Marshall T D, Cooley R L
Am J Dent. 1989 Dec;2(6):349-53.
This study evaluated the Max 017 retentive pin (.019 in./.48 mm) and its twist drill (.017 in./.43 mm) along with the Max 021 pin (.024 in., .61 mm) and its twist drill (.021 in./.53 mm), in relation to shoulder stop position, space between the end of the pin and the end of the channel and the development of cracks in dentin adjacent to pin channels. A total of 20 non-carious human molar teeth were used, 10 for each size pin. Four pins were placed in each tooth for a total of 40 of each size pin. An air turbine contra-angle was used at 1,200 rpm to prepare all channels and seat all pins. Results showed that with the 017 pins, only 14 pins out of 40 (35%) were completely seated with the shoulder stop against dentin, while the 021 pins had 36 out of 38 (95%) of the shoulder stops completely seated. There was a significant difference in the two groups. Cracks were seen adjacent to only one pin. Space between the end of the pin and the end of the channel for the 017 pins whose shoulder stops were seated was an average of .55 mm, while the 021 pins had an average of .14 mm.
本研究评估了Max 017固位钉（0.019英寸/0.48毫米）及其麻花钻（0.017英寸/0.43毫米），以及Max 021固位钉（0.024英寸/0.61毫米）及其麻花钻（0.021英寸/0.53毫米）在肩部止动位置、钉末端与根管末端之间的间隙以及钉道相邻牙本质中裂纹形成方面的情况。总共使用了20颗无龋的人类磨牙，每种尺寸的固位钉各用10颗。每颗牙齿放置4颗固位钉，每种尺寸的固位钉共放置40颗。使用转速为1200转/分钟的气动涡轮反角手机制备所有根管并就位所有固位钉。结果显示，对于017固位钉，40颗中只有14颗（35%）的肩部止动完全抵靠牙本质就位，而021固位钉的38颗中有36颗（95%）的肩部止动完全就位。两组之间存在显著差异。仅在一颗固位钉附近观察到裂纹。肩部止动就位的017固位钉的钉末端与根管末端之间的间隙平均为0.55毫米，而021固位钉的平均间隙为0.14毫米。
