Lee Hyeonjong, Kwon Kung-Rock, Paek Janghyun, Pae Ahran, Noh Kwantae
Int J Oral Maxillofac Implants. 2017 September/October;32(5):1018–1022. doi: 10.11607/jomi.5324. Epub 2017 May 18.
Rotational errors of implants can occur during two stages: when connecting impression copings with implants, and when connecting impression copings with analogs. The aim of this study was to determine ways to minimize these rotational errors.
Three types of implants were prepared: a tissue-level implant with an internal octagon 8-degree Morse taper connection, a bone-level implant with an internal hex 11-degree Morse taper connection, and a bone-level implant with an external hex connection. Each complex (n = 10 per group) was composed of an implant, an impression coping, and an analog. Implants were embedded in resin blocks and connected with corresponding impression copings. Analogs that reproduced the position of the implants were created by means of a custom-made transfer jig, and rotational errors were measured between implants and analogs. Impression copings and analogs were connected by means of four methods: The impression coping was connected to the implant in a clockwise (CW) or a counterclockwise (CCW) direction before tightening, and the analogs were then connected with impression copings and tightened using a hemostat (Hs) or by hand (Hd).
The CW-Hs and CCW-Hd groups exhibited low rotational error (mean ± standard deviation 0.11 ± 0.21 and 0.19 ± 0.34 degrees, respectively), whereas the CW-Hd and CCW-Hs groups exhibited high rotational error (-1.80 ± 0.67 and 2.07 ± 0.75, respectively) in different directions. A strong association was observed between the tightening method and rotational error, and a weak association was observed between the connection type and rotational error.
The CW-Hs method was found to be the most suitable for minimizing rotational error between implants and analogs.
种植体的旋转误差可能在两个阶段出现：将印模帽与种植体连接时，以及将印模帽与代型连接时。本研究的目的是确定将这些旋转误差降至最低的方法。
制备三种类型的种植体：一种具有内部八角形8度莫氏锥度连接的软组织水平种植体、一种具有内部六边形11度莫氏锥度连接的骨水平种植体和一种具有外部六边形连接的骨水平种植体。每组（每组n = 10）的复合体均由一个种植体、一个印模帽和一个代型组成。将种植体嵌入树脂块中，并与相应的印模帽连接。通过定制的转移夹具制作再现种植体位置的代型，并测量种植体与代型之间的旋转误差。印模帽和代型通过四种方法连接：在拧紧之前，将印模帽以顺时针（CW）或逆时针（CCW）方向连接到种植体，然后使用止血钳（Hs）或手动（Hd）将代型与印模帽连接并拧紧。
顺时针-止血钳组和逆时针-手动组表现出较低的旋转误差（分别为平均±标准差0.11±0.21度和0.19±0.34度），而顺时针-手动组和逆时针-止血钳组在不同方向上表现出较高的旋转误差（分别为-1.80±0.67度和2.07±0.75度）。在拧紧方法与旋转误差之间观察到强关联，在连接类型与旋转误差之间观察到弱关联。
发现顺时针-止血钳方法最适合将种植体与代型之间的旋转误差降至最低。
