Olin P S
Division of Prosthodontics, University of Minnesota, School of Dentistry, Minneapolis.
J Prosthet Dent. 1990 Nov;64(5):563-5. doi: 10.1016/0022-3913(90)90128-y.
Occasionally the need arises to remove restorations that have been cemented. Several ultrasonic tips have been developed to aid in removing cemented restorations. Earlier studies of the effects of ultrasonic vibration reveal detrimental effects on amalgam surface and marginal integrity and, at short instrumentation periods (2.5 minutes) in vitro, no significant effect on the retention of cemented cast crowns. Twenty identically machined metal dies had nonprecious crowns waxed, cast, and fitted. Each casting was cemented twice with glass ionomer and zinc phosphate cement. Each cement was tested for the effects of vibration on retention. The cements were mixed according to manufacturer's specifications, placed under 5 kg load, then placed in 37 degrees C water and contained in a humidor. Retention was tested with a 4202 Instron machine to determine the forces needed to overcome retention. Retention ranged from a high of 125.36 kg for glass ionomer without vibration to a low of 19.11 kg for zinc phosphate vibrated for 12 minutes. The use of vibration is considered an advantageous adjunct to other cast restoration removal devices.
偶尔会出现需要去除已粘固修复体的情况。已经开发了几种超声探头来辅助去除粘固的修复体。早期关于超声振动影响的研究表明，超声振动对汞合金表面和边缘完整性有不利影响，并且在体外短时间（2.5分钟）操作时，对粘固铸造冠的固位没有显著影响。二十个相同加工的金属代型制作了非贵金属冠，进行蜡型制作、铸造和试戴。每个铸件用玻璃离子水门汀和磷酸锌水门汀各粘固两次。测试每种水门汀振动对固位力的影响。水门汀按照制造商的规格混合，施加5千克负荷，然后置于37摄氏度的水中，并放在保湿器中。用4202型英斯特朗材料试验机测试固位力，以确定克服固位所需的力。固位力范围从无振动时玻璃离子水门汀的125.36千克到振动12分钟的磷酸锌水门汀的19.11千克不等。振动的使用被认为是其他铸造修复体去除装置的有利辅助手段。
