ObjectiveTo assess the relative position of mini‐implants to retain a mandibular overdenture, according to the surgical protocol, technical and anatomical factors.MethodsMandibular cone‐beam computed tomography (CBCT) scans were analyzed for 73 patients who received four one‐piece titanium‐zirconium mini‐implants. Drilling was performed using a 1.6 mm needle drill and a 2.2 mm Pilot Drill, according to the bone density with a surgical stent. Post‐insertion CBCT images in DICOM format were analyzed using the E‐Vol‐DX software with BAR filters. Divergence angle between implants and between implants and the overdenture path of insertion was measured using CliniView 10.2.6 software.ResultsDivergence between implants ranged from 0° to 22.3° (mean = 4.2; SD = 3.7) in the lateral and from 0° to 26.2° (mean = 5.3; SD = 4.1) in the frontal projections (p < .001). Only 1 (0.2%) and 3 (0.7%) of the measurements were higher than 20° in the lateral and frontal views, respectively. The mean angulations between the implant and the path of insertion for the overdenture were 9.3° (SD = 7.5) and 4.0° (SD = 2.9) for the lateral and frontal views, respectively (p < .001). Regression analyses showed a significant association between the divergence of implants and the frontal view projection (p < .001), greater distance between the paired implants (p = .017), the flapped surgical protocol (p = .002), higher final insertion torque (p = .011), and deeper preparation with the needle drill (p < .001).ConclusionsThe mini‐implants were placed with low divergence angles and satisfactory parallelism. Factors including shorter distances between the implants, higher density bone, and a flapless surgical approach all contributed positively to improved parallelism of the mini‐implants.

中文翻译：

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使用非引导手术对用于下颌覆盖义齿的一体式钛-锆微型种植体的相对位置进行横断面 CBCT 评估


目的根据手术方案、技术和解剖因素评估微型种植体保留下颌覆盖义齿的相对位置。方法对 73 例接受 4 例一体式钛-锆微型植入物的患者进行下颌锥束计算机断层扫描 （CBCT） 扫描分析。根据手术支架的骨密度，使用 1.6 mm 针钻和 2.2 mm Pilot Drill 进行钻孔。使用带有 BAR 过滤器的 E-Vol-DX 软件分析 DICOM 格式的插入后 CBCT 图像。使用 CliniView 10.2.6 软件测量种植体之间以及种植体之间的发散角和覆盖义齿的插入路径。结果种植体之间的差异范围为 0° 至 22.3°（平均值 = 4.2;SD = 3.7） 在侧位和 0° 到 26.2° （平均值 = 5.3;SD = 4.1） 在额叶突起 （p < .001） 中。只有 1 个 （0.2%） 和 3 个 （0.7%） 的测量值分别在侧视图和正面视图中高于 20°。侧位和正面视图的种植体与覆盖义齿插入路径之间的平均角度分别为 9.3° （SD = 7.5） 和 4.0° （SD = 2.9） （p < .001）。回归分析显示，植入物的发散与正面投影 （p < .001）、成对植入物之间的距离更大 （p = .017）、翻瓣手术方案 （p = .002）、更高的最终插入扭矩 （p = .011） 以及使用针钻进行更深入的准备 （p < .001）。结论微型种植体的放置具有较低的发散角和令人满意的平行度。包括植入物之间更短的距离、更高密度的骨骼和无瓣手术方法在内的因素都对改善微型植入物的平行度做出了积极贡献。