Mukherjee Subhadeep, Vikraman Bhaskarapandiyan, Sankar Duraiswamy, Veerabahu Muthu Subramanian
Ex - Post Graduate Student, Department of Oral and Maxillofacial Surgeon, Ragas Dental College and Hospital , Chennai, Tamilnadu, India .
Professor, Department of Oral and Maxillofacial Surgery, Ragas Dental College and Hospital , Chennai, Tamilnadu, India .
J Clin Diagn Res. 2016 Aug;10(8):ZC57-62. doi: 10.7860/JCDR/2016/20991.8273. Epub 2016 Aug 1.
Iatrogenic damage to Inferior Alveolar Nerve (IAN) is a significant risk factor following prophylactic or therapeutic removal of impacted mandibular third molar. The risk to IAN injury increases many fold, when the third molar root overlaps the nerve canal as identified by the radiographic imaging. Various methods like orthodontic assisted extraction, staged removal of tooth or coronectomy have been advocated to reduce the incidence of IAN injury in high risk cases with variable outcome.
The aim of present study was to evaluate the fate of the root (resorbed, exfoliated, covered by bone) after coronectomy or intentional root retention of impacted mandibular 3(rd) molars in patients with high risk for inferior alveolar nerve damage as evaluated by the intra oral periapical radiograph.
Twenty impacted mandibular third molar teeth, in 18 patients with high risk of injury to IAN based on Rood's Criteria in an intra oral periapical radiographic examination, between the age group of 18 to 40 years, were included in the study. Preoperatively the impacted third molars were evaluated clinically as well as radiographically. Pederson Difficulty Index and Winter's Classification of impacted tooth was recorded. Coronectomy was done at the cemento enamel junction leaving the roots 2-3mm below the alveolar crest and primary closure was done. Patients were evaluated periodically for two years at six months interval. Post operative pain, swelling, IAN injury or any other complications were observed and recorded.
None of the patients had IAN injury and none required second surgical removal. There was no incidence of post-operative infection and none required second surgical intervention. However, two of our patients had failed coronectomy (10%) due to mobilization of roots intra operatively and the roots were removed. One patient developed profuse bleeding intra-operatively in the failed coronectomy case. One patient had temporary lingual nerve paresthesia.
Coronectomy procedure is effective in controlling inferior alveolar nerve injury following third molar surgery, in radiographically evaluated high risk cases and it has very low incidence of complications.
在预防性或治疗性拔除下颌阻生第三磨牙后，医源性下牙槽神经（IAN）损伤是一个重要的危险因素。当通过影像学检查发现第三磨牙牙根与神经管重叠时，IAN损伤的风险会增加许多倍。人们提倡采用各种方法，如正畸辅助拔牙、分阶段拔牙或牙冠切除术，以降低高风险病例中IAN损伤的发生率，但其结果各不相同。
本研究的目的是通过口腔根尖片评估，对于下牙槽神经损伤高风险患者，在进行牙冠切除术或有意保留下颌阻生第三磨牙牙根后，牙根的转归情况（吸收、脱落、被骨覆盖）。
本研究纳入了18例患者的20颗下颌阻生第三磨牙，这些患者根据口腔根尖片检查结果，基于鲁德标准，属于IAN损伤高风险人群，年龄在18至40岁之间。术前对阻生第三磨牙进行临床和影像学评估。记录佩德森难度指数和阻生牙的温特分类。在牙骨质釉质界处进行牙冠切除术，使牙根位于牙槽嵴下方2 - 3毫米，并进行一期缝合。对患者进行为期两年的定期评估，每隔六个月进行一次。观察并记录术后疼痛、肿胀、IAN损伤或任何其他并发症。
所有患者均未发生IAN损伤，也无需二次手术拔除。没有术后感染的情况，也无需二次手术干预。然而，我们的两名患者（10%）因术中牙根松动导致牙冠切除术失败，牙根被拔除。在牙冠切除术失败的病例中，有一名患者术中出现大量出血。一名患者出现暂时性舌神经感觉异常。
在经影像学评估为高风险的病例中，牙冠切除术对于控制第三磨牙手术后的下牙槽神经损伤是有效的，且并发症发生率非常低。
