Schulte G A, Hermesch C B, Vandewalle K S, Buikema D J
Dunn Dental Clinic, Department of General Dentistry, Lackland AFB, TX 78236-5551, USA.
Oper Dent. 1998 Mar-Apr;23(3):108-12.
Amalgapins are susceptible to early fracture during matrix removal and carving. The purpose of this study was to examine the early fracture resistance of amalgapin-retained restorations using a spherical amalgam alloy, an admixed amalgam alloy, a combination of admixed alloy over the spherical alloy, and a recently introduced modified spherical amalgam alloy. Four amalgapin channels with a diameter of 1.4 mm and depth of 2 mm were prepared in cylinders of Macor, a machinable ceramic material. The amalgapins were hand condensed, and the bulk of the restoration was mechanically condensed. In the group using the combination of alloys, 800 mg of spherical alloy was condensed into the amalgapins and over the floor of the preparation. The admixed alloy was then condensed over the spherical alloy to build up the bulk of the restoration. Using an Instron Universal Testing Machine, the restorations were tested to shear failure at an average of 15.8 +/- 1.3 minutes after the initiation of trituration of the amalgam alloy. A metal ring was placed around the restoration and pulled 90 degrees to the long axis to simulate matrix band removal. Data were analyzed using Kruskal-Wallis procedures. The fracture resistance of the spherical alloy group and the spherical/admixed group were significantly higher than admixed or Tytin FC. All fractures occurred in amalgam at the entrance to the amalgapin channel. The combination of spherical and admixed amalgam alloys in a restoration may reduce the potential for early dislodgment while allowing additional time for carving.
银汞桩在去除基质和雕刻过程中容易早期折断。本研究的目的是使用球形银汞合金、混合型银汞合金、在球形合金上覆盖混合型合金以及一种最近推出的改良球形银汞合金，来检测银汞桩固位修复体的早期抗折性。在可加工陶瓷材料Macor圆柱体中制备4个直径1.4mm、深度2mm的银汞桩通道。银汞桩采用手工压实，修复体的主体采用机械压实。在使用合金组合的组中，将800mg球形合金压实到银汞桩中以及制备窝洞底部。然后将混合型合金压实到球形合金上以构建修复体主体。使用英斯特朗万能试验机，在银汞合金研磨开始后平均15.8±1.3分钟对修复体进行剪切破坏测试。在修复体周围放置一个金属环，并向与长轴成90度的方向拉动以模拟去除成形片环。使用Kruskal-Wallis程序分析数据。球形合金组和球形/混合型组的抗折性显著高于混合型组或Tytin FC组。所有折断均发生在银汞桩通道入口处的银汞合金中。在修复体中使用球形和混合型银汞合金的组合可能会降低早期脱位的可能性，同时为雕刻留出更多时间。
