Gumber Tejinder Kaur, Kandiara Parveen, Bhullar Ramandeep Singh, Dhawan Amit, Kapila Sarika, Singh Balwinder
Department of Oral and Maxillofacial Surgery, Sri Guru Ram Das Institute of Dental Sciences and Research, Amritsar, India.
Department of Oral Medicine and Radiology, Sri Guru Ram Das Institute of Dental Sciences and Research, Amritsar, India.
J Maxillofac Oral Surg. 2023 Sep;22(3):590-602. doi: 10.1007/s12663-022-01835-x. Epub 2022 Dec 28.
The extraction of impacted mandibular third molar is associated with various types of intraoperative and postoperative complications, one of them is injury to lingual nerve. The present study aims to assess and correlate the variation in lingual cortical plate thickness with different angulations and determine the topographic relationship between the root apex of impacted mandibular third molar and lingual cortical plate using Cone Beam Computed Tomography (CBCT).
This prospective cohort study enrolled 140 patients with impacted mandibular third molars who underwent preoperative CBCT imaging. The CBCT images were used to evaluate the outcome variables such as lingual cortical plate thickness and topographical relationship between root apex of impacted mandibular third molar and lingual cortical plate. The predictor variables included age, gender, inclination of third molar, mesiodistal angle, buccolingual angle and lingual plate morphology.
The temporary lingual nerve paresthesia was reported by 1 patient (0.71%) out of 140 patients. The lingual bone in distoangular and vertical impacted third molar was found to be 1.20 times thicker than mesioangular and horizontal teeth. Lingual bone thinning at mid-root level was observed in maximum number of cases with mesioangular teeth (68.5%), whereas horizontal impacted teeth showed lingual bone thinning (90.9%) at root apex level. The mean buccolingual angle of impacted mandibular third molar was found to be significantly associated with lingual bone perforation ( value = 0.0258). The morphology of lingual plate was observed as undercut type (37.14%) followed by slanted (36.43%), parallel (19.29%) and round type (7.14%).
Increase in buccolingual angle of impacted mandibular third molar decreases lingual bone thickness which is the natural barrier for protecting injury to lingual nerve. Also undercut and slanted lingual plate shapes were recognised as risk factors for contact/perforation between root apex and lingual plate. Therefore, proper screening and planning of high risk patients before third molar extraction is crucial.
下颌阻生第三磨牙拔除术会引发多种术中及术后并发症，其中之一是舌神经损伤。本研究旨在利用锥形束计算机断层扫描（CBCT）评估舌侧皮质骨板厚度在不同角度下的变化并进行相关性分析，同时确定下颌阻生第三磨牙根尖与舌侧皮质骨板之间的地形关系。
这项前瞻性队列研究纳入了140例接受术前CBCT成像的下颌阻生第三磨牙患者。CBCT图像用于评估诸如舌侧皮质骨板厚度以及下颌阻生第三磨牙根尖与舌侧皮质骨板之间的地形关系等结果变量。预测变量包括年龄、性别、第三磨牙倾斜度、近远中角、颊舌角和舌板形态。
140例患者中有1例（0.71%）报告出现暂时性舌神经感觉异常。发现远中倾斜和垂直阻生第三磨牙的舌侧骨比近中倾斜和水平阻生牙厚1.20倍。近中倾斜牙在牙根中部水平舌侧骨变薄的病例最多（68.5%），而水平阻生牙在根尖水平舌侧骨变薄的比例为90.9%。发现下颌阻生第三磨牙的平均颊舌角与舌侧骨穿孔显著相关（值 = 0.0258）。观察到舌板形态为倒凹型（37.14%），其次是倾斜型（36.43%）、平行型（19.29%）和圆形（7.14%）。
下颌阻生第三磨牙颊舌角增大导致舌侧骨厚度减小，而舌侧骨是保护舌神经免受损伤的天然屏障。此外，倒凹型和倾斜型舌板形态被认为是根尖与舌板接触/穿孔的危险因素。因此，在第三磨牙拔除术前对高危患者进行适当筛查和规划至关重要。
