下牙槽神经损伤的评估与治疗

下牙槽神经损伤是牙科手术术后常见的严重并发症之一。下牙槽神经损伤可引起患者下唇、颏部、牙龈等区域感觉迟钝、异常或疼痛,对患者生理和心理造成负面影响。了解下牙槽神经损伤病因有利于预防神经损伤的发生。对于已发生的神经损伤,准确可靠的诊断与治疗策略有利于神经损伤的后期恢复。本文就下牙槽神经损伤的病因、评估及治疗作一综述,为临床工作提供指导。     

Evaluating the risk of post-extraction inferior alveolar nerve injury through the relative position of the lower third molar root and inferior alveolar canal

The aim of this study was to introduce a method to evaluate the risk of inferior alveolar nerve (IAN) injury following the extraction of impacted lower third molars. Two hundred impacted lower third molars adjacent to the IAN were evaluated. These were divided into four classification groups according to preoperative cone beam computed tomography (CBCT) findings: AR, apical region; LT, lateral region of the tapered root; LE, lateral region of the enlarged root; AE, adjacent to the enlarged root. All teeth were dislocated along the long axis or arc of the root by tooth sectioning technique and extracted by a single surgeon. The primary outcome variable was postoperative neurosensory impairment of the IAN. The χ² test was used to evaluate differences in postoperative IAN injury between the classifications. Logistic regression analysis was used to evaluate the risk factors for postoperative IAN injury. The overall incidence of postoperative IAN injury was 7%. Specifically, most injuries involved classification AE (AE 36%, LE 8.6%, LT 3.6%, AR 0%), and the difference was statistically significant (P <  0.05). Logistic regression showed that classification AE was the only risk factor for postoperative IAN injury (P <  0.001). According to preoperative CBCT, the risk of postoperative IAN injury is higher when the IAN is adjacent to the enlarged part of the root.     

冠根分次去除法在疑或累及下牙槽神经的下颌第三阻生磨牙拔除术中的应用

目的:评价应用截冠法分次拔除紧贴下牙槽神经的下颌阻生第三磨牙的效果。方法:对10例术前全景片及CT均显示牙根紧贴或接触下牙槽神经的下颌阻生第三磨牙患者采用截冠留根法,于釉-牙骨质界去除阻力牙冠,包埋牙根于牙槽骨内;术后观察,待牙根移动远离下牙槽神经后再行拔除术。结果:10例患者术后反应轻微,均无下牙槽神经损伤,无感染情况出现;仅1例牙根未能上移至远离下牙槽神经的位置,留根于牙槽骨内,牙龈创面愈合,随访1年无不适。结论:根尖紧贴或接触下牙槽神经的下颌阻生第三磨牙,经截冠留根术后,断根有上移萌出趋势,可远离下牙槽神经管,后期拔除断根,可明显降低下牙槽神经损伤的风险。     

正畸牵引法辅助拔除接触下牙槽神经管的埋伏阻生牙1例报告

阻生下颌第三磨牙拔除是口腔颌面外科的一种常见手术.由于低位阻生的下颌第三磨牙牙根位置常与下牙槽神经(inferior alveolar nerve,IAN)关系密切,神经损伤是该手术的严重并发症之一.目前,国际上主要有3种避免IAN损伤的方法:截冠法、部分牙冠切除术和正畸牵引法.本文报告1例下颌第三磨牙近中斜位低位阻生的患者,采用改良正畸牵引法,分两步将牙根牵离神经管,牵引完成后顺利拔除患牙.     

牵引拔除压迫下牙槽神经的下颌第三磨牙

目的：应用牵引技术拔除压迫下牙槽神经的下颌第三磨牙,以减少术后并发症。方法：对20例全景片和CT显示下颌第三磨牙牙根压迫或紧贴下牙槽神经的患者,先应用正畸牵引技术牵引,经3～10周的牵引,使牙根远离下牙槽神经后再行拔除术。结果：20例牙根压迫下牙槽神经的患者,经牵引拔牙后,无1例发生下唇麻木,术后反应轻微。结论：应用牵引拔牙技术拔除下颌第三磨牙,解决了术后下唇麻木、骨折等高风险并发症的发生,也使拔牙更容易、更快。     

下颌近中阻生第三磨牙拔除方法与神经损伤危险因素分析

目的: 调查分析下颌近中阻生第三磨牙拔除术后牙槽骨缺损及下牙槽神经（inferior alveolar nerve,IAN）损伤发生的影响因素,为今后制定更具针对性的预防措施提供参考。方法: 回顾性调查分析500例口腔门诊顺利完成下颌近中阻生第三磨牙拔除术患者的临床资料、影像学资料、随访资料等,对比分析发生与未发生牙槽骨缺损及神经损伤患者的资料,明确危险因素。采用SPSS18.0软件包进行Logistic回归分析,研究发生牙槽骨缺损及神经损伤的独立危险因素。结果: 500例患者中,52例 (10.40%)发生IAN损伤。经单因素分析和Logistic回归分析发现,患者年龄、手术切口、拔牙器械、拔牙术方案、术后其他并发症（血肿、感染、干槽症）均为下颌近中阻生第三磨牙拔除术后牙槽骨缺损及神经损伤的危险因素（P<0.05）。结论: 术前充分考虑患者年龄、下颌阻生第三磨牙的阻生形态、解剖结构、牙根和下颌管位置关系,进而评估拔除风险、个性化拟定手术方案并选择最佳的手术器械,可预防术后并发症的发生。     

Novel strategy to predict high risk of inferior alveolar nerve injury during extraction of lower third molars based on assessment of computed tomographic images of multiple anatomical features

Preoperative assessment is essential to prevent inferior alveolar nerve (IAN) injury during surgical extraction of the lower third molar (LM3). Here, we aimed to establish an assessment system to predict IAN injury during surgical extraction of the LM3. We conducted a retrospective cohort study on 115 patients diagnosed as ‘high-risk’ based on our previous risk assessment method involving three anatomical features of the inferior alveolar canal using computed tomographic (CT) images. We evaluated the occurrence of neurosensory impairment in these high-risk patients, and its association with novel anatomic features based on CT images. Neurosensory impairments were observed in 19 patients (16.5%). The inferior alveolar canal major diameter (p < 0.0001) and lingual bone thickness (p = 0.0039) were significantly associated with the occurrence of neurosensory impairment during LM3 extraction. Receiver operating characteristic curves were used to determine cut-off values of these quantitative factors to specifically predict IAN injury. Preoperative risk assessment with quantitative factors based on anatomical features observed on CT images may facilitate more appropriate surgical planning for patients at a high risk of IAN injury.     

Inferior alveolar nerve demage following removal of mandibular third molar teeth. A prospective study using panoramic radiography

Permanent alteration of sensation in the lip after the removal of mandibular third molar teeth is an unusual but important complication. Studies have been performed to assess the risk of nerve damage but most of these have been retrospective and poorly controlled.
This prospective trial predicted the outcome of altered sensation prior to surgery based on assessment of a panoramic radiograph and correlated this with the result postoperatively in the consecutive removal of 479 third molar teeth.
Result indicated that 5.2 per cent had transient alteration in sensation but only one patient (0.2 per cent) had prolonged anaesthesia. As 94.8 per cent of teeth extracted had no neurological sequelae the figures for prediction were skewed and a kappa statistical analysis of 0.27 illustrated a fair level of agreement between prediction and outcome.
This study supports previously reported levels of neurological damage and confirms that panoramic radiography is the optimum method for radiological assessment for mandibular third molar teeth prior to their removal.     

Anatomic relationship between impacted third mandibular molar and the mandibular canal as the risk factor of inferior alveolar nerve injury

Our aim was to explore the relation between the site of the mandibular canal and neurosensory impairment after extraction of impacted mandibular third molars.     

Pre-operative assessment of relationship between inferior dental nerve canal and mandibular impacted third molar in Saudi population

ObjectiveTo study the correlation between the position of the inferior dental (ID) nerve canal and the angulation of impacted mandibular third molars using dental cone beam computed tomography (CBCT).Materials and methodsThe study considered 100 impactions in 85 patients (60 males, 25 females), for whom an initial panoramic radiographic assessment had revealed that the ID canal and the lower 3rd molar were in close proximity. A CBCT scan of each patient was carried out to assess how the ID nerve canal position influenced the class and position of impaction, angulation of impaction, and bone contact.ResultsClass I position B impactions were found in the majority of cases, where the position of the ID canal was approximate to the lingual plate and inferior to the 3rd molar (85.7%). The results were statistically significant (p = 0.001). 96% of the ID canals showed bone contact. Of these, 77.1% of ID canals exhibited lingual bone contact, inferior to impaction. The results were statistically significant (p = 0.001). Horizontally angulated impactions were most common in the mandible, and significantly associated with lingual and inferior positioning of the ID canal (76.2%).ConclusionsOur sample population most commonly exhibited horizontally angulated class I position B impactions of the mandible. The position of the ID canal significantly influenced the type of impaction and bone contact.     

改良Gow-Gates下牙槽神经阻滞麻醉在下颌阻生第三磨牙拔除术中的应用

目的:探讨一种微创高效的下牙槽神经阻滞麻醉方法。方法:将206例门诊拔除下颌阻生第三磨牙患者随机分为2组,实验组105例采用改良Gow-Gates法,对照组101例采用传统口内注射法（Halstead法）。记录麻醉成功率、麻醉效果和并发症,采用SPSS17.0软件包对数据进行统计学分析。结果:改良Gow-Gates法麻醉成功率为97.15%,Halstead法为89.10%,2组间显著差异（P=0.038）。改良Gow-Gates法在麻醉效果A、B级比率为90.48%,Halstead法为87.13% ,2组间无显著性差异（P=0.446）。改良Gow-Gates法的并发症显著少于Halstead法（P=0.014）。结论:Gow-Gates下牙槽神经阻滞麻醉是一种微创高效的麻醉方法。     

Risk of inferior alveolar nerve injury with coronectomy vs surgical extraction of mandibular third molars—A comparison of two techniques and review of the literature

The removal of mandibular third molar teeth is one of the most common oral surgical procedures. In a significant number of patients, it carries a degree of associated morbidity, including damage to the inferior alveolar nerve (IAN). For this reason, practitioners desire the most up‐to‐date guidance on the most appropriate technique, informed by the best available evidence that will produce the lowest incidence of iatrogenic complications. The aim of this study was to perform a systematic review comparing the effect of coronectomy vs complete surgical extraction of mandibular third molar teeth on the risk of IAN injury and other complications in adults. Studies were identified through Embase (1980‐2016) and Ovid MEDLINE (1946‐2016) database searches. Search terms included coronectomy, partial root removal, deliberate vital root retention, odontectomy, surgical removal, surgical extraction, complete tooth extraction and extract. Limits of the study included humans, English language and randomised controlled trials (RCTs). Only RCTs comparing IAN damage associated with surgical extraction of mandibular third molars vs coronectomy were included. From our database searches, we identified two unique RCTs matching the inclusion criteria. Both evaluated patients who had specific radiographic signs of intimate relationships with the IAN. Upon detailed analysis, the studies were noted to exhibit a high risk of bias in many categories, thereby rendering their results inconclusive. Although evidence from two RCTs suggests that coronectomy can reduce the risk of IAN injury compared to surgical removal of high‐risk mandibular third molars, the quality of evidence is insufficient to provide definitive conclusions regarding the preferred technique.     

Influence of BSSO surgical technique on postoperative inferior alveolar nerve hypoesthesia: A systematic review of the literature

ObjectiveThe aim of this study was to evaluate the influence of different splitting techniques, namely, “mallet and chisel” versus “spreading and prying”, used during bilateral sagittal split osteotomy (BSSO) on postoperative hypoesthesia outcomes.Study designWe systematically searched the PubMed and Cochrane databases (from January 1957 to November 2012) for studies that examined postoperative neurosensory disturbance (NSD) of the inferior alveolar nerve (IAN) after BSSO.ResultsOur initial PubMed search identified 673 studies, of which, 14 met our inclusion criteria. From these 14 studies, 3 groups were defined: (1) no chisel use (4.1% NSD/site), (2) undefined chisel use (18.4% NSD/site), and (3) explicit chisel use along the buccal cortex (37.3% NSD/site).ConclusionStudy heterogeneity and a frequent lack of surgical detail impeded our ability to make precise comparisons between studies. However, the group of studies explicitly describing chisel use along the buccal cortex showed the highest incidence of NSD. Moreover, comparison of the study that did not use chisels with the 2 studies that explicitly described chisel use revealed a possible disadvantage of the “mallet and chisel” group (4.1% versus 37.3% NSD/site). These results suggest that chisel use increases NSD risk after BSSO.     

Gow-Gates法下牙槽神经阻滞麻醉在下颌阻生第三磨牙拔除术中的麻醉效果研究

目的 通过临床随机对照试验的方法评价Gow-Gates法下牙槽神经阻滞麻醉在下颌阻生第三磨牙拔除术中的麻醉有效性和安全性。方法 使用左右半口设计,32例患者的左右下颌阻生第三磨牙分别随机采用Gow-Gates法和传统注射法进行下牙槽神经阻滞麻醉,并拔除下颌阻生第三磨牙,记录麻醉效果及不良事件。结果 所有患者均完成研究。Gow-Gates法的麻醉成功率为96.9%,传统注射法的麻醉成功率为90.6%,二者的麻醉成功率无统计学差异（P=0.317）。在麻醉程度上,Gow-Gates法麻醉程度为A和B级的比率为96.9%,明显好于传统注射法的78.1%（P=0.034）。Gow-Gates法的回抽出血率明显低于传统注射法（P=0.025）,2种注射方法均未出现血肿。结论 Gow-Gates法下牙槽神经阻滞麻醉在下颌阻生第三磨牙拔除术中的麻醉效果好且较为安全,可以作为传统注射法的有效补充。     

Inferior Alveolar Nerve Deficits and Recovery Following Surgical Removal of Impacted Mandibular Third Molars

Aims and Objectives

(1) To determine the incidence of inferior alveolar nerve (IAN) deficits following surgical extraction of mandibular third molar.(2) To document recovery of IAN injuries.

Materials and Methods

A total of 400 lower third molars were extracted, 205 male patients and 195 females. All underwent extraction by the prescribed buccal approach. All cases were examined by one examiner preoperatively and postoperatively, at 7 days, one month, two months and six months. Two-point discrimination test (2-pd), brush stroke direction (BSD), contact detection, pin prick and thermal testing was carried out.

Results and Conclusion

One patient presented with IAN injury (0.25%). This single case of nerve injury was mesioangular, Level B, Class 2, impaction with a difficulty rating of 5. Levels A and B tests (2PD, BSD, Contact detection) were altered. In these tests, the IAN did not show any signs of recovery by six months. Level C tests (pin prick test, sharp blunt detection) showed that the nerve had recovered completely by two months.     

以下颌神经管为参照的下颌阻生第三磨牙的分类及临床意义

目的：以下颌神经管为参照,探讨与下颌神经管(inferior alveolar canal,IAC)相交的下颌阻生第三磨牙(impacted mandibular third molars,IMTMs)的阻生类型,并观察手术拔除阻生牙后下牙槽神经损伤与阻生类型间的关系。方法：对锥形束CT(cone beam computed tomography,CBCT)确诊为下颌阻生第三磨牙与下颌神经管接触或相交的378例患者共658侧阻生牙,以下颌神经管为参照,将阻生牙分为4类：Ⅰ类位于神经管的上方,Ⅱ类位于神经管的颊侧,Ⅲ类位于神经管的舌侧,Ⅳ类下颌神经管位于牙根之间。所有病例均采用手术拔除,术后观察容易引起下牙槽神经损伤的阻生类型,统计各种类型神经损伤的例数,应用SPSS13.0软件包对数据进行χ²检验。结果：阻生牙拔除后,下牙槽神经损伤率为6.8%(45/658)。其中,第Ⅰ类15例(15/332)发生下唇麻木、第Ⅱ类19例 (19/108) 发生下唇麻木、第Ⅲ类11例(11/210)发生下唇麻木,第IV类未发生下唇麻木(0/8)。统计学分析显示,阻生牙拔除后,第Ⅰ类和第Ⅱ类、第Ⅱ类和第Ⅲ类下牙槽神经损伤率有显著差异(P<0.01),第Ⅰ类和第Ⅲ类之间无显著差异(P>0.05)。结论：以下颌神经管为参照,CBCT冠状位可将下颌阻生第三磨牙与下颌神经管相交的患者分为4类,手术拔除过程中均有损伤下牙槽神经的危险,尤其是位于下颌神经管颊侧的阻生牙。     

微创拔除压迫下牙槽神经的第三磨牙方法分析

目的: 应用牵引拔牙、截冠和超声骨刀微创拔牙技术拔除压迫下牙槽神经的第三磨牙,观察术后产生下唇麻木等并发症的发生情况。方法: 选择60例全景片和锥形束CT（CBCT）显示下颌第三磨牙牙根压迫下牙槽神经的患者,分别采用3种方法拔牙各20例,术后检查下唇麻木情况。结果: 应用牵引拔牙技术和截冠方法拔除压迫下牙槽神经的第三磨牙,术后无人发生下唇麻木,而应用超声骨刀微创拔牙的患者中有1例出现轻微的下唇麻木症状,经用药1个月后好转。结论: 牵引拔牙技术、截冠和超声骨刀3种方法均可有效避免智牙拔除后下唇麻木的并发症。     

Perineural infiltration of the inferior alveolar nerve in mandibular ameloblastomas

Our aim was to evaluate the histological association of mandibular solid and multicystic ameloblastoma with the inferior alveolar nerve, both in situ and in segments of the nerve that had been removed separately, to assess the feasibility of preserving the nerve during resection of mandibular ameloblastomas. In this prospective histological examination of 13 resected hemimandibulectomy specimens, we studied the proximity of tumour cells to the inferior alveolar nerve. In group 1 (n = 8) this association was examined with the nerve still within the mandibular segment after resection, while in group 2 (n = 5) the nerve was removed from the resected tumour and examined separately. Perineural and intraneural involvement of the ameloblastoma with the nerve was confirmed in 5 cases in group 1 and 2 cases in group 2. Tumour cells abutted the nerve directly in group 1. In group 2 tumour was removed with, and found within, the nerve. On this evidence we cannot recommend preservation of the inferior alveolar nerve during operation for large, advanced, mandibular ameloblastomas.