The Anatomical Research on the Mental Foramen Related to the Mental Nerve Block

Objective: The aim of this study was to observe and investigate the location of mental foramen, providing scientific and reasonable anatomic basic for clinical mental nerve block. Methods: The shape, orientations, relationship with teeth and number of accessory mental foramina in 50 (100 side) adult mental foramina were observed. The long and short diameters of the mental foramen and the distance between the mental foramen and the peripheral anatomical markers were measured by a vernier caliper, and statistical analysis of the data was performed to obtain the final results. Results: The probability of mental foramen being elliptical in shape accounted for 27%, circular for 73%;10% of the mental foramen openings are outward and 90% are outward and upward;The mental foramina were located under the first premolars in 20%, under the second premolars in 75%, and 5% situated in the bottom of the first molars. The incidence of accessory mental foramina was 1%;the long diameter of the mental foramen was (2.42 ± 0.71) mm, and the short diameter of the mental foramen was (2.15 ± 0.14) mm;the vertical distance from the mental foramen center to the alveolar crest and the lower margin of the mandible were (14.09 ± 3.23) mm and (14.56 ± 1.74) mm;the distance between the midpoints of the vertical line to the center of the mental foramen was (1.26 ± 0.97) mm;the horizontal distance from the center of the mental foramen to the anterior median line was (23.57 ± 1.82) mm. Conclusion: The point of mental nerve block was selected below and behind the second premolars, above the midline of the mandible. The distance from the anterior median line was 2.5 cm, and the mental foramen was explored forward and downward after the insertion.

Accessory Mental Foramen Misdiagnosed as Radiolucent Tumour by Conventional Dental Radiography

The mental foramen is an important landmark for identifying the mental nerve, and the accessory mental foramen is a rare anatomical variation. This article describes the use of computed tomo- graphy (CT) to detect an accessory mental foramen that was initially misdiagnosed as a radiolu- cent tumour in the right premolar region of a 39-year-old woman by panoramic radiography. The case suggests that preoperative CT should be performed to detect any anatomical variations. This knowledge would help in diagnosis, preoperative planning and prevention of intraoperative nerve or vascular injury.

Role of the mental foramens in dolphin hearing

The role of mental foramens in dolphin hearing was studied in the present work. To this effect the mental foramens’ morphology features which are essential from acoustical viewpoint have been studied. The patterns of relationship between the location of mental foramens and their sizes are found. The affinity of the mental foramens’ morphology and acoustics that the nature had created testify acoustical expediency of the mental foramens’ architecture. This natural inference in the main is confirmed in this work by the experimental data. The mean values of detection thresholds of short broadband stimuli with spectral maximum on frequencies 8, 16, 30 and 100 kHz at acoustical shielding the mental foramens increased on 30, 34, 40 and 50 dB, respectively. Results obtained testify that the mental foramens are the unique sound-conducting pathway into the fat body of the mandibular canal for the sounds of all frequencies used in the experiment, approximately 6?150 kHz (in view of stimuli broadbandness). The left and right row of the mental foramens together with respective mandibular canal plays the role of pinna and external auditory meatus if to use conventional terminology of a land mammal ear. But it is already qualitatively the new external ear implemented by the nature as the receive array and acoustical horn. The new external ear has apparently appeared in result of the dolphins’ ancestors’ adaptation to new environment conditions, as evolutionary adaptation of the ear to the water and as functional adaptation of the ear in order that to fulfill the new more sophisticated functions in the structure of sonar. The findings give good reason to suppose existence of the same external ear in Odontoceti.

Mental Foramen:A Predictor of Age and Gender and Guide for Various Procedures

Background:The distance from the inferior border of mental foramen(MF)to lower border of mandible remains constant throughout the life.Considering this fact the present study was carried out to determine role of MF in age and gender estimation and also its importance in planning various treatments.Aims and Objective:(1)To determine the most common type and shape of MF 2)To measure the height of the mandibular body(H),the distance between the superior margin of the MF to the alveolar crest(SM-AC),the distance between the superior margin of the MF to the inferior border of the mandible(SM-IB),the distance between the inferior margin of the MF to the inferior border(IM-IB)on the right side and left side.(3)To compare the above measurements for age and gender determination.(4)To determine effect of various factors on above measurements(5)to evaluate whether any significant difference in measurement occurs on right and left side.(6)To derive a regression equation for age estimation.Materials and Methods:A total of 300 Orthopantomogram were studied.Measurements such as H,SM-AC,SM-IB and IM-IB were carried out on both sides on type II MF in males and females in all the six age groups.Statistical analysis was carried using IBM SPSS version 24 to determine differences in measurements and linear regression analysis was carried out to determine age of individuals.Result:The most common appearance of MF was type II and shape was oval.Statistically significant differences occurred in measurements using which regressive equation for age estimation was derived for males&females.Conclusion:MF,being a stable landmark in mandible,serves as a good indicator for the determination of age and gender.Hence,using certain measurements related to MF,it can help in determining the age of the individual.Further,its position and distance from the alveolar crest serve as a guide for orthognathic surgeries,implant placement,and pre-prosthetic surgery.

Pre-mental foramen mandibulotomy for resecting tumors of tongue base and parapharyngeal space

Background Resection of tumors arising from the tongue base and the parapharyngeal space is difficult for exposure and manipulation because of their obscure location. The aim of this study was to evaluate the surgical approach of the pre-mental foramen mandibulotomy for resecting the tumors of tongue base and parapharyngeal space. Methods Fifty-one patients with tumors of tongue base and parapharyngeal space were treated using the mandibulotomy approach on the pre-mental foramen. In the present study, this technique was described in detail. The patients were followed up for three months to six years with a mean of 26 months. Results The tumors of tongue base and parapharyngeal space could be exposed clearly and be resected radically by surgical approach of pre-mental foramen mandibulotomy. The surgical complications were reduced. Conclusions Compared to other surgical approaches, such as lateral mandibulotomy, midline mandibulotomy, the suprahyoid parapharyngeal approach, and paramedian mandibulotomy, we found that the pre-mental foramen mandibulotomy is the ideal choice for resecting the tumors of tongue base and parapharyngeal space.

正颌手术眶下孔和颏孔定位的CBCT研究

目的:通过研究眶下孔(infraorbital foramen, IOF)相对于前鼻棘点(anterior nasal spine, ANS)的位置关系及颏孔(mental foramen, MF)相对于颏前点(pogonion, Pog)的相对位置关系,来为正颌外科手术提供更精准的定位参考。方法:随机选取115例年轻患者的锥形束CT(cone-beam CT)图像。利用Mimics 15.0软件分析IOF和ANS、MF和Pog之间的相对位置。结果:ANS比IOF低21.40 mm,两者间的水平距离为26.42 mm。MF和Pog间的水平和垂直距离分别为23.57 mm和9.71 mm。以ANS为中心的散点图显示,83%(191/230)的IOF位于半径为30~40 mm的30~45°扇形区域内。以Pog为中心的散点图显示,98%(226/230)的MF位于半径为20~30 mm的45°扇形区域内。结论:为规避直接损伤眶下神经血管束,术者在行上颌骨截骨术时需在不高于ANS点21.40 mm的区域操作。过度地牵引黏骨膜瓣是神经受损的因素之一,尤其是在以ANS为中心的30°扇形区域(半径30~40 mm)和以Pog为中心的45°区域(半径20~30 mm),术者翻瓣和牵拉时应警惕IOF和MF的意外损伤。

锥形束CT对83例中国人下颌神经管的位置测量研究

目的:探究下颌神经管与下颌骨的位置关系,为种植及植骨手术提供理论依据。方法:收集83名中国人下颌神经管的锥形束CT扫描数据,对其双侧下颌神经管的数据进行测量分析。结果:下颌神经管到下颌骨颊侧壁的距离为(5.32±1.29)^(7.24±1.29)mm,到下颌骨舌侧壁的平均距离为(3.43±0.99)^(3.93±1.17)mm,到下颌骨下缘的平均距离为(8.81±1.90)^(10.02±2.19)mm,内径的平均值为(2.27±0.44)^(2.61±0.40)mm。男性与女性在下颌管距下颌骨颊侧壁、下颌下缘以及下颌骨内径的平均值上差异有显著性(P<0.05)。前襻的出现率是70.9%,长度为(2.76±1.14)mm。下颌管分支的出现率为10.84%,长度为(10.72±5.29)mm。结论:中国人下颌管在下颌骨内的位置变异较大,前襻和下颌管分支在下颌骨中发生率较高,植骨及种植手术前应仔细检查,减小神经损伤的风险。

颏管的应用解剖学研究

目的 :研究国人颏管的形态及颏管与下颌管、切牙神经管的位置关系 ,为口腔牙种植等颏区手术提供解剖学数据。方法 :磨开 13例 ( 2 6侧 )甲醛溶液固定的湿下颌骨标本的下颌管前段、颏管和切牙神经管始段 ,直接观察测量。另取 2 1侧经过脱钙处理的下颌骨标本 ,解剖并显露下颌管、颏管和切牙神经管进行观测。结果 :下颌管前端分成 2个管 :颏管和切牙神经管。大多数颏管行向后上外开口于颏孔 ,颏管长为 :( 5 .61±1.0 7)mm ,管径为 :( 2 .5 3± 0 .47)mm ,颏孔前缘至下颌管前端的水平距离为 :( 2 .82± 1.2 9)mm ,颏孔下缘到下颌管上缘的垂直距离为 ( 3 .83± 1.43 )mm ,颏管与下颌管之间的角度为 ( 63 .5 7± 13 .71)° ,颏管内有颏神经和颏血管行走。结论 :下颌管向后上外方续为颏管再通向颏孔 ,并非以往认为的下颌管自后上内向前下外方向直接开口于颏孔。

螺旋CT三维成像及曲面断层片对下颌神经管走向的研究

目的通过螺旋CT及曲面断层片探讨下颌神经管与下颌骨的实际位置关系。方法利用螺旋CT扫描机对正常年青人进行下颌骨的横断面连续薄层扫描及多平面重建后,测量并计算下颌神经管在下颌骨中的实际位置及其走行方向。对上述人群拍摄曲面断层片,在曲面断层片上测量并计算下颌神经管在下颌骨中的位置并将两种测量结果进行比较。结果在颊舌方向,下颌神经管总体走行是由舌侧逐渐向颊侧倾斜达颏孔,在走行高度上,在第三磨牙区由上向下走行,自第二磨牙开始下颌神经管逐渐由下向上走行达颏孔。下颌神经管在下颌骨中位置的测量并计算的比值,在两种检测方法中无显著性差异(P<0.05)。结论本研究螺旋CT测量并计算出的比值校正曲面断层片测量并计算的结果,可以在临床工作中指导牙槽外科手术。

64层螺旋CT三维重建观察国人眶上孔、眶下孔、颏孔的位置关系

目的利用64层螺螺旋CT三维重建技术观察国人眶上孔(切迹)、眶下孔、颏孔的位置关系,为临床应用提供影像学依据。方法对92例成年患者行64层螺螺旋CT头部扫描后进行三维重建,重建方法采用容积再现,取冠状位观测眶上孔(切迹)、眶下孔、颏孔的位置关系。测量三孔中心至正中线的距离;在眶上孔(切迹)中心至颏孔中心作一连线(称此连线为S-M线),观察眶下孔中心与S-M线的位置关系。结果眶上孔(切迹)、眶下孔及颏孔中心距颅正中线的距离右侧为:(25.51±2.95)mm、(28.18±2.71)mm、(24.49±2.45)mm;左侧为:(23.33±2.90)mm、(28.20±2.51)mm、(24.96±2.02)mm。眶上孔中心距正中线左右两侧距离差异有统计学意义(P<0.05)。眶下孔中心位于S-M线外侧者164侧例,占89.13%、位于S-M线内侧者12侧例,占6.52%,位于S-M线上的8侧例,占4.35%。结论64层螺旋CT扫描三维重建技术用于观察眶上孔(切迹)、眶下孔、颏孔的位置关系,其结果与颅骨标本观察结果基本一致,且更为准确。

颏管的形态特点及其临床意义

目的 :研究国人颏管的形态与位置 ,为口腔科牙种植术等颏区手术提供解剖学数据。方法 :剖开 6 0侧福尔马林固定的湿下颌骨标本的下颌管前端 ,进行观察测量。结果 :下颌管前端向中线分出一切牙神经管后 ,该管有 96 .7%弯向后上形成颏管再开口于颏孔 ,3.3%直接开口于颏孔 ;颏管长约 ( 4 .0 1±1 .2 0 )mm ,管径约 ( 2 .6± 0 .6 )mm ;颏孔前缘对应下颌管前端的水平距离为 ( 3.54± 0 .70 )mm ,颏孔下缘至下颌管上缘的垂直距离为 ( 3.2 1± 0 .90 )mm ;下牙槽神经在下颌管末端分成两支 ;切牙神经穿切牙神经管分布到切牙 ,颏神经穿颏管出颏孔。结论 :下颌管前端向后上方续为颏管 ,颏管内有颏神经走行。

基于螺旋CT对68例中国人下颌神经管的位置研究

目的:利用64排螺旋CT分析下颌神经管与下颌骨的位置关系。方法:收集68例中国人下颌骨64排螺旋CT扫描的数据,将其导入Simplant软件中,测量下颌神经管的位置。结果:下颌神经管上缘至牙槽嵴顶的平均距离为(15.9±2.5)mm～(18.4±2.3)mm,由后向前逐步增加。下颌神经管下缘至下颌骨下缘的平均距离在颏孔后部区域为(8.7±1.4)mm～(9.0±1.1)mm,在颏孔前部区域距离为(9.9±1.1)mm～(10.9±1.3)mm。颏孔上缘至牙槽嵴顶的平均距离为(13.0±1.8)mm,颏孔下缘至下颌骨下缘的平均距离为(15.5±1.5)mm。颏管的出现率为83.1%,颏管向后、上、外方走行,终止于颏孔。结论:下颌神经管至下颌骨下缘的距离在颏孔后部区域较为恒定,而在颏孔前部区域逐渐增大。中国人颏孔的位置及颏管的长度具有一定的变异性,且颏管的出现率较高。

中国近代人群颏孔、下颌孔位置的变异

目的：对比分析颏孔、下颌孔的水平位置、垂直位置在不同时代间的表现特点及变化。方法：通过对中国新石器时代（55例）、青铜铁器时代（208例）和现代（113例）共376例成年男性下颌骨上颏孔、下颌孔位置的观测、记录，然后用SPSS软件进行数据分析。结果：从新石器时代以来，颏孔的垂直位置在上升。颏孔的水平位置变化为，在新石器-青铜铁器时代体现为前移，在青铜铁器-现代则体现为后移。下颌孔水平位置在新石器-青铜铁器-现代没有明显变化，垂直位置在现代人中较高。结论：颏孔、下颌孔的位置在不同时代人群中有所不同。

基于CBCT对江苏地区人群下颌神经管走向的研究

目的通过锥形束CT（cone beam computed tomography,CBCT）检查分析下颌神经管与下颌骨的位置关系,为避免在外科手术中损伤下牙槽血管神经束提供统计学依据。方法收集90例（男45例,女45例）江苏地区人群（20-79岁）下颌骨的CBCT数据,将其导入NNT 4.6软件中,测量下颌神经管在下颌骨中的位置,分析性别和左右侧对其位置的影响。结果由近中向远中,下颌神经管到牙槽嵴顶的平均距离先增大再减小;到下颌骨颊侧的平均距离逐渐增加;两者在男女间和左右侧间的差异都不显著（P〉0.05）。下颌神经管到下颌骨下缘和舌侧的平均距离逐渐减小,在颏孔后2 mm处两者在左侧的平均距离小于右侧（P〈0.05）,且前者在女性左侧的平均距离小于男性（P〈0.05）。下颌管距下颌后牙牙根的平均距离由近中向远中逐渐减小,两者在男女间和左右侧间的差异都不显著（P〉0.05）。结论江苏地区人群的下颌神经管到牙槽嵴顶和下颌骨颊侧距离男女相似,且左右对称性较好;到下颌骨下缘和舌侧的距离有性别差异,且左右间不太对称;位置在颏孔远中2 mm后相对恒定,在颏孔后2 mm以内的变化较大。

四川籍人群副颏孔的观测分析

目的利用锥形束CT(CBCT)观测四川籍人群副颏孔(AMF)的解剖学数据,为临床颏孔(MF)区种植手术及颏部外科手术等提供解剖学数据。方法调取890例就诊于四川大学华西口腔医院患者的CBCT资料,由一名专业口腔医生对AMF的发生率、直径、同侧MF直径、与同侧MF的直径比例、中心距离、相对位置及与相邻牙的相对位置等进行观察测量。所有数据采用统计学软件SPSS 20.0进行统计学分析。结果四川籍人群AMF的发生率为6.63%,AMF及同侧MF的平均直径分别为(1.65±0.25)mm和(3.84±0.64)mm,AMF与同侧MF的平均直径比例为0.4±0.1,AMF与同侧MF的中心距离平均为(5.45±0.85)mm。AMF与相邻解剖结构的相对位置变异较大,多位于同侧MF的后下位和前上位,第二前磨牙和第一磨牙之间。结论四川籍人群AMF的发生率较高,平均直径为1.65 mm,与同侧MF及相邻牙的相对位置多样。临床进行MF区种植手术及颏部外科手术时应注意AMF的存在。

新石器时代河南淅川下王岗人群颏孔、下颌孔的形态

目的:分析河南淅川下王岗人群下颌骨颏孔、下颌孔的体质形态特点,并探讨相应的时代变异。方法:对44例下颌骨的颏孔、下颌孔形态及位置特点进行分类和记录,然后用SPSS软件进行数据分析。结果:下王岗人群颏孔主要位于第2前磨牙(P4)下方,颏孔大多开口方向为后上,下颌孔水平位置大多位于下颌支中点之后,下颌孔垂直位置大多位于齿槽面之上。结论:下王岗与现生人群相比,颏孔位置有明显的"前移"演化特点。与全新世人群的对比显示,下王岗人群的下颌孔垂直位置稍偏上,水平位置较靠后。考虑到下王岗人群时代较早,下颌骨尺寸很大,似乎提示全新世时期伴随着下颌骨的缩小,下颌孔有"前移"和"下移"的演化趋势。

利用下颌数字成像曲面断层X线片进行下颌管形态研究

目的 :研究下颌骨形态和行径。方法 :利用50例离体下颌骨数字成像曲面断层X线片结合离体下颌骨进行测量。结果 :测得颏孔位置 ,下颌孔位置及下颌管位置和行径。结论 :下颌数字成像曲面断层X线片可较好地反映下颌管位置和行径 。

下颌管的应用解剖学研究

目的 :通过观察和测量下颌骨标本的下颌管 ,了解下颌管的解剖结构。方法 :标本切片是20例40侧新鲜下颌骨标本。结果 :部分标本的颏孔位于下颌第二双尖牙远中。部分的下颌管近中的管壁不完整。结论

乌鲁木齐地区200例成人颏孔区CBCT测量分析

目的:通过观测乌鲁木齐地区200例成人锥形束CT(Cone bean Computer Tomography)图像,获取颏孔区的解剖学数据,为该区域种植手术及外科手术提供参考依据。方法:选取200例于新疆医科大学第一附属医院口腔科就诊患者的CBCT图像,由两名专业的口腔医生对颏孔的位置、大小、颏孔的角度、颏孔上缘到牙槽嵴顶的距离及副颏孔的发生率等进行观测,所得数据导入SPSS17.0进行统计学分析。结果:所有观察对象均显示颏孔,颏孔位置53.5%位于第一第二前磨牙之间,31.3%位于第二前磨牙根方,男性颏孔横径为(3.41±0.54)mm,纵径为(2.72±0.46)mm,女性颏孔横径为(3.11±0.43)mm,纵径为(2.49±0.49)mm,左侧颏孔的平均角度为(45.1±10.05)°,右侧颏孔的平均角度为(43.8±7.9)°,颏孔上缘到牙槽嵴顶的距离(14.19±1.46)mm,副颏孔的发生率7.5%。结论:乌鲁木齐地区成人颏孔位置有差异,副颏孔的发生率较高,在进行该区域手术时,术前应拍摄CBCT进行仔细观测,对减少术中出血、神经损伤等并发症具有一定的指导意义,以确保该区域的手术安全性。

下颌副颏孔的锥形束CT测量分析

目的应用锥形束CT(CBCT)观察副颏孔,分析其发生率、部位及分布规律。方法选取500例(男261例,女239例)CBCT影像回顾性分析。观察副颏孔的发生率及解剖特征,并测量副颏孔直径、颏孔与副颏孔之间距离进行统计分析。结果 500例(1000侧)患者中,39例(7.8%)41侧(4.1%)观察到副颏孔,1例一侧发现2个副颏孔,发生率无性别差异。副颏孔常见于下颌第二前磨牙下方,直径为(1.28±0.42)mm,男性副颏孔直径大于女性,差异有统计学意义(P<0.05)。副颏孔与颏孔之间的距离为(3.36±1.54)mm,与副颏孔直径无相关性。结论经CBCT观察副颏孔有较高的发生率,临床医生在下颌颏孔区进行各种手术应注意这一解剖变异。