Abstract：
The present study aimed to evaluate the degree of nerve injury on inferior alveolar nerve (IAN) by different implant drills resulting from direct canal intrusion into inferior alveolar canal (IAC). A cadaveric study involving 7 human mandibles was performed to evaluate mechanical injury of canal enclosed IAN resulting from different drills. In group 1, osteotomies were created using different drills with 1 mm of intracanal intrusion, simulating accidental drill intrusion into canal. In group 2, drilling was stopped when the tip has breached into IAC, limited by tactile feedback of operator. The depth and width of nerve defects were assessed using optical coherence tomography. A significant difference in defect depth was found (p < 0.001) in group 1. A sinus lift reamer inflicted the least damage (0.068 ± 0.022 mm). It was also found that the mean defect depth was significantly different when a twist drill was used (p = 0.016). Sinus lift reamer can be used safely for osteotomy preparation in mandible when bone height is limited or when radiographic visualization of canal is poor. Bone corticalization around IAC does not provide adequate protection for IAN in the event of accidental intracanal intrusion.
摘要：
本研究旨在评估由于直接进入下牙槽管（IAC）而导致的不同植入物钻头对下牙槽神经（IAN）的神经损伤程度。进行了一项涉及7个人下颌骨的尸体研究，以评估由于不同的钻头而导致的运河封闭IAN的机械损伤。在第1组中，使用不同的钻头进行截骨术，肛门内侵入1mm，模拟意外钻进运河。在第2组中，当尖端突破IAC时停止钻孔，受操作者触觉反馈的限制。使用光学相干断层扫描评估神经缺损的深度和宽度。在第1组中发现缺损深度的显著差异(p<0.001)。鼻窦提升铰刀造成的损伤最小(0.068±0.022mm)。还发现，当使用麻花钻时，平均缺陷深度显着不同（p=0.016）。当骨骼高度有限或放射学对下颌骨的可视化较差时，可以安全地使用窦抬举扩孔钻进行下颌骨截骨准备。IAC周围的骨皮质化在意外肛门内侵入的情况下不能为IAN提供足够的保护。
