Cameron S M, Joyce A, Brousseau J S, Parker M H
Maxillofacial Prosthetics/Dental Oncology, U.S. Army Dental Activity, Fort Gordon, Ga., USA.
J Prosthet Dent. 1998 Mar;79(3):298-303. doi: 10.1016/s0022-3913(98)70241-0.
It is possible to incorrectly seat an abutment on an external hex implant.
This study investigated the theoretical and practical limits of radiographic verification of the complete seating of implant abutments on external hex implants.
A positioning device that could accurately place the film and/or tube head in any vertical relation desired relative to the implant and abutment was fabricated. For all records, a standard abutment was secured to the implant in both a fully seated position (closed) and with the abutment turned approximately 30 degrees and seated atop the implant external hex (open). Digital radiographs were made with the tube head fixed perpendicular to the implant and the film angled at 0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 degrees. The film was then positioned parallel to the implant and the tube head was angled at 0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 degrees. An image of each position was shown to 36 dentists and they were asked if the image was diagnostic for determining the status of the implant/abutment interface.
The data were analyzed with a computer statistics program. The group with the tube head changed was analyzed with the Cochran's Q test and revealed a statistically significant (p < 0.0001) change in the diagnostic value of radiographs beginning at 20 degrees. The group with the film angle changed was analyzed with a Pearson chi-square and showed no statistical difference (p = 0.394) for the diagnostic value of any of the film angles.
Maintaining the tube head to less than 20 degrees from perpendicular to the long axis of the implant resulted in a diagnostic radiograph, regardless of the angle of the film.
外部六角形种植体上的基台可能未正确就位。
本研究调查了通过影像学检查验证外部六角形种植体上种植体基台完全就位的理论和实际限度。
制作了一种定位装置，该装置可将胶片和/或管头相对于种植体和基台精确放置在任何所需的垂直关系中。对于所有记录，将一个标准基台以完全就位位置（闭合）固定在种植体上，并将基台旋转约30度后放置在种植体外部六角形顶部（打开）。管头垂直于种植体固定，胶片倾斜0、5、10、15、20、25、30、35、40和45度拍摄数字化X线片。然后将胶片平行于种植体放置，管头倾斜0、5、10、15、20、25、30、35、40和45度。将每个位置的图像展示给36名牙医，并询问他们该图像是否有助于判断种植体/基台界面的状态。
使用计算机统计程序对数据进行分析。对管头位置改变的组采用 Cochr an Q检验进行分析，结果显示从20度开始，X线片的诊断价值有统计学显著变化（p < 0.0001）。对胶片角度改变的组采用Pearson卡方检验进行分析，结果显示任何胶片角度的诊断价值均无统计学差异（p = 0.394）。
管头与种植体长轴垂直方向的夹角保持在小于20度时，无论胶片角度如何，均可获得具有诊断价值的X线片。
