Johnson W T, Hembree J H, Weber F N
Am J Orthod. 1976 Nov;70(5):559-66. doi: 10.1016/0002-9416(76)90280-3.
A total of 210 double-width stainless steel edgewise brackets with retentive lip bases were bonded to bovine incisors with seven commercially available direct-bonding materials. Ten samples for each of the seven direct-bonding materials were tested for shear strength using the Instron Universal Testing Instrument. The samples were tested after 1 day, 1 month, and 3 months of immersion in 30 per cent physiologic saline solution. The mean shear strength of each direct-bonding material at each time interval was compared statistically to the mean shear strength of each of the materials at each time interval with a matched 1 test. The same test was used to determine whether there had been a significant change in mean shear strength from start to finish of testing for each material. One product showed a significantly better mean shear strength than any other material at each test interval. The remaining materials were grouped in middle or low ranges, depending upon their final mean shear strengths and degrees of nonsignificance when compared to each other.
使用七种市售的直接粘结材料，将总共210个带有固位唇基底的双宽度不锈钢方丝弓托槽粘结到牛的切牙上。使用英斯特朗万能材料试验机对七种直接粘结材料中的每种材料的十个样本进行剪切强度测试。将样本在30%生理盐溶液中浸泡1天、1个月和3个月后进行测试。使用配对t检验，将每个时间间隔下每种直接粘结材料的平均剪切强度与每个时间间隔下每种材料的平均剪切强度进行统计学比较。使用相同的测试来确定每种材料从测试开始到结束时平均剪切强度是否有显著变化。在每个测试间隔中，有一种产品的平均剪切强度明显优于任何其他材料。其余材料根据其最终平均剪切强度以及相互比较时的不显著程度分为中等或低范围。
