Wilson P R, Goodkind R J, Delong R, Sakaguchi R
University of Minnesota, School of Dentistry, Minneapolis.
J Prosthet Dent. 1990 Nov;64(5):601-9. doi: 10.1016/0022-3913(90)90136-z.
Deformation of crowns during cementation was investigated by a simple loading system of defined crowns with silicone fluids as cements. Deformation of the crowns was measured by long stain gauges that encircled the cervical margins. Die spacing was simulated by etching the die. Venting was simulated by removing a small screw. Deformation of the crowns was decreased by decreasing the viscosity of fluid, increasing the thickness of the crowns, and venting. Etching the die decreased the seating times of the crowns, but did not alter the level of deformation. Terminal cementation with zinc phosphate cement confirmed the presence of crown deformation during cementation. The results have consequences for bonded and all-ceramic crowns, and explain several clinical phenomena. It is suggested that low viscosity cements, low seating forces, and die spacing be used to decrease the deformation of crowns during seating. The importance of passive fitting of the crown to the tooth is stressed.
通过使用以硅酮流体作为粘结剂的特定牙冠简单加载系统，研究了粘结过程中牙冠的变形情况。牙冠的变形通过环绕颈部边缘的长应变片进行测量。通过蚀刻模型来模拟模型间距。通过移除一个小螺丝来模拟排气。通过降低流体粘度、增加牙冠厚度和排气，牙冠的变形得以减少。蚀刻模型减少了牙冠的就位时间，但并未改变变形程度。用磷酸锌水门汀进行最终粘结证实了粘结过程中牙冠变形的存在。这些结果对粘结式和全瓷牙冠有影响，并解释了一些临床现象。建议使用低粘度粘结剂、低就位力和模型间距来减少就位过程中牙冠的变形。强调了牙冠与牙齿被动贴合的重要性。
