Estelita Sérgio, Janson Guilherme, Chiqueto Kelly, Janson Marcos, de Freitas Marcos Roberto
Department of Orthodontics, Bauru Dental School, University of São Paulo, Bauru, SP, Brazil.
Am J Orthod Dentofacial Orthop. 2009 Nov;136(5):722-35. doi: 10.1016/j.ajodo.2007.12.028.
Mini-implants are placed in restricted sites, requiring an accurate surgical technique. However, no systematic study has quantified technique accuracy to reliably predict the surgical risks. Therefore, a graduated 3-dimensional radiographic-surgical guide (G-RSG) was proposed, and its inaccuracy and risk index (RI) were estimated.
The sample consisted of 6 subjects (4 male, 2 female), who used mini-implant anchorage. Ten drill-free screws (DFS) were placed by using the G-RSG. The central point of the mesiodistal septum width (SW) was the selected implant site on the presurgical radiograph. The distances between DFS and the adjacent teeth (5-DFS and 6-DFS) were measured to evaluate screw centralization and inaccuracy degree (ID). These distances were statistically compared by independent t tests, and inaccuracy was determined by the expression ID = (5-DFS - 6-DFS)/2, which represents deviation of the mini-implant's final position regarding the central point initially selected. Then SW, ID, and screw diameter (SØ) were combined to estimate the surgical risk with RI expressed by RI = SØ/SW - ID.
The 5-DFS and 6-DFS distances were not significantly different. The ID of the G-RSG was 0.17 mm. The low ID ensured a safe RI (<1) in spite of the restricted SW.
The G-RSG accuracy allowed fine prediction of the final DFS position in the interradicular septum, with a low RI, which is a helpful tool to estimate surgical risks.
微型种植体植入部位受限，需要精确的手术技术。然而，尚无系统研究对技术准确性进行量化以可靠预测手术风险。因此，提出了一种分级三维放射外科手术导板（G-RSG），并对其不准确性和风险指数（RI）进行了评估。
样本包括6名使用微型种植体支抗的受试者（4名男性，2名女性）。使用G-RSG植入10枚无钻螺钉（DFS）。术前X光片上近远中牙槽间隔宽度（SW）的中心点为选定的种植体植入部位。测量DFS与相邻牙齿之间的距离（5-DFS和6-DFS）以评估螺钉的中心化程度和不准确度（ID）。通过独立t检验对这些距离进行统计学比较，并通过ID =（5-DFS - 6-DFS）/2来确定不准确性，该表达式表示微型种植体最终位置相对于最初选定中心点的偏差。然后将SW、ID和螺钉直径（SØ）相结合来评估手术风险，RI表示为RI = SØ/SW - ID。
5-DFS和6-DFS距离无显著差异。G-RSG的ID为0.17毫米。尽管SW受限，但低ID确保了安全的RI（<1）。
G-RSG的准确性能够精确预测根间间隔内DFS的最终位置，RI较低，是评估手术风险的有用工具。
