The relationship between temporomandibular joint disc morphology and stress angulation in skeletal Class III patients

The aim of this study was to examine the relationship between disc position and stress direction on the condyle by means of stress analysis using the rigid body spring model (RBSM) theory. The material consisted of 88 joints of 44 Class III dentofacial deformity patients, divided into symmetry and asymmetry groups on the basis of the Mx-Md midline position. The asymmetry group was identified by comparison with a reference midline vertical plane passing through a plane from ANS to Me. Asymmetry was diagnosed when the angle between these two planes was greater than 3 degrees. The geometry of the stress analysis model was based on sagittal tomography of the subject. The first molar, gonial angle, and the most anterior, superior, and posterior points on the condyle were plotted on a computer display, and stress angulation on the condyles was calculated with the RBSM program. In addition to anterior displacement with or without reduction, three types of disc position could be identified using magnetic resonance imaging (MRI): anterior, fully covered and posterior. In the asymmetric group, stress angulation was significantly higher (P < 0.05) at the deviation side compared with the non-deviation side. There was also a significant correlation between disc position and stress angulation (P < 0.05). In the asymmetry group, regression analysis indicated a significant correlation (P < 0.001) between the difference in stress angulation (between the deviation side and the non-deviation side) and the degree of asymmetry (measured by the angle of asymmetry). This study demonstrated that temporomandibular joint (TMJ) stress was associated with TMJ morphology in Class III patients whether or not they were asymmetric.     

Incidence of anterior disc displacement without reduction of the temporomandibular joint in patients with dentofacial deformity

The aim of this study was to investigate the incidence of anterior disc displacement without reduction (ADDwoR) of the temporomandibular joint (TMJ) in patients with dentofacial deformity. Eighty-eight female patients (176 joints) with skeletal class III malocclusion and 33 female patients (66 joints) with skeletal class II malocclusion, with or without anterior open bite and asymmetry, were evaluated. Magnetic resonance imaging (MRI) of the TMJ was used to diagnose ADDwoR. A statistical analysis was performed to examine the relationship between ADDwoR and skeletal structure. ADDwoR was present in 37 of the 66 joints (56.1%) in class II compared to 34 of the 176 joints (19.3%) in class III (P < 0.05). In class III, ADDwoR was significantly more common in joints with mandibular asymmetry (24/74; 32.4%) than in joints with open bite (9/62; 14.5%) and joints with open bite and without mandibular asymmetry (1/38; 2.6%). In class II, ADDwoR was significantly less common in joints with mandibular asymmetry and without open bite (1/8; 12.5%). ADDwoR was only observed on the deviated side in both class III and class II with mandibular asymmetry. The prevalence of ADDwoR differed according to the dentofacial morphology.     

Temporomandibular joint symptoms and disc displacement in patients with mandibular prognathism

Our objective was to find out the incidence of signs and symptoms of temporomandibular joint (TMJ) and disc displacement in patients with mandibular prognathism. Fifty-one patients were examined clinically and by axial computed tomography(CT). The incidence of TMJ signs and symptoms was 6/25(24%) in patients with simple mandibular prognathism and 12/26(46%) in patients with mandibular prognathism and asymmetry. No discs were displaced in patients with simple mandibular prognathism, but 15(58%) of the patients with mandibular prognathism and asymmetry had displaced discs. There was no association between signs and symptoms of TMJ and disc displacement. Patients with mild protrusion and severe asymmetry of the mandible had a high incidence of disc displacement, which interestingly was on the deviated side in 14 of the 15 patients affected. We conclude that skeletal morphology may have a role in the development of TMJ disorders but the mechanism is obscure.     

Comparison of the clinical outcomes of patients having sounds in the temporomandibular joint with skeletal mandibular deformities treated by vertico-sagittal ramus osteotomy or vertical ramus osteotomy

OBJECTIVE: This article describes the effects of the intraoral vertico-sagittal ramus osteotomy (IVSRO) procedure on the jaw of patients with temporomandibular joint (TMJ) disorders. STUDY DESIGN: IVSRO was performed on 15 patients (30 sides) who had mandibular protrusion or asymmetry with TMJ dysfunction. IVRO was performed on another 15 patients (30 sides). All of the 30 patients had sounds in the TMJ uni- or bilaterally. The relative positions of the condyle and disc and the range of motion of the condyles were determined by magnetic resonance imaging (MRI) before and 12 months after the operations. RESULTS: Sounds such as clicking improved in 92% (24/26) of the joints in the IVSRO group, and in 83% (20/24) of the joints in the IVRO group 12 months after the operation. The positional relationship between the condyle and disc on the MR images improved in 82% (9/11) of the joints with reduction of the anterior disc displacement; in 60% (3/5) of the joints without reduction of the anterior disc displacement in the IVSRO group; in 75% (9/12) of the joints with reduction of the anterior disc displacement; and in 40% (2/5) of the joints without reduction of the anterior disc displacement in the IVRO group. Immediately after the operation, the condyle was displaced anterio-inferiorly in all joints in both groups, but gradually returned to close to the preoperative position. There were no significant differences between the 2 groups regarding the extent of shift of the condylar head at 2 weeks and 12 months after the operation. CONCLUSION: The clinical outcomes of the IVSRO procedure are similar to those of the IVRO procedure. Therefore, IVSRO may be a suitable procedure for patients having TMJ dysfunction with skeletal mandibular deformities, particularly when an IVRO is unsuitable.     

颞下颌关节盘前移位患者关节骨形态与矢状向关节盘位置的关系

目的　利用磁共振成像（MRI）技术和锥形束CT（CBCT）分析颞下颌关节盘前移位患者矢状向关节盘位置与关节骨形态的关系。方法　对97例患者的178个颞下颌关节（TMJ）进行回顾性分析，根据矢状向MRI上关节盘的位置分成4组，即对照组（关节盘无移位）、轻度组（关节盘轻度前移位）、中度组（关节盘中度前移位）和重度组（关节盘重度前移位）。然后利用Mimics 20软件基于CBCT数据进行TMJ的相关形态学参数测量，包括髁突线性尺寸（宽度、长度和高度）、髁突体积和表面积，关节窝的深度和长度，关节结节倾斜角，关节前、上、后间隙等，并对各组矢状髁突位置进行评估。使用方差分析、非参数检验和卡方检验等比较关节形态及位置参数的组间差异，采用相关性分析探索矢状关节盘位置与关节测量参数之间的相关性。结果　髁突的线性尺寸、关节窝深度、关节倾斜角、关节间隙和矢状髁突位置分布在4组间差异有统计学意义，而关节窝长度在4组间差异没有统计学意义；相关性分析显示：髁突的线性尺寸、髁突的体积及表面积、关节窝的深度、关节结节倾斜角和关节上间隙与关节盘矢状位置之间存在显著负相关，而关节后间隙与矢状关节盘位置之间存在显著正相关。结论　TMJ骨形态与不同矢状关节盘位置之间存在相关性，应警惕临床看到的关节骨形态的退行性改变可能是患者存在关节盘前移位的标志。     

Changes in temporomandibular joint and ramus after sagittal split ramus osteotomy in mandibular prognathism patients with and without asymmetry

The purpose of this study was to examine the changes in the temporomandibular joint (TMJ) and ramus after sagittal split ramus osteotomy (SSRO) with and without Le Fort I osteotomy.The subjects consisted of 87 Japanese patients diagnosed with mandibular prognathism with and without asymmetry. They were divided into 2 groups (42 symmetric patients and 45 asymmetric patients). The TMJ disc tissue was assessed by magnetic resonance imaging (MRI) and the TMJ space, condylar and ramus angle were assessed by computed tomography (CT) preoperatively and postoperatively.Medial joint space on the deviation side in the asymmetry group was significantly larger than that in the symmetry group (P = 0.0043), and coronal ramus angle on the non-deviation side in the asymmetry group was significantly larger than that in the symmetry group preoperatively (P = 0.0240). The horizontal condylar angle on the deviation side in the asymmetry group was significantly larger than that in the symmetry group (P = 0.0302), posterior joint space on the non-deviation side in the symmetry group was significantly larger than that in the asymmetry group postoperatively (P = 0.00391).The postoperative anterior joint space was significantly larger than the preoperative value on both sides in both groups (the deviation side in the symmetry group: P = 0.0016, the non-deviation side in the symmetry group: P < 0.0001, the deviation side in the asymmetry group: P = 0.0040, the non-deviation side in the asymmetry group: P = 0.0024). The preoperative disc position could was not changed in either group.These results suggest that significant expansion of anterior joint space could occur on the deviation side and non-deviation side in the asymmetry group as well as on both sides in the symmetry group, although disc position did not change in either group.     

颞下颌关节内紊乱与关节疼痛关系的研究

目的 :探讨TMJ疼痛与TMJID的关系。方法 :对 4 4例单侧关节疼痛TMD患者 88侧关节完成开闭口斜矢状位PDW成像 ,以非疼痛侧盘突关系做自身对照 ,评价关节疼痛与TMJID的关系。结果 :4 4个疼痛关节中 ,30个关节 (6 8.2 % )表现为TMJID ,其中ADDR为 11个关节 (2 5 % ) ,ADDWR为 19个关节 (4 3.2 % ) ;而 4 4个非疼痛关节中 6个关节 (13.6 % )表现为ADDR。经统计学分析 ,TMJ疼痛与TMJID及TMJID的类型有显著相关性 (P <0 .0 0 5 )。结论 :TMJID是颞下颌关节疼痛的原因之一     

Morphological differences in the temporomandibular joints in asymmetrical prognathism patients

OBJECTIVE: To investigate the morphology of the temporomandibular joints (TMJ) in skeletal asymmetry with prognathism. DESIGN: Three-group observational clinical study. SETTING AND SAMPLE POPULATION: University setting. Thirty-five patients undergoing orthognathic surgery without signs and symptoms of TMJ disorder were assigned to three groups (right deviation, n = 11; left deviation, n = 14; and non-deviation; n = 10) based on anteroposterior cephalometric analysis. OUTCOME MEASURE: Positional and morphological differences of the TMJs were evaluated using a total of 70 bilateral sagittal TMJ magnetic resonance images. RESULTS: In both the right and left deviation groups, the TMJ on the deviated side showed a significantly steeper eminence than that on the non-deviated side (p < 0.05). The anterior joint space was narrower on the deviated side than on the non-deviated side whereas the posterior joint space did not differ markedly, indicating an anterior position of the condyle in the glenoid fossa of the TMJ on the deviated side. Disk displacement comparisons revealed no significant differences between left and right sides in the symmetry or asymmetry group. CONCLUSION: Asymmetrical prognathism patients exhibit significant morphological differences between the right and left TMJs concerning the slope of the articular eminence, which correspond to facial asymmetry.     

MRI评价颞下颌关节镜盘复位固定术的短期疗效

目的:用MRI评价颞下颌关节(temporomandibular joint,TMJ)镜关节盘复位固定术的短期疗效。方法:2004- 08—2007-03期间,共对639例(764侧关节)Ⅱ～Ⅴ期TMJ结构紊乱(internal derangement,ID)患者进行了关节镜治疗,所有患者手术前及术后1～7 d进行MRI检查。根据我们制定的成功标准,在髁突矢状位上选用内、中、外3个不同的层面进行手术前后关节盘的位置比较,从而评价手术疗效。标准制定如下:若3个层面完全复位,则疗效定为"优";2个层面完全复位,则疗效定为"良";仅1个层面或完全未复位则疗效定为"差"。将"优"和"良"定为有效(注:若术前仅有1个或2个1/3层面移位者,要求均被复位才算有效)。结果:764侧关节中,术后MRI显示729侧关节为"优",占95.42%;24侧关节为"良",占3.14%;11侧关节为"差",约1.44%,对评价为"差"的关节进行了二次关节镜手术或开放性手术。结论:经手术前后MRI对比验证,颞下颌关节镜关节盘复位固定术能有效地将关节盘复位,但其稳定性尚需进一步评价。     

Preservation of disc for treatment of traumatic temporomandibular joint ankylosis.

PURPOSE: A new operating method was used to treat traumatic temporomandibular joint (TMJ) ankylosis, to restore the structure of the TMJ, to improve the secondary maxillofacial deformity, and prevent recurrence of TMJ ankylosis. PATIENTS AND METHODS: Thirty-six patients (20 females, 16 males; aged 5 to 54 years old) with TMJ ankylosis type II or III of 1 to 16 years' duration, with a maximal mouth opening from 0 to 15 mm preoperatively participated. The new method was to separate bony fusion between condyle and glenoid fossa, remove the condylar fragment that displaced medially or anteroinferiorly, mobilize the remains of the disc over the condylar stump and suture it with articular capsule, and shave the surface of the condylar stump and glenoid fossa smooth. RESULTS: Follow-up was performed from 1 to 7 years postoperatively in 21 cases. No recurrences occurred in patients whose TMJ disc was retained during operation. Patients had an average maximal mouth opening of 33.7 mm postoperatively. An 11-year-old patient showed an improved facial symmetry after surgery. CONCLUSION: By restoring the normal structure of the TMJ and preservation of the disc, recurrence of traumatic TMJ ankylosis and facial deformity in younger patients can be prevented.     

兔颞下颌关节盘移位与骨关节病关系的评价

目的评价颞下颌关节盘移位与骨关节病的关系。方法通过手术方法将２５只大耳白兔的颞下颌关节盘前移，术后１、２、４、８、１２周进行组织病理学检查。结果１１侧手术关节为部分关节盘前移位，８侧为完全性关节盘前移位，６侧为关节盘穿孔。部分关节盘前移位出现早期退行性改变和后期生理性改建，完全性关节盘前移位和关节盘穿孔出现退行性改变和严重的骨关节病。结论颞下颌关节盘前移位的程度与骨关节病有关，关节盘前移位越明显，越易出现骨关节病     

山羊颞下颌关节强直病理模型的建立

目的：建立山羊颞下颌关节强直病理模型,以进一步探讨颞下颌关节强直的病因。方法：取山羊9只,随机等分为3组。分别采用破坏关节表面软骨、破坏关节表面软骨＋去除关节盘、破坏关节表面软骨＋去除关节盘＋关节腔内植骨3种不同手段制作模型。术后3个月后观察颞下颌关节强直的形成情况。结果：关节软骨破坏＋去除关节盘组全部发生强直;保留关节盘者无一例发生强直;植骨组仅2只山羊发生关节黏连。强直者,光镜下表现为髁突与关节窝间类骨质形成;未强直者。光镜下表现为关节表面破坏。结论：去除关节盘＋关节软骨破坏形成的TMJ强直,具有可重复性、短期内发生以及良好的相似性,接近人类病变发生的过程．是一种较好的制作颞下颌关节强直模型方法。     

兔颞下颌关节盘前移位的X线研究

目的　通过影像学检查了解颞下颌关节盘前移位的病理变化过程,证实关节盘前移位与退行性改变之间的关系。方法　在手术组动物一侧关节区显露颞骨颧突根部,用丝线垂直穿过关节盘前带的延伸部并拉缝线向前并固定,使颞下颌关节盘前移位。手术对照组的手术步骤与手术组相同,但不缝合关节盘前带的延伸部,也不将关节盘位向前方。正常对照组5只,手术组和手术对照组动物术后1、2、4、8、10、12和16周分别处死。拍摄关节X线片,观察38只兔颞下颌关节X线表现。将兔左、右关节区锯成组织块,肉眼观察兔关节盘的位置。结果　手术组关节盘位置与形态均发生了改变,13侧为部分关节盘前移位,完全性关节盘前移位为11侧,关节盘穿孔为9侧。部分关节盘前移位出现关节间隙狭窄或消失,髁状突骨密度增高。完全性关节盘前移位与关节盘穿孔表现为髁状突骨质增生、破坏及肥大,关节结节磨平以及硬化。结论　颞下颌关节盘前移位可导致关节骨质改变。完全性关节盘前移位和关节盘穿孔与骨关节病的关系密切。     

成人高角骨性Ⅲ类错[牙合]颞下颌关节锥体束CT测量分析

目的：应用锥形束CT（CBCT）,分析成人高角骨性Ⅲ类颞下颌关节（TMJ）的骨性结构。方法：分别对30名成人高角骨性Ⅲ类患者和30名成人正常聆在牙尖交错位进行CBCT扫描,使用Ez3D2009软件对重建影像进行比较分析。结果：Ⅲ类高角组中,双侧TMJ形态无显著统计学差异;与正常组相比,Ⅲ类高角组TMJ骨性结构具有显著的统计学差异（P〈O．01）。结论：成人高角骨性Ⅲ类双侧TMJ结构基本对称;Ⅲ类高角组髁突在关节凹中的位置更为靠前;Ⅲ类高角组TMJ的骨性结构与正常组相比有显著不同。     

Condylar and disc positions after intraoral vertical ramus osteotomy with and without a Le Fort I osteotomy

The purpose of this study was to examine the changes in temporomandibular joint (TMJ) morphology and clinical symptoms after intraoral vertical ramus osteotomy (IVRO) with and without a Le Fort I osteotomy. Of 50 Japanese patients with mandibular prognathism with mandibular and bimaxillary asymmetry, 25 underwent IVRO and 25 underwent IVRO in combination with a Le Fort I osteotomy. The TMJ symptoms and joint morphology, including disc tissue, were assessed preoperatively and postoperatively by magnetic resonance imaging and axial cephalogram. Improvement was seen in just 50% of joints with anterior disc displacement (ADD) that received IVRO and 52% of those that received IVRO with Le Fort I osteotomy. Fewer or no TMJ symptoms were reported postoperatively in 97% of the joints that received IVRO and 90% that received IVRO with Le Fort I osteotomy. Postoperatively, there were significant condylar position changes and horizontal changes in the condylar long axis on both sides in the two groups. There were no significant differences between improved ADD and unimproved ADD in condylar position change and the angle of the condylar long axis, although distinctive postoperative condylar sag was seen. These results suggest that IVRO with or without Le Fort I osteotomy can improve ADD and TMJ symptoms along with condylar position and angle, but it is difficult to predict the amount of improvement in ADD.     

Preservation of condyle and disc in the surgical treatment of type III temporomandibular joint ankylosis: a long-term follow-up clinical study of 111 joints

The purpose of this study was to establish the role of retaining the condyle and disc in the treatment of type III ankylosis, by clinical and computed tomography (CT) evaluation. A total of 90 patients with type III ankylosis met the inclusion criteria; 42 patients had left temporomandibular joint (TMJ) ankylosis, 27 patients had right TMJ ankylosis, and 21 had bilateral TMJ ankylosis, thus a total 111 joints were treated. Considerable improvements in mandibular movement and maximum mouth opening were noted in all patients. At the end of a minimum follow-up of 2 years, the mean inter-incisal mouth opening was 30.7 mm. Postoperative occlusion was normal in all patients, and open bite did not occur in any case because the ramus height was maintained through preservation of the pseudo-joint. Only three patients had recurrence of ankylosis, which was due to a lack of postoperative physiotherapy. The advantages of condyle and disc preservation in type III ankylosis are: (1) surgery is relatively safe; (2) the disc helps to prevent recurrence of ankylosis; (3) the existing ramus height is maintained; (4) the growth site is preserved; and (5) there is no need to reconstruct the joint with autogenous or alloplastic material. It is recommended that the disc and condyle are preserved in type III TMJ ankylosis.     

Management of temporomandibular joint ankylosis type III: lateral arthroplasty as a treatment of choice

Many surgical techniques for the management of temporomandibular joint (TMJ) ankylosis have been described in the literature. The purpose of this study was to report our experience using a lateral arthroplasty technique in the management of type III ankylosis. The records of 15 patients treated for TMJ ankylosis at our institution between 2007 and 2011 were reviewed. Pre- and postoperative information collected included age, gender, aetiology, ankylosis type/classification, existing facial asymmetry, maximum pre- and postoperative mouth opening, complications, and recurrence of ankylosis. The mean maximum inter-incisal opening in the preoperative period was 12.9 mm and in the postoperative period was 36.2 mm. No major complication was observed in any patient. No recurrence was noted in any patient. Our working hypothesis was that for patients with ankylosis type III, the medially displaced condyle and disc can fulfil their role in mandibular function and growth after extirpation of the ankylozed mass. Although they are located in an awkward medial position, they should function exactly as they would after a properly treated, displaced condylar fracture.     

Outcomes of anterior disc displacement and condylar remodelling for sagittal fracture of the mandibular condyle in children after closed treatment

The aim of this study was to evaluate the outcomes of temporomandibular joint (TMJ) anterior disc displacement and condylar remodelling for sagittal fracture of the mandibular condyle (SFMC) in children. Disc displacement was observed in 20 patients with 24 SFMCs (age 4–12 years) via magnetic resonance imaging. After 6 months of closed treatment (T1), the joints were categorized based on the displaced disc status as complete reduction (DCR) or incomplete reduction (DICR). Moreover, condylar remodelling was compared between the groups using cone beam computed tomography images of the TMJ obtained at T1 and at the 1-year follow-up (T2; 15 patients with 18 displaced SFMCs). At T1, 17 of 24 joints with SFMC were assigned to the DCR group and six to the DICR group; one unilateral SFMC case developed ankylosis. Condylar depth and height differed significantly between the groups at T1, but not at T2. Intra-group comparison exhibited significant changes in the condylar depth and height over time in the DICR group. Thus, most of the anteriorly displaced discs (17/24, 70.8%) achieved reduction following closed treatment. Although sustained anterior disc displacement was associated with an increased depth and reduced height of the condyle, no clinical impairment was noted unless ankylosis developed.     

The presence of bacteria in the synovial fluid of the temporomandibular joint and clinical significance: preliminary study.

PURPOSE: The objective of this study was to find any relation between the presence of specific bacterial species in the synovial fluid of the temporomandibular joint (TMJ) and clinical parameters. PATIENTS AND METHODS: We studied 43 patients (male-to-female ratio, 1:1.69; average age, 34.37 +/- 14.55 years). Thirty-three patients had a displaced disc in the TMJ (DD group), and 10 patients did not have a displaced disc of the TMJ or any symptom related to TMJ disorders (NDD group). Clinical examinations were made to determine maximum mouth opening, joint sounds, previous trauma history, systemic disease, and TMJ pain. Six bacterial species that were reported in other studies were chosen to evaluate the presence of bacteria in the TMJ for this study. RESULTS: Mycoplasma genitalium was most frequently detected in synovial fluid (86.0%). Staphylococcus aureus, Mycoplasma fermentans/orale, Actinobacillus actinomycetemcomitans, and Streptococcus mitis were detected in 51.2%, 37.2%, 25.6%, and 7.0% of samples, respectively. beta-Hemolytic Streptococcus was not detected. The prevalence of S aureus was significantly higher in the DD group than in the NDD group (P <.05). The patients who had M. fermentans/orale were 5.40 times more likely to be younger than 30 years than were those without M. fermentans/orale (P <.05). Those with M. genitalium were 5.81 times more likely to be female than were those without M. genitalium (P <.05). CONCLUSION: The presence of S. aureus in TMJ synovial fluid was related to TMJ disorder symptoms and clinical parameters seemed to be influenced by bacterial presence in TMJ synovial fluid.     

The prevalence of TMJ osteoarthritis in asymptomatic patients with dentofacial deformities: a cone-beam CT study

Osteoarthritis of the temporomandibular joint (TMJ) can be described as non-inflammatory arthritic condition that results in degenerative changes of the joint structures. The aim of this study was to evaluate the skeletal morphology of the TMJ in patients with osteoarthritis with severe skeletal malocclusions (Class II and Class III) and patients with Class I occlusion as controls. Cone beam computed tomography images of 45 Class I, 28 Class II and 44 Class III joints of Caucasian patients were assessed for the presence of any degenerative changes in the condyle and fossa/eminence complex as described in the research diagnostic criteria for temporomandibular disorders (RDC/TMD). In all groups, the most commonly observed features were articular surface flattening and subcortical sclerosis. A combination of features that corresponds to a diagnosis of osteoarthritis was observed in 3% Class I, 43% Class II and 20% Class III patient joints. In conclusion, degenerative TMJ changes were more common in patients with skeletal jaw discrepancies, but wide inter-individual variations can be observed even in patients with clinically similar malocclusions.