Goto Takaharu, Nagao Kan, Ishida Yuichi, Tomotake Yoritoki, Ichikawa Tetsuo
Department of Oral & Maxillofacial Prosthodontics and Oral Implantology, The University of Tokushima, Institute of Health Biosciences, Tokushima, Japan.
J Prosthodont. 2015 Feb;24(2):156-63. doi: 10.1111/jopr.12177. Epub 2014 Jun 27.
This in vitro study investigated the effect of attachment installation conditions on the load transfer and denture movements of implant overdentures, and aims to clarify the differences among the three types of attachments, namely ball, Locator, and magnet attachments.
Three types of attachments, namely ball, Locator, and magnetic attachments were used. An acrylic resin mandibular edentulous model with two implants placed in the bilateral canine regions and removable overdenture were prepared. The two implants and bilateral molar ridges were connected to three-axis load-cell transducers, and a universal testing machine was used to apply a 50 N vertical force to each site of the occlusal table in the first molar region. The denture movement was measured using a G(2) motion sensor. Three installation conditions, namely, the application of 0, 50, and 100 N loads were used to install each attachment on the denture base. The load transfer and denture movement were then evaluated.
The resultant force decreased with increasing installation load for all attachments. In particular, the resultant force on implants on the loading side of the Locator attachment significantly decreased when the installation load was increased from 0 to 50 N, and that for magnetic attachment significantly decreased when the installation load was increased from 50 to 100 N. For the residual ridges on the loading side, the direction of the forces for all attachments changed to downward with increasing installation load. Furthermore, the yaw Euler angle increased with increasing installation load for the magnetic attachment.
Subject to the limitations of this study, the use of any installation load greater than 0 N is recommended for the installation of ball and Locator attachments on a denture base. Regarding magnetic attachments, our results also recommend installation on a denture base using any installation load greater than 0 N, and suggest that the resultant force acting on the implant can be decreased by increasing the installation load; however, a large installation load of 100 N should be avoided when installing the attachment on the denture base to avoid increasing the denture movement.
本体外研究调查了附着体安装条件对种植覆盖义齿的负荷传递和义齿运动的影响，旨在阐明三种类型的附着体，即球帽式、Locator和磁性附着体之间的差异。
使用了三种类型的附着体，即球帽式、Locator和磁性附着体。制备了一个丙烯酸树脂下颌无牙颌模型，在双侧尖牙区植入两颗种植体，并制作了可摘覆盖义齿。将两颗种植体和双侧磨牙嵴连接到三轴测力传感器上，并使用万能试验机在第一磨牙区的咬合面各部位施加50 N的垂直力。使用G(2)运动传感器测量义齿运动。三种安装条件，即施加0、50和100 N的负荷，用于将每个附着体安装在义齿基托上。然后评估负荷传递和义齿运动。
所有附着体的合力均随安装负荷的增加而降低。特别是，当Locator附着体的安装负荷从0 N增加到50 N时，加载侧种植体上的合力显著降低；当磁性附着体的安装负荷从50 N增加到100 N时，合力显著降低。对于加载侧的剩余牙槽嵴，所有附着体的力的方向随着安装负荷的增加而变为向下。此外，磁性附着体的偏航欧拉角随安装负荷的增加而增加。
受本研究的限制，建议在义齿基托上安装球帽式和Locator附着体时使用大于0 N的任何安装负荷。对于磁性附着体，我们的结果也建议在义齿基托上使用大于0 N的任何安装负荷进行安装，并表明通过增加安装负荷可以降低作用在种植体上的合力；然而，在义齿基托上安装附着体时应避免100 N的大安装负荷，以避免增加义齿运动。
