Istanbul University, Faculty of Dentistry, Department of Oral and Maxillofacial Surgery, Istanbul Turkey.
Int J Med Sci. 2018 Sep 11;15(13):1466-1471. doi: 10.7150/ijms.26697. eCollection 2018.
Malfixed miniplates can impair fracture healing, and the screw pilot holes may widen during repeated fixation trials. This study explored the extent to which screw fixation of mandibular angle fractures could be improved by augmenting the drilling holes with polymethylmethacrylate (PMMA). We measured stabilization by recording specimen displacement under a vertical force of 50 N applied using a hydraulic tester. We included 20 hemimandibles from sheep (average weight 40 kg). The specimens were randomly divided into two groups of 10 and pilot holes were created in the angulus region using a drill 1.2 mm in diameter. Next, we performed osteotomies simulating angulus fracture repair. In group 1, the fracture site was fixed using non-compression miniplates and four screws were inserted to the maximal possible extent employing a mechanical screwdriver. In group 2, the pilot drill holes were filled with PMMA prior to miniplate fixation. Then vertical forces of 50 N were applied to the molar region and the displacements were measured. The Shapiro-Wilks test was used to compare the two groups. The maximum average displacement in the experimental group was significantly lower than that in the control group (p=0.026). Thus, PMMA-augmented screws better stabilized bone, affording reliable fixation.
固定不当的小型接骨板可能会影响骨折愈合，并且在反复固定试验中，螺钉导孔可能会变宽。本研究探讨了通过聚甲基丙烯酸甲酯（PMMA）增强钻孔来改善下颌角骨折螺钉固定的程度。我们通过使用液压试验机施加 50N 的垂直力来记录标本的位移来测量稳定性。我们纳入了 20 个来自绵羊的半下颌骨（平均体重 40 公斤）。标本随机分为两组，每组 10 个，使用直径 1.2 毫米的钻头在下颌角区域创建导孔。接下来，我们进行了模拟下颌角骨折修复的截骨术。在第 1 组中，使用非加压小型接骨板固定骨折部位，并使用机械螺丝刀尽可能地插入 4 个螺钉。在第 2 组中，在小型接骨板固定之前，将导孔填充 PMMA。然后，在磨牙区域施加 50N 的垂直力，并测量位移。使用 Shapiro-Wilks 检验比较两组。实验组的最大平均位移明显低于对照组（p=0.026）。因此，PMMA 增强的螺钉更好地稳定了骨骼，提供了可靠的固定。
