Department of Orthodontics, Kyungpook National University, Daegu, Korea.
Am J Orthod Dentofacial Orthop. 2010 Feb;137(2):200-6. doi: 10.1016/j.ajodo.2008.04.028.
To provide information about placement sites and angulations of microimplants between tooth roots, we analyzed 3-dimensional computed tomography images from 25 patients.
The patients in the sample had good interdigitation, no restorations, and no arch length discrepancies in the posterior segments. Three-dimensional images of the maxillary and mandibular second premolars, first molars, and second molars were constructed. The distances and midpoints between the roots at 3 levels were calculated, and the angles between the lines connecting the midpoints and perpendicular lines to the occlusal plane at the contact points were also calculated.
The midpoints between the roots were located distally to the contact point and from the cervical to the apical areas. The lines connecting these midpoints from the cervix to the apex of the roots in the mandibular arch had more distal inclination than in the maxillary arch.
To minimize root contacts, microimplants need to be inclined distally about 10 degrees to 20 degrees and placed 0.5 to 2.7 mm distally to the contact point to minimize root contact according to sites and levels, except into palatal interradicular bone between the maxillary first and second molars.
为了提供有关牙根间微种植体放置位置和角度的信息，我们分析了 25 名患者的三维计算机断层扫描图像。
样本中的患者具有良好的交错度，后段无修复体，也无弓长差异。构建了上颌和下颌第二前磨牙、第一磨牙和第二磨牙的三维图像。计算了 3 个水平的牙根之间的距离和中点，并计算了连接中点和接触点处与咬合平面垂直的线之间的角度。
根尖中点位于接触点的远中侧，从颈到根尖区域。从颈到根尖连接这些中点的线在下颌弓中的倾斜度比在上颌弓中更远。
为了最小化根接触，微种植体需要向远中倾斜约 10 度至 20 度，并根据位置和水平放置在接触点远中 0.5 至 2.7 毫米处，以最小化根接触，除了上颌第一和第二磨牙之间的腭根间骨。
