。结果 3组抗剪切强度分别为16.36、12.56和10.91 MPa,A组和B组的剪切强度差别无统计学意义(P>0.05);A组和B组的抗剪切强度大于C组,差别有统计学意义(P<0.05)。A、B、C 3组断裂模式差别无统计学意义(P>0.05)。结论复合树脂粘结经冷热循环500次后,抗剪切力的强度下降。更多还原

【Abstract】 Objective To evaluate the shear force of composite resin after cyclic mechanical loading.Methods Thirty healthy fresh molars were divided into Group A,B and C,10 in each group.On each of the buccal,lingual,mesial,and distal tooth surfaces and the corresponding tooth surface of 1/3 of the crown,a total of 40 surface cylinder samples were prepared with 2 mm in diameter,3 mm in height.Group A was treated as control,Group B and C respectively 100 and 500 psychro-thermal cycles.The shear force in each group was measured and shear strength calculated.The type of specimen fracture section was observed under the stereomicroscope(4×25).Results Shear bond strength of the three groups was 16.36,12.56 and 10.91 MPa,respectively.Group A and B showed no significant difference in the shear strength(P>0.05) but both groups showed significantly greater shear strength than Group C(P<0.05).The three groups showed no significant difference in fracture patterns(P>0.05).Conclusion The anti-shear strength of composite resin adhesives decreases after 500 thermal cycles.更多还原