Evaluation of the visibility and the course of the mandibular incisive canal and the lingual foramen using cone‐beam computed tomography

Objectives: To assess the visibility and the course of the incisive canal and the visibility and the location of the lingual foramen using cone‐beam computed tomography (CBCT). Methods: In total, 100 CBCT examinations of patients for preoperative planning were used for this study. The examinations were taken using the NewTom 3G CBCT unit, applying a standardized exposure protocol. Image reconstruction from the raw data was performed using the NewTom software. Three experts were asked to assess the visibility of the incisive canal using a four‐point rating scale. The position of the incisive canal was recorded in relation to the lower, buccal and lingual border of the mandible using the application provided by the CBCT software. Results: The incisive canal was definitely visible in 83.5% of the scans and the mean endpoint was approximately 15 mm anterior to the mental foramen. The mean distance from the lower border of the mandible was 11.5 mm and its course was closer to the buccal border of the mandible in 87% of the scans. The lingual foramen was definitely visible in 81% of the scans. Conclusions: The high detection rate of the incisive canal and the lingual foramen in the anterior region of the mandible using CBCT indicates the potentional high preoperative value of CBCT scan for surgical procedures in the anterior mandible. To cite this article :
Makris N, Stamatakis H, Syriopoulos K, Tsiklakis K, van der Stelt PF. Evaluation of the visibility and the course of the mandibular incisive canal and the lingual foramen using cone‐beam computed tomography.
Clin. Oral Impl. Res. 21 , 2010; 766–771.
doi: 10.1111/j.1600‐0501.2009.01903.x     

Identification of the mandibular landmarks in a pediatric population

Objectives: The aim of this study was to determine and compare the reliability to accomplish of common mandibular landmarks and to determine the incidence of incisive canals, anterior looping, and lingual foramina in children from panoramic and CBCT images. Study Design: Panoramic and CBCT images from 100 children and adolescent patients were randomly selected. In order to grade the visibility of mandibular anatomical landmarks, a four-point rating scale was used. Results: In panoramic images, the mandibular canal could be observed in 92.5% of cases, with good visibility in 12.0%. The mental foramen could be observed in 44.5% of cases, while none had good visibility. Anterior looping of the mental nerve was present in 16.5% of the cases, and none had good visibility. An incisive canal could be identified in 22.5% of cases, with only 1.5% showing good visibility. The lingual foramen could be visualized in 61.0% of cases, with good visibility in 6%. In CBCT images, the mandibular canal, the mental foramen, and the lingual foramen could be observed in 100% of the cases, with good visibility in 51.0%, 98.5%, and 45.0% of cases, respectively. Anterior looping of the mental nerve was present in 26% of cases, with 2% having good visibility. An incisive canal could be identified in 49.5% of cases, with only 75% showing good visibility. Conclusions: This study confirms the applicability of CBCT images to visualize critical structures in children. Key words:Panoramic radiography, cone beam computed tomography, anatomical landmark.     

下颌骨颏孔前区解剖结构的锥形束CT研究

目的 通过锥形束CT（CBCT）分析下颌骨颏孔前区颌骨内的重要解剖结构,提出下颌颏孔前区种植相关手术的安全区域。方法 选取104例患者的CBCT图像资料,观察颏管、下颌切牙管、下颌舌侧管和舌侧孔。对数据进行描述性分析,计算均数和标准差。采用SPSS 19.0软件包对数据进行统计学分析。结果 颏管的发生率为55.29%,平均长度为1.12 mm。舌侧孔及舌侧管的发生率为94.23%,直径平均值为1.77 mm。从下颌第二前磨牙至中切牙,下颌切牙管距唇（颊）侧骨板的距离均小于距舌侧骨板的距离。结论 建议在颏孔前区种植手术或者颏部取骨时,以双侧颏孔前缘6 mm以上,唇侧骨厚度（取骨时）3 mm以内为安全界限;而在下颌前牙区种植时,种植体长度不超过14 mm。     

Assessment of the appearance,location and morphology of mandibular lingual foramina using cone beam computed tomography

Objectives: To investigate the appearance, location and morphology of mandibular lingual foramina (MLF) in the Chinese Han population using cone beam computed tomography (CBCT). Methods: CBCT images of the mandibular body in 200 patients (103 female patients and 97 male patients, age range 10–70 years) were retrospectively analysed to identify MLF. The canal number, location and direction were assessed. Additionally, the diameter of the lingual foramen, the distance between the alveolar crest and the lingual foramen, the distance between the tooth apex and the lingual foramen and the distance from the mandibular border to the lingual foramen were examined to describe the MLF characteristics. Gender and age differences with respect to foramina were also studied. Results: CBCT can be utilized to visualise lingual foramina. In this study, 683 lingual foramina were detected in 200 CBCT scans, with 538 (78.77%) being ≤1 mm in diameter and 145 (21.23%) being >1 mm. In total, 85.07% of MLF are median lingual canals (MLC) and 14.93% are lateral lingual canals (LLC). Two typical types of lingual foramina were identified according to their relationship with the tooth apex. Most lingual foramina (74.08%) were found below the tooth apex, and those above the tooth apex were much smaller in diameter. Male patients had statistically larger lingual foramina. The distance between the lingual foramen and the tooth apex changed with increasing age. Conclusions: Determination of the presence, position and size of lingual foramina is important before performing a surgical procedure. Careful implant-prosthetic treatment planning is particularly important in male and/or elderly patients because of the structural characteristics of their lingual foramina.Key words: Lingual foramen, lingual vascular canal, mandible, cone-beam CT     

Mandibular Incisive Canal: Cone Beam Computed Tomography

Purpose: Panoramic radiography is often used to analyze the anatomical structure of the teeth, jaws, and temporomandibular joints. Cone beam computed tomography (CBCT) imaging allows multiple axial slices of the image to be obtained through these anatomical structures. The aim of this study was to assess CBCT compared with panoramic radiography to verify the presence, location, and dimensions of the mandibular incisive canal. Materials and Methods: CBCT scan images and panoramic radiographs of 89 subjects were compared for the presence of the mandibular incisive canal, its location, size, and anterior‐posterior length. The distance between the incisive canal and the buccal and lingual plate of the alveolar bone, and the distance from the canal to the inferior border of the mandible and the tooth apex were also measured. A paired t‐test was used to calculate any significant difference between the two imaging techniques. Results: Eighty‐three percent of the CBCT scans showed the presence of the incisive canal, as did 11% of the panoramic radiographs. The range of the incisive canal diameter, as seen in the CBCT scans, was from 0.4 × 0.4 mm to 4.6 × 3.2 mm. The mean length of the canal was 7 ± 3.8 mm. The distance from the inferior border of the mandible to the canal was 10.2 ± 2.4 mm, and the mean distance to the buccal plate was 2.4 mm. The apex–canal distance (in dentate subjects) was 5.3 mm. Conclusion: The presence, location, and dimensions of the mandibular incisive canal are better determined by CBCT imaging than by panoramic radiography.     

下颌正中管的锥形束CT成像研究

目的 通过锥形束CT（CBCT）对下颌正中管（MIC）的三维位置、走向及毗邻关系进行测量,为确保颏孔前区域牙种植手术的安全提供依据。方法 回顾80例患者的双侧下颌骨CBCT影像,对MIC的直径和毗邻关系进行测量分析,包括MIC至下颌下缘、下颌牙根尖、下颌骨颊侧壁和舌侧壁,以及双侧颏孔连线平面的垂直距离。结果 80例患者中,63例（占78.75%）的CBCT影像上可以观测到MIC影像,其管径大小为（1.21±0.29）mm。在垂直方向上,MIC距下颌下缘和下颌牙根尖的距离分别为（7.82±1.86）、（7.24±2.82）mm;在颊舌方向上,MIC距下颌骨颊侧壁和舌侧壁的距离分别为（3.80±1.37）、（4.45±1.34）mm;MIC距双侧颏孔连线平面的垂直距离为（5.62±2.21）mm。结论 CBCT通过多平面重建后,可以清晰显示MIC在下颌骨中的三维空间位置、走向及毗邻关系;利用CBCT 对MIC的位置和走行进行研究是可行的。     

Stafne骨腔影像学特征：基于CBCT的回顾性分析

目的: 总结分析Stafne骨腔病例的锥形束CT（CBCT）影像学特征,以有效指导此类疾病的临床决策。方法: 收集山东大学口腔医院收治的6例Stafne骨腔病例,对其CBCT影像数据进行测量分析,分别记录其年龄、性别、主诉、病变位置、长宽高三径、多层面重建 （multiplanar reconstruction,MPR）三层面最大横截面积、内容物灰度、形态分类及与下颌神经管之间的关系等。结果: 6例患者均由CBCT检查无意发现。骨腔均位于下颌磨牙区后部及下颌角前部偏舌侧、下颌骨下缘与下颌神经管之间,呈类椭圆形,其长轴与下颌骨长轴相一致,平均长径（16.43±4.54） mm、宽径（6.91±1.48） mm、高径（10.24±2.10） mm。MPR层面中,骨腔最大横断面面积（91.93±25.52） mm²,最大冠状面面积（57.26±23.23） mm²,最大矢状面面积（127.80±51.22） mm²。按骨腔边缘线与颊侧骨皮质关系进行分类,Ⅰ型骨腔2例、Ⅱ型骨腔3例、Ⅲ型骨腔1例。根据矢状面上骨腔边界与下颌骨下缘及下颌神经管之间的相对位置,将骨腔与周围解剖结构的连接关系分为连通、毗邻、远离3种情况;而CBCT校正后,骨腔中心灰度可初步鉴别内容物类型。结论: CBCT可对Stafne骨腔作出较为直观明确的诊断,影像学表现对早期临床决策具有重大参考意义,可避免不必要的手术,减少额外医疗资源浪费及患者身心创伤。     

下颌骨前突患者下颌管走行及临床价值探讨

目的：：运用锥形束CT(cone-beam CT,CBCT)分析正常人群和下颌骨前突患者下颌神经管轨迹,为临床手术方案的制订和操作时避开重要神经血管提供帮助。方法：选取28例骨性Ⅲ类下颌骨前突患者（男10例,女18例）、20例正常对照组患者（男12例,女8例）,使用CBCT拍摄下颌管影像,从下颌孔至第一磨牙区分为5个平面,在每个层面分别测量下颌管内外径、下颌骨厚度、下颌管至颊舌侧骨皮质及下颌骨下缘的距离。采用SPSS 17.0软件包对测量结果进行统计学分析。结果：下颌骨前突患者自下颌支到下颌角前部逐渐增厚,继续至下颌第一磨牙区逐渐变薄。下颌神经管的内外径自下颌支到下颌体部逐渐变细。颊侧骨皮质厚度自下颌支区域逐渐增厚,到下颌体部继续变薄。下颌骨前突患者与对照组患者下颌管的对比分析显示,骨髓腔宽度与下颌支厚度有显著差异,且具有显著相关性。结论：CBCT能够精确显示下颌神经管的走行及与周边结构的关系,下颌骨前突患者与对照组患者下颌支厚度的差异主要由颊侧骨髓腔宽度造成。     

Observation of the retromolar foramen and canal of the mandible: a CBCT and macroscopic study

Objectives  

The retromolar foramen (RMF) is an anatomical structure on the alveolar surface of the retromolar area. This foramen runs consecutive to the retromolar canal (RMC), which diverges from the mandibular canal. It is important to confirm the RMF and canal locations prior to surgical procedures, such as extraction of an impacted molar and bone harvesting as a donor site for bone graft surgery. This aim of this study was to investigate the RMF in Japanese cadaver mandibles using cone-beam computed tomography (CBCT) images and anatomical observations.     

基于锥形束CT影像对下颌管解剖变异的系统评价

目的 基于锥形束CT(cone beam computed tomography,CBCT)影像进行解剖学研究的系统评价,以评估下颌管变异及其解剖学发生率.方法 在PubMed、Cochrane、CNKI数据库中搜索2005年1月至2019年12月关于成年人群下颌管解剖变异的相关文章,并采用随机效应模型对其进行分析.通...     

Presence and course of the mandibular incisive canal and presence of the anterior loop in cone beam computed tomography images of an Iranian population

Objectives  

To assess the presence, location, and course of the incisive canal and the presence of the anterior loop using cone beam computed tomography (CBCT) in a selected Iranian population.     

基于CBCT的西南地区汉族人双下颌管形态学研究

目的：利用CBCT分析西南地区汉族人双下颌管发生的概率及各型双下颌管的形态学特征,为与之密切相关的口腔临床操作提供参考。方法：选择 2014-2016年期间于自贡市第四人民医院口腔科就诊拍摄CBCT的汉族患者300例,观察患者有无双下颌管,描述其形态学特征并进行统计学分析。结果：西南地区汉族人双下颌管的发生率为19.33%。其中,磨牙后管占比最高（58.75%）,其次为根尖管（23.75%）和前行管（15.00%）,颊舌向管最少（2.50%）。结论：基于CBCT的研究表明西南地区汉族人双下颌管有较高的发生率,并且各型分支存在形态学差异,临床工作中需重视其影响。     

Using cone beam computed tomography to determine safe regions for implant placement

This study sought to identify and follow the course of the incisive canal in the mental interforaminal region of the human mandible and to describe other anatomical landmarks present in this region. Cone beam computerized tomography (CBCT) studies for 40 patients were collected from the database at the Department of Oral & Maxillofacial Radiology, School of Dentistry, Lebanese University. Ten patients had edentulous mandibles; the other 30 had partially or completely dentate mandibles. Axial native images and panoramic and cross-sectional reconstructions were examined to assess the anatomical landmarks in the anterior mandible. Multiple neurovascular canals and foramina were clearly detected on CBCT studies of the mandible. Numerous foramina were seen on the internal surface of the mandible, even distant from the midline. The incisive canal was identified in 97.5% of the images. These anatomical landmarks should be evaluated carefully during preoperative planning.     

锥形束CT在下颌第二磨牙C形根管系统应用的研究

目的　采用锥形束CT（简称CBCT）研究下颌第二磨牙C形根管的解剖形态,为根管治疗提供更加直观的影像学依据。方法　使用CBCT观察441例患者双侧下颌第二磨牙,统计C形根管的发生率以及根管形态。结果　C形根管的发生率为41.72%,C形根管类型变化多样,C形根管的发生率在性别、年龄间无统计学差异。结论　C形根管在下颌第二磨牙有很高的发生率,并且解剖形态有较大差异,CBCT在诊断C形根管方面具有重要作用。     

锥体束CT对维吾尔族成人下颌第二磨牙C形根管的研究

目的: 通过锥体束CT(cone-beam computed tomogphy,CBCT)成像系统对新疆维吾尔族成人下颌第二磨牙C形根管的发生率及其形态特征进行研究。方法: 选择来我院体检且下颌牙列完整的100名维吾尔族成人,进行CBCT扫描,观察下颌第二磨牙的根管形态。结果: C形根管的发生率为15.0%,C 形根管类型变化多样。结论: C形根管在下颌第二磨牙有较高的发生率,且解剖形态存在较大差异。CBCT在C形根管的诊断方面具有重要作用,可以为维吾尔族成人下颌第二磨牙C形根管的临床诊疗提供依据。     

下颌中切牙唇倾度与牙槽骨厚度关系的锥形束CT分析

目的应用锥形束CT（CBCT）测量分析下颌中切牙不同唇倾度与牙槽骨厚度的关系。方法选择60例患者的头颅侧位片和CBCT影像资料,按照下颌中切牙-下颌平面角（L1-MP）分为3组,即舌倾组L1-MP<85.6°;正常组L1-MP为85.6°~99.6°;唇倾组L1-MP>99.6°。三维重建CBCT,在矢状面图像上沿下颌中切牙长轴,选择牙槽骨截面最大的图像,将牙根从釉牙骨质界到根尖点平均分为4段,测量唇、舌侧牙槽骨厚度并合计得到总厚度,观察计数骨开窗及骨开裂发生情况。采用SPSS17.0软件包对数据进行统计学分析。结果舌侧及总牙槽骨厚度在各测量位点间的差异均有统计学意义。根中1/2、根尖1/4及根尖处牙槽骨厚度唇侧均小于舌侧。舌侧牙槽骨厚度在各测量位点均为舌倾组小于唇倾组, 牙槽骨总厚度在根尖、根尖1/4、根中1/2处舌倾组比唇倾组薄。唇倾组和舌倾组的骨开裂发生率均高于正常组,差异显著(P<0.05)。结论下颌中切牙舌侧及总牙槽骨厚度从根尖区到根颈区逐渐变小,舌倾组舌侧及牙槽骨总厚度比唇倾组薄,下颌中切牙牙轴过度唇倾或舌倾易发生骨开裂。     

锥形束计算机体层摄影术观察下牙槽神经管形态及其临床意义

目的 应用锥形束计算机体层摄影术（CBCT）观测并分析下牙槽神经管在下颌骨内的走行特点,探讨其分布规律,为临床手术提供解剖学依据.方法 采用单纯随机抽样法选取具备下颌后部CBCT 扫描数据的患者60 例,应用CBCT 自带的KaVo eXam Vision 软件测量颏孔区、前磨牙区、磨牙区下牙槽神经管与牙槽嵴顶、下颌骨颊舌侧骨板及下缘的平均距离,对各组测量项目进行成组t 检验比较,并观察其走行特点.结果 下牙槽神经管距下颌下缘小于距牙槽嵴顶的距离,在第二磨牙区距离下颌骨下缘最近;颏孔区至第一磨牙区间,下牙槽神经管距颊侧骨板距离小于距舌侧骨板距离,自第二磨牙后,下牙槽神经管距颊侧骨板距离则大于距舌侧骨板距离;性别及左、右侧下牙槽神经管距离差异无统计学意义（t＝2.437,P ＞ 0.05）.结论 CBCT 扫描有利于更好了解下牙槽神经管的走行及结构特异性,对牙槽外科及种植外科手术方案的制定具有一定临床指导意义.     

Appearance of anatomical structures of mandible on panoramic radiographs in Iranian population

Abstract

Purpose. Currently panoramic radiography is used for diagnosis of dental and bone lesions, but anatomical structures also can be seen and may be useful in dental managements. This study aimed to investigate the visibility of some important mandibular features relating to neurovascular structures in Iranian population. Materials and methods. Panoramic radiographs were taken by Planmeca machine from 412 patients using standard exposure. The position of patient was in compliance with standard protocol. Then mandibular incisive canal was evaluated and data were analyzed statistically. Results. Mental foramen, anterior loop of mental nerve and incisive canal could be observed in 84.2, 66 and 51.7% of the cases. Respectively, lingual foramen was observed in only 6.1% of the radiographs. Gender doesn't affect on the visibility of these structures. There was a relationship between mandibular foramen and canal with age. Conclusion. Mandibular incisive canal was considered in 51.7% of cases, it was observed that the result obtained was more than those of other researches.     

Macroanatomic and radiologic characteristics of the superior genial spinal foramen and its bony canal

PURPOSE: To determine the incidence, size, location, course, and content of the superior genial spinal foramen and its bony canal. MATERIALS AND METHODS: Three hundred eighty dry human cadaver mandibles were morphometrically analyzed by measuring the distance from the foramen to the mandibular base and the size of the foramen and bony canal. Radiologically, the course of the bony canal and its relation to the mandibular incisive canal were investigated after injecting contrast medium (Omnipaque) in the superior genial spinal foramen and the incisive canal at the level of the mental foramen or by inserting a thin metal wire into the bony canal. Dissection was performed on another 10 intact cadaver mandibles. RESULTS: A distinct foramen was present in 98% of all dry specimens studied. Its general form was round or flattened funnel-shaped. Upon microanatomic dissection, a distinct branch of the lingual artery and the lingual nerve entering the superior genial spinal foramen were found. CONCLUSIONS: The superior genial spinal foramen is present in most human mandibles and appears to be the entrance of a true lingual neurovascular bundle passing into the bone via a well-defined bony canal toward the buccal side. This implies that surgery and more specifically implant placement at the mandibular midline may carry some risk of neurovascular damage.     

Variations of the bony canal in the mandibular ramus using cone-beam computed tomography

The location and configuration of the mandibular canal are important in surgical procedures involving the mandible. Previously, we reported that bifid mandibular canals could be classified into four types: retromolar, dental, forward, and bucco-lingual canals, using cone-beam computed tomography (CBCT). Herein we report three Japanese patients with a bony canal in the mandibular ramus, which was independent of the mandibular canal, using CBCT images. A CBCT unit with a flat panel detector and exposure volume of 102 mm in diameter and 102 mm in height was used. Two-dimensional (2D) and three-dimensional (3D) images in the mandibular ramus region were reconstructed using 3D visualization and measurement software packages. Three bony canals in two patients were considered to correspond to a temporal crest canal, which was raised from the mandibular notch, and reached the antero-inferior region of the coronoid process. One bony canal in one patient, ran bucco-lingually in the mandibular ramus. It is important for variations in the mandibular and bony canals to be carefully observed, by use of CBCT images, in surgical procedures involving the mandible.