Michalakis Konstantinos X, Calvani Pasquale Lino, Muftu Sinan, Pissiotis Argiris, Hirayama Hiroshi
1 Division of Graduate and Postgraduate Prosthodontics, Tufts University School of Dental Medicine, Boston, Mass.
J Oral Implantol. 2014 Apr;40(2):146-52. doi: 10.1563/AAID-JOI-D-11-00032.
Dental implants with an internal connection have been designed to establish a better stress distribution when lateral external forces act on the prosthesis and minimize the forces transmitted to the fastening screw. In the present study, 10 externally and 10 internally hexed implants were tested with a compressive force applied with an Instron Universal machine. Four cycles of loading-unloading were applied to each specimen to achieve displacements of 0.5, 1, 2, and 2.5 mm. The mean loads for the first cycle were 256.70 N for the external connection and 256 N for the internal connection implants. The independent t test did not reveal any significant differences among the 2 tested groups (P = .780). For the second cycle, the mean loads needed for a displacement of 1 mm were 818.19 N and 780.20 N for the external connection and the internal connection implants, respectively. The independent t test revealed significant differences among the 2 tested groups (P < .001). In the third cycle, the mean load values for a 2-mm displacement were 1394.10 N and 1225.00 N. The independent t test revealed significant differences among the 2 tested groups (P < .001). The mean loads for the fourth cycle were 1488.00 N for the external connection and 1029.00 N for the internal connection implants. These loads were required for a displacement of 2.5 mm. The independent t test revealed significant differences among the 2 tested groups (P < .001). The results of this in vitro study suggest that the internal connection design of the examined implant system could not prevent screw loosening during overloading. No implant or prosthesis failure was noticed in either group.
具有内部连接的牙种植体旨在当侧向外力作用于假体时建立更好的应力分布，并使传递到紧固螺钉的力最小化。在本研究中，使用英斯特朗万能材料试验机对10个外六角和10个内六角种植体施加压缩力进行测试。对每个样本施加四个加载-卸载循环，以实现0.5、1、2和2.5毫米的位移。外部连接种植体在第一个循环中的平均载荷为256.70牛，内部连接种植体为256牛。独立t检验未显示两个测试组之间有任何显著差异（P = 0.780）。在第二个循环中，外部连接和内部连接种植体实现1毫米位移所需的平均载荷分别为818.19牛和780.20牛。独立t检验显示两个测试组之间存在显著差异（P < 0.001）。在第三个循环中，2毫米位移的平均载荷值分别为1394.10牛和1225.00牛。独立t检验显示两个测试组之间存在显著差异（P < 0.001）。第四个循环中外部连接种植体的平均载荷为1488.00牛，内部连接种植体为1029.00牛。这些载荷是实现2.5毫米位移所需的。独立t检验显示两个测试组之间存在显著差异（P < 0.001）。这项体外研究的结果表明，所检查的种植体系统的内部连接设计在过载期间无法防止螺钉松动。两组均未发现种植体或假体失败。
