Kim Gyu-Tae, Kim Seong-Hun, Choi Yong-Suk, Park Young-Joon, Chung Kyu-Rhim, Suk Kyung-Eun, Choo HyeRan, Huang John C
Department of Oral and Maxillofacial Radiology, School of Dentistry, KyungHee University, Seoul, Korea.
Am J Orthod Dentofacial Orthop. 2009 Nov;136(5):628.e1-10; discussion 628-9. doi: 10.1016/j.ajodo.2009.02.023.
The purposes of this study were to evaluate the actual postplacement positions of orthodontic miniplate anchoring screws (MPAS) and to determine the risk factors for their failure and iatrogenic effects on the intraoral structures.
Three-dimensional cone-beam computed tomography images were generated to examine 31 orthodontic miniplates and their MPAS (diameter, 1.5 mm; length, 4 mm), which showed good clinical stability 6 months after placement in the posterior maxilla of 18 patients. The cone-beam computed tomography data were analyzed with analysis of variance (ANOVA) statistics to evaluate the difference of placement depth and vertical distance of the MPAS from the cementoenamel junction to the center of the screw. The Fisher exact test was used to determine differences in MPAS position, root proximity, and sinus penetration.
The mean placement depth of the MPAS was 2.48 mm with no significant difference relative to their position. Twenty-six (of 74) MPAS were placed in the dentition area. Of these 26, 14 were placed in interdental spaces, and the other 12 followed the direction of the roots. Nine MPAS showed root proximity, and 7 MPAS had root penetration, all of which were placed in the central position of the miniplate. Thirty-nine MPAS penetrated the sinus, indicating a low interrelationship between placement depth and cortical bone thickness of the sinus.
Miniplates were successfully retained by MPAS even with less-than-ideal placement. Root contact and proximity of MPAS seem to have minimal effects on the successful stabilization of miniplates. Pertinent guidelines should, however, be followed during MPAS placement to minimize the risk of damage to adjacent roots.
本研究的目的是评估正畸微型钢板锚固螺钉（MPAS）植入后的实际位置，并确定其失败的风险因素以及对口腔内结构的医源性影响。
生成三维锥形束计算机断层扫描图像，以检查31个正畸微型钢板及其MPAS（直径1.5毫米；长度4毫米），这些微型钢板在18例患者上颌后部植入6个月后显示出良好的临床稳定性。使用方差分析（ANOVA）统计方法分析锥形束计算机断层扫描数据，以评估MPAS从牙骨质釉质界到螺钉中心的植入深度和垂直距离的差异。采用Fisher精确检验确定MPAS位置、与牙根的接近程度和窦腔穿透情况的差异。
MPAS的平均植入深度为2.48毫米，相对于其位置无显著差异。74个MPAS中有26个位于牙列区域。在这26个中，14个位于牙间隙，另外12个沿牙根方向。9个MPAS显示与牙根接近，7个MPAS有牙根穿透，所有这些均位于微型钢板的中心位置。39个MPAS穿透窦腔，表明植入深度与窦腔皮质骨厚度之间的相关性较低。
即使植入位置不理想，微型钢板也能通过MPAS成功固定。MPAS与牙根的接触和接近似乎对微型钢板的成功稳定影响最小。然而，在植入MPAS时应遵循相关指南，以尽量减少对相邻牙根造成损伤的风险。
