健康青年人髁突松质骨结构锥形束CT分析

目的探讨锥形束CT测量下颌骨髁突松质骨结构的可行性，了解下颌骨髁突松质骨结构的分布特点。方法用锥形束CT对40名健康青年志愿者（20～32岁）的80侧下颌骨，获取髁突冠状位正中层面图像，用自行设计的图像分析软件对图像进行二值化处理，并分8区对松质骨结构参数进行分析，包括单位体积内的松质骨体积即骨小梁体积分数、测量范围内骨小梁的平均厚度即骨小梁厚度、单位毫米长度内骨小梁数目及骨小梁间的平均空间距离即小梁分离度。结果髁突上区与中、下区的所有松质骨结构参数值均不同，差异有统计学意义（P〈0．05）；髁突上区骨小梁体积分数最高（52．2％），骨小梁数目最多（1．33mm^-1），骨小梁厚度（393．48μm）和骨小梁分离度（361．59μm）最小；两侧髁突松质骨的结构参数值差异无统计学意义（P〉0．05）。结论下颌骨髁突内部的松质骨结构分布不均，但两侧的分布对称；用锥形束CT结合图像分析技术可以实现髁突松质骨结构的体内定量分析。     

不同骨型人群髁突不对称性的锥形束CT评价

目的 利用锥形束CT（cone-beam CT, CBCT）评价不同骨型人群中的髁突不对称性。方法 收集拍摄CBCT的个体共110名,年龄18~30岁。对CBCT数据进行三维重建、建立参考系并三维定点。所有个体按照不同骨型进行分组,组Ⅰ（Cl Ⅰ）为骨性Ⅰ类（0°≤ANB≤5°）,组Ⅱ（Cl Ⅱ）为骨性Ⅱ类（ANB>5°）,组Ⅲ（Cl Ⅲ）为骨性Ⅲ类（ANB<0°）,每组按性别进一步分组。输出定点坐标,计算髁突（Co-Sig）的不对称情况,同时分析下颌支（Go-Sig）以及髁突-下颌支（Co-Go）的对称性。采用SPSS 17.0软件包对数据进行统计学分析。结果 组Ⅱ和组Ⅲ间的髁突-下颌支不对称性（Co-Go R-L）具有统计学差异（P<0.05）,差异在三维上主要体现在y坐标（P<0.05）;组Ⅰ和组Ⅲ以及组Ⅱ和组Ⅲ间的下颌支不对称性（Go-Sig R-L）也受不同骨型影响,具有统计学差异（P<0.05）,差异在三维上同样体现在y坐标（P<0.05）。左右侧髁突、下颌支以及髁突-下颌支在部分人群中体现出性别差异及偏侧性差异（P<0.05）,且这种偏侧性均表现为右侧优势。颏下点（Me）的z坐标在不同骨型人群中的差异较大（P<0.05）,而x和y坐标无统计学差异（P>0.05）。结论 髁突-下颌支以及下颌支的不对称性与不同人群的骨型相关,差异主要来源于高度。骨性Ⅲ类和Ⅱ类人群分别表现为下颌骨前突和下颌骨后缩。颏部偏斜与髁突不对称性的关系需要进一步探讨。     

不同矢状骨面型髁突位置的锥形束CT对比研究

目的 比较骨性Ⅰ类和骨性Ⅱ类受试者的髁突位置,为临床诊断与治疗提供指导。方法 选择50例骨性Ⅰ类受试者（A组,男 27例,女 23例,年龄 18~30岁,平均年龄26岁）和50例骨性Ⅱ类受试者（B组,男 24例,女 26例,年龄 18~28岁,平均年龄 25岁）。两组均拍摄锥形束 CT（CBCT）并应用相应软件进行测量分析,测量髁突位置相关测量项目。所有数据采用 SPSS 19.0统计学软件进行统计分析。结果 A组和 B组双侧髁突位置测量值差异无统计学意义（P>0.05）; A组前后间隙与 B组相比较,差异有统计学意义（P<0.05）; A组前后间隙比较 B组大,差异有统计学意义（P<0.05）。结论 骨性Ⅱ类受试者相对骨性Ⅰ类受试者髁突位置为居中位偏后。     

维吾尔族错(牙合)畸形患者髁突位置及颞下颌关节形态的锥形束CT研究

目的:运用锥形束CT(CBCT)探讨维吾尔族错(牙合)畸形成年患者髁突位置及颞下颌关节形态特征及其差异,为临床诊治提供依据.方法:对64例维吾尔族安氏Ⅰ类和安氏Ⅱ类1分类错(牙合)畸形成年患者的颞下颌关节CBCT图像进行分析测量,采用SPSS17.0软件包对颞下颌关节窝间隙、髁突相关指标进行统计学分析,比较安氏Ⅰ类和安氏Ⅱ类1分类颞下颌关节形态之间的差异.结果:安氏Ⅰ类和安氏Ⅱ类1分类成年维吾尔族患者髁突在颞下颌关节窝内的位置无性别差异(P＞0.05);安氏Ⅱ类1分类患者的颞下颌关节窝前间隙、上间隙及深度均大于安氏Ⅰ类患者,后间隙小于安氏Ⅰ类患者;髁突的内外径及前后径在不同矢状骨面型患者中存在显著差异.结论:维吾尔族安氏Ⅰ类患者的髁突位置及颞下颌关节形态与安氏Ⅱ类1分类患者存在差异,临床诊治过程中应予以重视.     

单侧后牙长期缺失后髁突形态的锥形束CT研究

目的采用锥形束CT（CBCT）研究单侧后牙长期游离缺失对双侧髁突形态的影响。方法收集30例单侧后牙长期游离缺失患者和30例正常对照者的CBCT图像,应用Mimics 15.0软件测量双侧髁突体积、面积、线距及骨密度,对测量结果进行统计学分析。结果缺牙侧的髁突体积、髁顶体积及其骨密度明显小于非缺牙侧（P<0.05）;髁突横截平面的面积及其骨密度大于非缺牙侧（P<0.05）。结论单侧后牙长期游离缺失后,双侧髁突均发生适应性改建,缺牙侧髁突小于非缺牙侧。     

特发f生髁突吸收的颞下颌关节锥形束CT分析

目的利用特发性髁突吸收（ICR）患者的锥形束CT（CBCT）资料,探讨其颞下颌关节的变化。方法对39例ICR患者及28例正常人行颞下颌关节的CBCT扫描,测量颞下颌关节结构的各相关指标,并进行统计学分析。结果 ICR组与正常组间髁突内外径、前后径、水平角、关节结节斜度、关节上间隙等测量指标之间的差异均有统计学意义（P＝0.000）,表现为ICR组的髁突内外径、前后径、结节斜度、关节上间隙等减小,水平角则增大。结论 ICR的影像学主要表现是髁突的变小、前斜面的吸收、结节斜度的降低,同时髁突有往前内旋转和往上移动的趋势,这些指标可用来评估ICR的进展、疗效及预后。     

前牙开患者颞下颌关节间隙及髁突形态的锥形束CT评价

目的 应用锥形束CT(cone-beam CT,CBCT)对前牙开患者的颞下颌关节间隙及髁突形态进行测量分析,探讨前牙开患者与正常覆患者的颞下颌关节的差异.方法 选取2014年6月至2020年8月于南京大学医学院附属口腔医院正畸科就诊的前牙开患者54例(前牙开组)和正常覆患者54例(正常覆组),对其拍摄的颌面部CBCT...     

基于锥形束CT分析骨性Ⅲ类高角伴下颌偏斜患者髁突形态和位置的研究

目的 应用锥形束CT（CBCT）对比分析骨性Ⅲ类高角伴下颌偏斜患者与个别正常牙合患者髁突的形态和位置。方法 选取2017年9月至2019年9月于上海交通大学医学院附属第九人民医院口腔正畸科就诊的患者40例,其中骨性Ⅲ类高角伴下颌偏斜患者20例（偏斜组）,个别正常牙合患者20例（对照组）。所有患者于治疗前拍摄CBCT,使用Invivo 5.0软件对CBCT影像进行三维重建及测量,并比较两组患者两侧髁突形态和位置的差异。结果 （1）偏斜组患者两侧髁突形态和位置指标测量值比较发现,在髁突形态方面,偏斜侧髁突最大轴面面积、髁突高度、髁顶高度均比非偏斜侧小,差异均有统计学意义（均P < 0.05）。在髁突位置方面,偏斜侧髁突外间隙、上间隙和后间隙比非偏斜侧小;偏斜侧髁突前间隙、内间隙及髁突外突距比非偏斜侧大,差异均有统计学意义（均P < 0.05）。（2）对照组两侧髁突形态和位置指标测量值比较,差异均无统计学意义（均P > 0.05）。（3）偏斜组两侧髁突形态和位置指标测量值分别与对照组比较发现,在髁突形态方面,偏斜组偏斜侧髁突高度比对照组大,最大轴面面积比对照组小;非偏斜侧髁突高度大于对照组,差异均有统计学意义（均P < 0.05）。在髁突位置方面,偏斜组偏斜侧髁突上间隙小于对照组,髁突内间隙、前间隙、髁突外突距及髁突与正中矢状面距大于对照组,差异均有统计学意义（均P < 0.05）。结论 骨性Ⅲ类高角伴下颌偏斜患者双侧髁突的形态和位置具有明显的不对称性,偏斜侧髁突形态较对侧小,并向后上外方向移位。骨性Ⅲ类高角伴下颌偏斜患者的髁突高度比个别正常牙合患者大。     

颞下颌关节髁突囊样变的锥形束CT影像特点

目的 利用口腔颌面锥形束CT观察髁突囊样变的影像学表现,探讨囊样变的影像特点并加以分类。方法 收集颞下颌关节锥形束CT影像学表现有囊样变的194例患者,观察并记录囊样变的部位、大小、数量、边缘骨白线、周围骨小梁结构、髁突整体骨质情况。根据髁突整体骨质情况,将髁突囊样变分为Ⅰ型和Ⅱ型,比较其发生的部位、数量、边缘骨白线以及周围骨小梁结构情况。结果 194例患者的198侧关节发现囊样变表现,94例位于左侧关节,96例位于右侧关节,4例位于双侧关节。50.0%（99侧）的囊样变位于髁突前外侧皮质骨下方;囊样变直径最小1.2 mm,最大13.5 mm,平均（3.4±1.5）mm;75.3%（149侧）为单发囊样变;62.6%（124侧）存在完整的骨白线包绕;80.8%（160侧）周围骨小梁结构有骨质硬化。66.7%（132侧）囊样变髁突表现有晚期骨关节病征象,5.1%（10侧）囊样变髁突表现有早期骨关节病征象,28.3%（56侧）髁突除囊样变外无其他明显骨质改变。Ⅰ型和Ⅱ型髁突囊样变在发生部位、数量和周围骨小梁结构方面存在差异,Ⅰ型髁突囊样变较多发和骨质硬化,Ⅱ型髁突囊样变发生于髁突内部或髁突颈部较多。结论 Ⅰ型和Ⅱ型髁突囊样变在发生部位、数量和周围骨小梁结构存在不同,这可能与其病因及形成机制不同有关。     

磨牙症患者颞下颌关节结构的锥形束CT测量分析研究

目的:了解磨牙症患者的颞下颌关节三维位置并分析变化特征。方法:对45例口腔门诊磨牙症患者的病例资料、其颞下颌关节锥形束CT图像中关节间隙及位置进行定量测量研究,并进行统计分析和评价。结果:获得了不同三维层面关节间隙及位置的测量值。矢状方向分析:90侧关节,30.5%处于后位,27.8%处于前位;冠状方向:双侧关节近中、冠中、远中间隙测量结果对应比较,差异均无统计学意义(P>0.05);水平方向:左右侧髁突角度比较无统计学差异(P>0.05)。结论:磨牙症患者对TMJ结构位置产生影响,在矢状位方向存在髁突非中性移位。     

咬合板高度对下颌髁突位置的影响

目的:探讨咬合板高度对髁突位置的影响。方法:观察戴咬合板前及分别戴3、5和7mm厚度的稳定性咬合板后髁突位置的变化。结果:戴入咬合板后髁突向前下方移位,其移动距离随着咬合板厚度增加而加大。无论是否戴咬合板,下颌从ICP轻接触至紧咬的过程中,髁突均向前上方向移动;戴7mm厚度咬合板,其髁突移动距离(右侧髁突在前后及上下方向、左侧髁突在前后方向)及切点的上下方向位移均显著大于戴3mm厚度咬合板,而与戴5mm厚度咬合板相比较髁突及切点位移无显著性差异。叩齿运动总循环时间的变异系数戴7mm咬合板时显著大于其他。结论:7mm厚度咬合板对髁突位置的影响显著大于3mm咬合板但与5mm咬合板无明显差异     

Posterior occlusal support and bite force influence on the mandibular position

Three-dimensional mandibular displacement related to loss of posterior occlusal support was investigated. Five subjects, whose mandibular premolars and molars needed to be restored, were selected. Their experimental prostheses were removed in sequence from the most posterior to anterior. The more the absence of posterior occlusal support increased, the more condylar displacements were increased. On the other hand, maximum bite forces were decreased, by removing each prosthesis in sequence from posterior to anterior. These results suggest that condylar position would be easily displaced with low level bite force following loss of posterior occlusal support.     

Relationship between the TMJ disc and condyle position on MRI and occlusal contacts on lateral excursions in TMD patients

Confusion about the relationship between dental occlusion and the temporomandibular disorders (TMD) has been evident in the literature for many years. Previous studies have supported the concept of a multifactorial aetiology of TMD, the occlusal factor in general being of minor importance. The purpose of the study was to investigate the relationship between condyle and disc positions and occlusal contacts on lateral excursions of the mandible in patients with TMD. A total of 122 temporomandibular joints (TMJs) of 61 patients with TMD were evaluated using magnetic resonance imaging (MRI) and occlusal analyses were made clinically. Non-working-side contacts were found to be statistically significant in TMJ anterior disc displacement. No significant statistical correlation was found between the severity of anterior disc displacement and non-working-side contacts in both canine guidance and group function occlusions. There was no correlation between non-working-side contacts and condyle positions in both occlusion types in the present study. It was concluded that non-working-side contacts had some effect on disc position in TMD, however the presence of these contacts in both canine guidance and group function occlusions did not correlate with anterior disc displacement in TMD statistically. Therefore, non-working-side contacts are not to be regarded as the prime cause of anterior disc displacement.     

(牙合)垫治疗低位咬合的髁突位置变化研究

目的:观察垫治疗低位咬合的疗效.方法:对因严重磨损、伴颞下颌关节紊乱症状的低位咬合患者13例,用(牙合)垫恢复其正常垂直距离.于戴用(牙合)股垫前、后及戴用后半年,摄双侧闭口薛氏位片,行关节间隙的测量,并作统计学处理.结果:戴用(牙合)垫后关日前间隙减少单资2.07mm,后间隙及上间隙分别增加1.11mm、0.51mm,有显著性差异 半年复查结果与戴用(牙合)垫后相比,关节间隙改变则无显著性差异(P>0.05).结论:(牙合)垫通过恢复正常的垂直距离,使髁突向前下移位,并稳定于关节内位置正常,恢复了牙、肌肉、关节的协调关系.     

Effect of non-working occlusal contacts on vertical condyle position

Summary  The presence of non-working occlusal contacts is often considered harmful for the temporomandibular joint. Thus, the purpose of this study was to investigate the effect of non-working occlusal contacts on the condylar position during submaximal and maximal clenching. The study comprised 22 healthy subjects having a canine-guided occlusion. None of them had a third molar and none of them had a missing tooth or showed tooth mobility. All subjects clenched on (i) the canine, (ii) the canine while a stiff bite registration material was positioned between the second premolar and the first molar on the non-working side. The clenching level was controlled by surface electromyography of the masseter muscle. During clenching, the vertical and horizontal condylar position was predicted using six degrees of freedom ultrasonic motion analyser. Clenching on the canine caused a cranial movement of the non-working side condyle. This movement was reduced by 0·6–0·9 mm when the subjects clenched while the artificial non-working side contacts were in place. These results indicate that the contacts on the non-working side may be able to prevent upward joint movement.     

Osteochondroma of the mandibular condyle: surgical excision followed by occlusal stabilization

Osteochondroma of the mandibular condyle in adults can be treated by surgical excision, condylectomy followed by costochondral graft or orthognathic surgery. Such complex treatment plan may not be appropriate for patients with old age, affected with chronic osteochondroma of the condyle. In this clinical report, we present a patient with osteochondroma of the condyle treated by surgical excision. The patient's postoperative occlusion was a contraindication for orthognathic surgery because of the severe abrasion of the teeth and the chronic compensation of the dentition to the deviated mandible. Surgical excision of the lesion was carried out under general anesthesia, and the remaining condylar head was salvaged as much as possible. No graft materials or posthodontic condyle reconstruction was carried out. Because there was no occlusal stop to secure the mandible in a centric relation position of the condyle, a stabilization splint was delivered to position the condyle in a relatively stable position. The stability of the condyle position was evaluated by follow-up cone beam computed tomographic scans of the pathologic and the contralateral condyle, along with clinical factors such as occlusal contact points and mandible movements assayed by ARCUSdigma (KaVo). After significant condylar position was achieved, full prosthodontic reconstruction was performed to both the patient's and the dentist's satisfaction.     

The anatomical relationship between the position of the auriculotemporal nerve and mandibular condyle

Head, neck, face, and ear pains are commonly associated with disorders of the temporomandibular joint (TMJ). Several theories have been proposed regarding the functional relationship of the TMJ and the associated structures, and how they might contribute to certain painful conditions. This study was conducted to determine the anatomic relationship of the auriculotemporal nerve to the middle meningeal artery and the mandibular condyle. Forty human cadaver temporomandibular joints were dissected to locate the precise position of the auriculotemporal nerve to the mandibular condyle. The study findings revealed a significant variation in the relationship of the auriculotemporal nerve to the middle meningeal artery. The auriculotemporal nerve was found to be between 10-13 mm inferior to the superior surface of the condyle and 1-2 mm posterior to the neck of the condyle. The nerve was not found to be in a position that would likely create an entrapment with adjacent tissues. These findings may assist the clinician to locate the most appropriate injection site for an auriculotemporal nerve block.