Condylar movements of temporomandibular disorder patients with intermittent lock: a pilot study

The purpose of this study was to clarify which direction of the condylar path is advantageous for releasing TMJ intermittent lock. The subjects were ten patients with temporomandibular disorders (TMD) and intermittent lock caused by anterior displacement of disks without obvious medial or lateral displacement. The patients could not open their mouths fully in habitual opening but could open fully in an intentional winding opening with reduction of the anteriorly displaced disks (winding opening). The two kinds of movement at the kinematic condylar point were measured in each subject and compared. The length of the condylar path in winding opening was significantly larger than that in habitual opening. The affected side condyle of winding opening traced medio-inferior paths in the early part of the condylar translation in comparison with habitual opening. From the viewpoint of the condylar path, the medio-inferior direction of condylar translation is thought to be advantageous for releasing intermittent lock.     

Case report of recurrent temporomandibular joint open lock associated with abrupt reduction of displaced articular disk

PatientThis report describes the case of a 51-year-old male patient who initially presented at age 23 with a habitual intermittent open lock (at >35 mm) in the left temporomandibular joint (TMJ). The patient was able to manage this affliction through rapid-repetition jaw opening and closing. Tomography of the joint showed no irregular morphology, but intraoral examination revealed an occlusal interference at the mandibular left third molar during leftwards excursion. For this patient, alteration of lateral guidance using a palatal plate attached to the maxillary left canine precluded this intermittent open lock, but at 22 years of age, the open lock recurred and could not be relieved by the patient, who was unable to assume an occlusal position. Because conservative treatment was ineffective, a pumping manipulation technique was applied to reduce the open lock, after which the patient has maintained good jaw function. MRI taken before and after repositioning indicated that abrupt reduction of a displaced articular disk was the cause of the open lock, and that this articular disk was restored to its proper position during the manipulation.DiscussionMost TMJ open locks occur as anterior dislocation, where the mandibular head becomes trapped anterior to the articular eminences, causing excessive opening and difficulty closing. Our clinical findings from this patient indicate that open lock can occur through abrupt reduction of a displaced articular disk, particularly in patients with chronic internal derangement of the TMJ.ConclusionTMJ open lock can occur following abrupt reduction of a displaced articular disk.     

A study on the rotational torque movement of mandible in patients with TMJ closed lock

The mandibular rotational angle and distance were measured during various movements of temporomandibular joint (TMJ) closed lock patients (17 women, 23.9 +/- 6.6 years). The measurements were compared with those of the healthy controls (18 women, 24.0 +/- 1.4 years) using the BioPAK system (BioResearch Inc. Milwaukee, USA), which can analyze mandibular rotational torque movements. During maximum mouth opening movement, the parameters of the patient group were significantly larger than those of the control group in horizontal plane (p < 0.05) but vice versa in frontal plane (p < 0.001). During protrusive movement, the parameters of patients were significantly larger than those of control group in frontal and horizontal plane (p < 0.01, p < 0.05). During lateral excursive movement to the affected side of patients, the parameters were significantly larger than those to the unaffected side in frontal plane (p < 0.05).     

骨性偏颌患者颞下颌关节的生物力学分析

目的:研究骨性偏颌患者牙尖交错位紧咬牙时颞下颌关节应力分布特征。方法:通过CT和MRI获得影像资料,使用Mimics、CADTIA和Ansysworkbench软件,建立包括颞骨、下颌骨和关节盘的有限元模型,计算咬合时颞下颌关节的应力分布。结果:关节盘和关节窝的主要受力在偏斜对侧分布偏内,偏斜侧分布偏外;偏斜对侧应力是一种集中的方式,偏斜侧是一种分散的方式。结论:偏颌患者偏斜侧关节盘可能倾向于向外侧移位,偏斜对侧关节盘可能倾向于向内侧移位。     

Novel approach to the study of jaw kinematics in an alloplastic TMJ reconstruction

Total alloplastic temporomandibular joint (TMJ) reconstruction is a reliable treatment modality in patients with severely diseased TMJ with good clinical behaviour. TMJ mandibular function after alloplastic reconstruction has scarcely been analysed as a biomechanical parameter and investigation has generally been limited to interincisal measurements without deeper insight into joint kinematics. Dynamic stereometry to assess condylar movements relative to the fossa was performed at the 5 year follow-up of a patient who underwent condylar resection of the right TMJ followed by total alloplastic joint reconstruction to treat pigmented villonodular synovitis. The patient could achieve wide mouth opening, but overall mandibular kinematics showed a strong deviation towards the prosthetic side due to the lack of mandibular translation caused by the absence of the lateral pterygoid attachment. Possible overloading of the joint contralateral to the TMJ prosthesis might be prevented by optimizing replacement joint design.     

Clinical study on the relationship between chewing movements and temporomandibular joint abnormalities

Chewing movements are accomplished by the harmonious function of the stomatognathic system. Therefore, TMJs play important roles in chewing movements. Recently, significant findings on TMJ abnormalities have been obtained from many studies. However, the relationship between chewing movements and TMJ abnormalities remains unclear. The purpose of this study was to examine how TMJ abnormalities were reflected in chewing movements. Incisor point movements during chewing (chewing pattern) were investigated in 150 abnormal and 25 normal subjects using Sirognathograph Analysing System. Abnormal subjects were composed of 45 patients with anterior disk displacement with reduction (reciprocal click), 20 patients with anterior disk displacement without reduction (closed lock), 50 patients with osteoarthrosis and 35 patients with MPD syndrome. Analysis of condylar movements during chewing were also performed in 9 normal and 20 abnormal subjects. The results were as follow; 1. Subjects with TMJ abnormalities tended to show abnormal chewing patterns when chewing at their non-abnormal sides. 2. TMJ abnormality of each different type tended to show its respective characteristic chewing pattern. 1) Subjects with osteoarthrosis and reciprocal click without condylar posterior dislocation tended to show deviation of the turning point to the non-chewing side, with a convex opening path in the frontal plane and a lack of anteroposterior width in the sagittal plane. This finding was associated with the limitation in movement of the abnormal-side condyle. 2) Subjects with reciprocal click with condylar posterior dislocation tended to show a concave opening path and reversed or cross-over patterns in the frontal and horizontal planes, respectively. This finding was associated with the movement of the abnormal-side condyle in the medio-anterior direction during the initial phase of opening. 3) Subjects with closed lock without condylar posterior dislocation tended to show deviation of the turning point to the non-chewing side, with a concave opening path in the frontal plane and a lack of anteroposterior width in the sagittal plane. This finding was associated with the severe limitation in movement of the abnormal-side condyle. 4) Subjects with closed lock with condylar posterior dislocation characteristically tended to show reversed or cross-over patterns in the horizontal plane. This finding was associated with the movement of the abnormal-side condyle in the medio-anterior direction during the initial phase of opening. However, this movement was smaller than that of the reciprocal click. 3. Subjects with MPD syndrome showed chewing patterns similar to those of normal subjects. From the results, close relationships were found between chewing movements and TMJ abnormalities.     

Arthroscopic cauterization of retrodiscal tissue as a successful minimal invasive therapy in habitual temporomandibular joint luxation

Habitual temporomandibular joint (TMJ) luxation is a serious condition for the patient, and is often managed by extensive open joint surgery. Arthroscopic eminoplasty is an alternative, but this technique could also cause concomitant damage to the articular surface. The aim of this study was to evaluate the therapeutic effects and side effects of arthroscopic electrocautery of retrodiscal tissues in habitual TMJ luxation. All patients with habitual TMJ luxations who needed surgical management from 1 January 2000 to 31 December 2009 in the authors’ institution in The Netherlands, were included in this study. All patients were primarily treated with arthroscopic electrocautery. Pre- and postoperative evaluation parameters were: TMJ luxations, maximum mouth opening, translatory capacity, pain and joint noises. Sixteen patients with habitual luxation were treated with arthroscopic electrocautery. Patient reluxation occurred in one. None of the patients had joint pain or mobility restrictions. The overall success rate was 95%. After 86 months there was a high success rate for this therapy. No other morbidity was seen, in contrast with open joint surgery or using sclerosing agents. The authors conclude that arthroscopic eletrocautery of retrodiscal tissues is a highly successful minimal invasive therapy in habitual TMJ luxation without side effects.     

Efficacy of temporomandibular joint arthrocentesis with and without injection of sodium hyaluronate in treatment of internal derangements.

PURPOSE: This study was designed to investigate the efficacy of arthrocentesis with and without injection of sodium hyaluronate (SH) into the upper joint space in the treatment of temporomandibular joint (TMJ) internal derangements. PATIENTS AND METHODS: Forty-one TMJs in 5 males and 26 females aged 14 to 53 years comprised the study material. The patients' complaints were limited mouth opening, TMJ pain and tenderness, and joint noises during function. Patients were randomly divided into 2 groups in which only arthrocentesis was performed in 1 group and arthrocentesis plus intra-articular injection of sodium hyaluronate was performed in the other group. Both groups contained patients with disc displacement with reduction and with closed lock. Clinical evaluation of the patients was done before the procedure, immediately after the procedure, on postoperative day 1, and at 1, 2, 3, 4, 5, 6, 9, 12, 18, and 24 months postoperatively. Intensity of TMJ pain, jaw function, and clicking sounds in the TMJ were assessed using visual analog scales. Maximal mouth opening and lateral jaw movements also were recorded at each follow-up visit. RESULTS: Both techniques increased maximal mouth opening, lateral movements, and function, while reducing TMJ pain and noise. CONCLUSIONS: Although patients benefitted from both techniques, arthrocentesis with injection of SH seemed to be superior to arthrocentesis alone.     

下颌偏斜患者下颌侧方运动时髁突的运动轨迹特征

目的 通过记录下颌偏斜患者的髁突运动轨迹，研究此类患者髁突运动的规律。方法 下颌偏斜患者31例（男性9例，女性22例），年龄12～26岁，平均18岁。使用CADIAX　Ⅲ型髁突运动轨迹轴图描计仪，记录并通过配对t检验和秩和检验分析患者下颌侧方运动时髁突的运动轨迹，并将其与患者下颌偏斜量进行多元线性回归分析。结果下颌偏斜患者下颌侧方运动时髁突的运动轨迹不对称，偏斜侧的运动位移大于非偏斜侧，差异有统计学意义（P＜0．01）；偏斜侧髁突的水平倾斜度小于非偏斜侧，差异有统计意义（P＜0．01）。随着偏斜量的增加，偏斜侧与非偏斜侧髁突的位移差距也相应增加，非偏斜侧髁突的位移相应减小，差异有统计学意义（P＜0．05）。结论下颌偏斜患者不仅颅面形态不对称，下颌侧方运动时髁突运动轨迹在长度、角度等方面也不对称，其与偏斜量有一定的相关性。     

Centers of rotation during jaw movements

Anatomists consider the articulation of movable joints to be complex, involving movable instantaneous centers of rotation (ICR). However, prosthodontists often treat the temporomandibular joint (TMJ) as a model of a simple hinge. The aim of this study was to examine the case for a movable ICR during habitual opening and closing jaw movements. Young, dentate subjects were examined with a kinesiograph. Jaw movements were performed and recorded. The center of rotation of each movement pattern was identified, and its location related to the position of the TMJ. The results showed that opening and closing jaw movements were predominantly non-coincident, with a movable ICR located at a variable distance and direction from the TMJ. There was no evidence to suggest that the TMJ functioned as a simple hinge during jaw movements.     

Bone SPECT imaging of patients with internal derangement of temporomandibular joint before and after splint therapy

OBJECTIVE: Temporomandibular joint (TMJ) patients with disc displacement without reduction have a misaligned disc-condyle structural relation. As the condition becomes chronic, painful osteoarthritic changes may occur. For these patients, splint therapy may help to position the condyle to a more structurally compatible and functional position and to decrease the loading force of articular surfaces. The aim of this study was (1). to evaluate osseous reactions and pain relief in patients with disc displacement without reduction after splint therapy and (2). to use single photon emission tomography (SPECT) bone imaging to compare the results with the opposite joint of the patient. STUDY DESIGN: Twelve patients, who presented with pain involving the TMJ and limited mouth opening and were confirmed by soft tissue imaging as having disc displacement without reduction, were included in the study. Each patient underwent bone SPECT imaging, after which semiquantitative evaluation of transaxial images was conducted. The ratios of affected TMJ to nonaffected TMJ, affected TMJ to occipital bone, and nonaffected TMJ to occipital bone were calculated. After 6 months of splint therapy, bone SPECT examinations were repeated. RESULTS: Before splint therapy, the ratios of affected TMJ to nonaffected TMJ and of affected TMJ to occipital bone were found to be significantly higher than the ratios after splint therapy (P < 0.005). CONCLUSION: Six-month splint therapy has a positive effect on the osseous reaction and pain related to internal derangements of TMJs.     

Transport distraction osteogenesis as a method of reconstruction of the temporomandibular joint following gap arthroplasty for post-traumatic ankylosis in children: a clinical and radiological prospective assessment of outcome

This clinical and radiographic study investigated the use of transport distraction osteogenesis in unilateral temporomandibular joint (TMJ) ankylosis patients. Six patients aged between 4 and 8 years were selected for the study; the mean preoperative maximal inter-incisal opening (MIO) was 3.5 mm without lateral and protrusive mandibular movements. The ankylotic mass along with the posterior border of the ascending ramus was exposed via ‘lazy-S’ incision. A gap arthroplasty was performed, followed by a ‘reverse L’ osteotomy on the posterior border of the ramus. In-house manufactured extraoral distraction devices were used for this prospective study. Follow-up clinical and radiographic evaluation was carried out for 13–27 months after completion of the activation period. After a mean follow-up of 19 months, the mean MIO was 29.1 mm and the lateral and protrusive movements changed from none to slight. Cone beam computed tomography images of all patients showed remodelled neocondyle created by transport distraction osteogenesis with no statistically significant differences observed for average cancellous bone density, trabecular number, and trabecular spacing between the neocondyle of the operated side (test) and the condyle of the non-operated side (control). Neocondyle formation by transport distraction osteogenesis using the in-house distraction device is a promising treatment option for TMJ reconstruction in ankylosis patients.     

Long-term results of functional open surgery for the treatment of internal derangement of the temporomandibular joint

We studied 20 consecutive patients with internal derangements of the temporomandibular joint (TMJ), a median of 51 months after open operation on the joint and a rehabilitation programme. The design was a retrospective clinical study. The maximal opening and lateral active movements and the presence of clicking and joint pain were recorded preoperatively, after complete rehabilitation, and at the time of follow-up. Patients completed visual analogue scales of pain before operation and at the time of follow-up. Operation and postoperative rehabilitation reduced the variability of the opening and lateral movements, significantly increased maximal opening, and reduced clicking and pain.     

Clinical, radiographic, and electromyographic study of patients with internal derangement of the temporomandibular joint

Fifteen patients with internal derangement of the temporomandibular joint (TMJ) were examined clinically, radiographically, and electromyographically. Electromyographic recordings were also obtained from 11 subjects without signs or symptoms associated with their TMJs or masticatory musculature. All the patients with internal derangement demonstrated interferences on the ipsilateral side. This was interpreted as the result of disc displacement producing a reduced joint space and, consequently, a decreased vertical dimension on the symptomatic side. Slow opening and closing mandibular movements without clenching could be performed by healthy persons without noticeable EMG activity in the temporalis and masseter muscles. In association with disc displacement, electromyographic activity of the temporalis and masseter muscles occurred when the condyle slid over the posterior band of the disc and could be interpreted as an arthrokinetic reflex caused by distraction. Continuous muscle activity could be provoked by TMJ disc displacement and ceased when the disc position was normalized on mouth opening, only to occur again every time the disc became displaced on mouth closure. Anterior disc displacement without reduction (closed lock) could cause spastic activity in the temporalis muscle on the affected side. Spastic activity of the masseter and temporalis muscles occurring on the same side as a joint with anterior disc displacement hinders or inhibits the condylar movement necessary to achieve reduction.     

偏突颌患者颞下颌关节盘冠状向位置的MRI评估

目的研究偏突颌畸形患者双侧颞下颌关节盘-髁突位置在冠状位磁共振图像(magnetic resonance imaging,MRI)上的差异,并分析其关节盘移位程度与偏斜严重程度的相关性。方法对54例骨性Ⅲ类错患者进行标准化临床影像学检查得到闭口斜冠状位MRI,通过计算机软件测量分析其冠状位关节盘内外侧移位情况,应用wilcoxon秩和检验分析各组间颞下颌关节盘-髁位置在冠状位磁共振图像上的差异。结果40例偏突颌畸形患者中,偏斜侧7侧(17.5%)关节盘外侧移位,16侧(40.0%)内侧移位;而40侧偏斜对侧关节盘中,27侧(67.5%)关节盘内侧移位,仅2侧(5.0%)关节盘向外侧移位。14例(28侧)无偏斜骨性Ⅲ类患者中,18侧(64.3%)存在关节盘内侧移位,未发现外侧移位的关节盘。本研究证实了偏斜侧关节盘内外侧位置与偏斜对侧及无偏斜组存在显著性差异(P<0.05),中等到重度偏突颌患者偏斜侧关节盘位置与轻度及无偏斜者之间的差异具有统计学意义(P<0.05)。结论在冠状位磁共振图像中显示,中等到重度偏突颌患者偏斜侧关节盘倾向于向外侧移位,偏斜对侧关节盘倾向于向内侧移位。     

Movement of temporomandibular joint tissues during mastication and passive manipulation in miniature pigs

Movement is an important aspect of the biomechanics of the temporomandibular joint (TMJ). To track the relative movements of TMJ components, radio-opaque markers were implanted in the left squamosal bone, mandible and retrodiscal tissue of miniature pigs. Medial-lateral (ML) and dorsal-ventral (DV) fluoroscopic records were made 8-10 weeks later during chewing and passive manipulation. Marker movements were digitized from the videotapes. During passive manipulation, the deformation of the lateral capsule was also measured with a differential variable-reluctance transducer. The results provide new details about porcine chewing pattern, which is distinguished by a regularly alternating chewing side. During masticatory opening, the mandible had a centre of rotation (CR) well inferior to the condyle and close to the angle. In contrast, the passive opening movement showed a higher CR location close to the condylar neck, indicating a different motion from masticatory opening. The retrodiscal tissue followed the movements of the mandibular condyle during both mastication and passive manipulation. The lateral capsule elongated during ipsilateral shifts and retrusion, implying a possible role in limiting such movements. These movement characteristics provide a useful reference for studies on the TMJ using pigs.     

Masticatory muscles. Part VI. Masticatory muscles and movement of the lower jaw

The movement paths of the kinematic center of the temporomandibular joint were recorded by means of a jaw movement recording system (OKAS-3D) under 3 conditions: 1. free open and close movements; 2. free opening and loaded closing movements (subjects closed against a small, manually applied, downward directed force on the chin); and 3. during chewing of chewing gum. During free jaw movements, the opening path of the kinematic center lies above the closing path. During loaded closing movements, the opening and closing paths coincide. This indicates that during opening and loaded closing, the condyle-disc complex is slightly pressed against the articular eminence. However, during free closing, there is more space between the articulating surfaces. During gum chewing, the opening and closing paths of the condyle coincide on the balancing side, on the working side they don't. Thus, the joint on the balancing side is loaded and the joint on the working side is not.     

Sound analysis of temporomandibular joint internal derangements with phonographic recordings

STATEMENT OF PROBLEM: Temporomandibular joint (TMJ) sound recordings could be analyzed to assess the state of TMJ internal derangements. PURPOSE: The aim of the study was to assess the value of sound analysis in the diagnosis of the type of the TMJ internal derangements. MATERIAL AND METHODS: After clinical and radiologic examinations, phonographic sound recordings on mandibular excursions were obtained in 52 patients with TMJ internal derangements and 12 control individuals. Sound correlations were made on the basis of opening-closing, protrusive-retrusive, and lateral excursions of the mandible. RESULTS: Clicking was a consistent finding of anterior disc displacement with reduction, whereas crepitation was found in varying degrees in anterior disc displacement and osteodegenerative arthritis. Silent TMJs were the feature of normal TMJs, except for the situations of acute lock. Although in 29 TMJs opening click was followed by a closing click (reciprocal clicking), 46 TMJs with opening click also had clicking on protrusion. On the other hand, 19 TMJs with opening click also had clicking on ipsilateral motion, and 40 TMJs with opening click had clicking on contralateral motion of the mandible. The sound patterns were found to be similar in opening-protrusive clicks and opening-contralateral clicks. The lack of protrusive clicking in the presence of opening click was considered an indication of late disc reduction on opening. Crepitation was observed in advanced cases of TMJ internal derangements. CONCLUSION: Within the limitations of this study, the results suggest that TMJ sound analysis on mandibular excursions was indicative for diagnosis and establishment of severity of TMJ internal derangements. Clicking and crepitation may be looked on as signs of abnormal joint disorder, clicking indicating anterior disc displacement with reduction, and crepitation, indicating progression from anterior disc displacement without reduction to osteodegenerative arthritis.     

Dynamic stereometry of the temporomandibular joint

Studies on jaw kinematics have provided a good understanding of the motion of the mandible in space, but are of little biomechanical relevance because they could not relate the movements to anatomic structures. This is possible by the combination of three-dimensional reconstructions of the temporomandibular joint (TMJ) anatomy with jaw motion recordings. This technique allows us to analyze the variation of the relationship between the articular surfaces, providing indirect insight into disk deformation during function and parafunction as well as TMJ loading. As far as the variation of the condyle-fossa distance is concerned, data indicated that during chewing the distance was smaller 1) on closing than on opening; 2) on the balancing than on the working side; and 3) during chewing of hard than soft food. Moreover, during a forceful static biting, the condyle-fossa distance decreased more on the contralateral, i.e. on the balancing side than on the working side. The decrease was related to the degree of clenching force. These results support the content that both condyles are loaded during chewing and the balancing side joint more than the working one. Biomechanically, the development of osteoarthrosis is more likely related to the magnitude and frequency of stresses applied on the cartilage. Joint movements produce tractional forces that may cause shear stresses contributing to cartilage wear and fatigue. Tractional forces are the result of frictional forces caused by the cartilage surface rubbing and of plowing forces caused by the translation of a stress-field through the cartilage matrix, as the intra-articular space changes during motion. Translation of the stress-field in mediolateral direction seems to be particularly important for the integrity of the TMJ disk because of its anisotropic properties. Dynamic stereometry showed that stress-fields translate in mediolateral direction during opening/closing, protrusion and laterotrusion, and that their translatory velocity varies intraindividually and with the rate of the condylar movement. Furthermore, the results seem to indicate that the lateral area of the TMJ disk is more often exposed to shear stresses caused by stress-field translation than the medial one. In conclusion, dynamic stereometry provides a good visualization of the movement of the condyles in the respective fossae. This helps improving our understanding for the complexity of condylar movements. The technique may also contribute to ameliorate our knowledge of TMJ biomechanics and therefore of the etiology of degenerative joint diseases and possibly also of internal derangement.     

Body posture during sleep and disc displacement in the temporomandibular joint: a pilot study

Many possible factors associated with internal derangement of the temporomandibular joint (TMJ) have been discussed, but the causal factors remain unproven. The present study aimed to investigate habitual body posture during sleep (HBP) of patients with anterior disc displacement (ADD) in the TMJ. The sample comprised 87 patients (12 males, 75 females) aged 13-68 years (mean 25 years) and diagnosed by magnetic resonance imaging as having unilateral or bilateral ADD in the TMJ. The HBPs were classified into five categories: supine, prone, right lateral, left lateral, and no-dominant positions. Of the 50 patients with the unilateral ADD, 33 (66%) had the ipsilateral HBP to the affected joint while none (0%) had the contralateral HBP. This contrast showed that the HBP was a possible contributing factor to the ADD. It was suggested that HBP allows the ipsilateral condyle to displace posteriorly and this posterior position causes relative ADD.