The Relationship Between Temporomandibular Joint Mobility and Peripheral Joint Mobility Reconsidered

The purpose of this paper was to study the relationship between temporomandibular joint (TMJ) mobility and mobility of joints and to study the general character of joint mobility in 83 subjects, 55 females and 28 males (mean age 26.7, range 13–46 years). The subjects were recruited from the Department of Oral and Maxillofacial Surgery of the University Hospital of Groningen. All participants had a good general health and did not present anamnestically, clinically or radiographically TMJ disorders. Of these subjects, angular displacement of the mandible relative to the cranium during maximal mouth opening (AMO) was measured. Furthermore, the maximal range of motion of passive digit five hyperextension, passive thumb apposition to the wrist, active elbow and knee hyperextension, active ankle dorsal flexion and trunk flexion were measured. All measurements were performed bilaterally, except trunk flexion. Calculation of product moment correlations (Pearson) revealed a weak relationship between AMO and mobility of right digit five and elbows for the total group and between AMO and mobility of both digits five and elbows for women. The correlations were never stronger than 0.4. Multiple regression revealed that only 25.9% of the total variance of AMO could be explained by mobility of peripheral joints, age and sex. Calculation of product moment correlations between mobility of peripheral joints, trunk flexion and age revealed weak correlations between the different joints, with the exception of paired joints. Principal component analysis revealed a weak general character of joint mobility. It is concluded that mobility or hypermobility of the TMJ cannot be predicted on the basis of mobility or hypermobility of other joints and that mobility of any peripheral joint cannot be predicted on the basis of the degree of mobility of other joints.     

髁突位置与颞下颌关节盘移位关系的研究

在颞下颌关节内紊乱（TMJID）的患者中髁突位置和关节盘移位之间的关系一直是研究者所关注的问题,许多学者从不同的角度进行了探索,但对TMJID患者髁突在关节窝中的位置及其临床意义存在争议。本文就TMJID概况、髁突位置与关节盘移位的关系及其在TMJID诊断中的意义作一综述。     

Anatomy of the Temporomandibular Joint and Related Structures in the Frontal Plane

Conclusions about the anatomy and physiology of the temporomandibular joint have too often been based on sagittal representations. The aim of the article is to describe frontal serial cuts of an acrylic embedded articulation of a subject with teeth in intercuspal position. The frontal plane is best to visualise the difference between lateral and medial aspects of structures such as the disk-condyle-complex, the articular capsule, and related muscles.     

Mandibular Instantaneous Centers of Rotation in Patients With and Without Temporomandibular Dysfunction

PATIENTS AND METHODS: The free opening movement of the mandible was examined in 30 patients with and without dysfunctions, using the CADIAX electronic axiography system. All patients in the diseased group showed dysfunctions in the left temporomandibular joint. Half of the 20 asymptomatic patients were skeletal Class II, the other half skeletal Class III. Based on the data collected for the left temporomandibular joint, the movement of the mandible during the mouth-opening movement in the sagittal and vertical planes was described as the pathway over time of the various instantaneous centers of rotation (ICR), using physico-biomechanical factors. RESULTS AND CONCLUSION: It emerged that the ICR path in the patients with dysfunctions was irregular with erratic changes of direction. A harmonious ICR path beginning near the condyle was typical of the healthy group; as the mouth opened, the path moved toward downward backward and finally shifted toward forward and forward upward. Therefore, such an ICR path pattern can be used as an indicator in detecting dysfunctions.     

Correlation of Occlusal Factors and Condyle Position Asymmetry with Signs and Symptoms of Temporomandibular Disorders in Young Adults

The role of the occlusion in the etiology and prevalence of temporomandibular disorders (TMD) has not been conclusively demonstrated. Occlusal factors and condyle position asymmetry as deduced from computed tomography (CT) axial scans were correlated with signs and symptoms of TMD in 49 young adults (mean age 24 years, range 15–33 years) with complete or almost complete dentition. A statistically significant correlation was noted between these signs and symptoms and occlusal variables describing asymmetry (the amount and lateral deviation of the slide from the retruded contact position (RCP) to the intercuspal position (IP), deviation of protrusion and asymmetry in bilateral cuspid occlusion). It seems that occlusal discrepancy can be a predisposing factor to TMD, especially when it is asymmetrically expressed.     

The Position of the Occlusal Plane in Natural and Artificial Dentitions as Related to Other Craniofacial Planes

Purpose: This study aimed at determining the most reliable ala‐tragus line as a guide for the orientation of the occlusal plane in complete denture patients by use of cephalometric landmarks on dentate volunteers. Materials and Methods: Analysis was made for prosthodontically related craniofacial reference lines and angles of lateral cephalometric radiographs taken for 47 dentate adults. Variables were determined and data were analyzed using SPSS (SPSS, Inc., Chicago, IL). Results: Occlusal plane angle formed between the occlusal plane and Camper's plane had the lowest mean value in the angle formed with Camper's I, which represents the measure taken from the superior border of the tragus of the ear with a score of 2.1°. The highest was measured in the angle formed with Camper's III with a score of 6.1°, while the angle formed with Camper's II was 3.2°. The differences between the three planes in relation to the occlusal plane was significant (p < 0.001). Conclusion: The superior border of the tragus with the inferior border of the ala of the nose was most accurate in orienting the occlusal plane.     

腭裂引起反的前牵引与下颌髁突位置关系的初步研究

目的　评价应用口外弓加面具对唇腭裂继发骨性反牙合畸形进行早期阻断性治疗后 ,下颌骨髁突位置的变化。方法　对 8例患者治疗前和治疗 6个月的薛氏位片进行分析 ,比较颞下颌关节 (TMJ)前、上、后间隙的宽度。结果　治疗前后双侧TMJ的 3个间隙均无明显改变 (P >0 .0 5 )。结论　应用口外弓加面具作上颌骨前牵引后 ,未发现髁突位置的明显改变。     

Nonsurgical Treatment of Anterior Disk Displacement Without Reduction of the Temporomandibular Joint: A Case Report on the Relationship between Condylar Rotation and Translation

Farrar reported that in chronic anterior disk displacement without reduction (ADD w/o R) of the temporomandibular joint (TMJ), the range of mandibular movement gradually increases and the condylar movement normal-disk is still displaced anteriorly. The relationship between condylar rotation and translation was studied in opening/closing jaw movements before and after joint stabilization splint therapy in a patient with ADD w/o R. Movements were recorded by means of an optoelectronic jaw tracking system (Metropoly, Jaws-3D) consisting of three cameras that register the position of six light-emitting diodes (LEDs) mounted on two target frames separately attached to the upper and lower jaw. A computer produced plots of the condylar paths in the sagittal, frontal, and horizontal plane, as well as the opening angle against the anterior condylar translation. Results indicated some variations in the relationship between condylar rotation and translation during jaw opening movement. In the joint with ADD w/o R an increase in anterior condylar translation was found and the relationship between rotation and translation became more linear after joint stabilization therapy. This study supported a hypothesis of Farrar's that condylar movement in chronic ADD w/o R is similar to that expected in asymptomatic TMJs.     

The Relationship Between Retruded Contact Position and Intercuspal Position in Patients with TMJ Osteoarthritis

This study was conducted to investigate the relationship between posterior mandibular excursion movement and temporomandibular joint osteoarthritis (TMJ OA) in 25 orthodontic patients with Angle Class I and Class II, using a six degrees-of-freedom measuring device and helical computed tomography. There were significant differences found in three-dimensional length, antero-posterior, absolute latero-medial and supero-inferior incisal, and condylar intercuspal position (IP)-retruded contact position (RCP) slides between bilateral, unilateral, and no condylar bone change groups. With respect to the types of condylar bone change, there were significant differences found in three-dimensional length, antero-posterior, and absolute latero-medial condylar IP-RCP slides between flattening, erosion and osteophyte groups. These results suggest that large three-dimensional, not only incisal but also condylar, IP-RCP slides might be related to the uni-/bilaterality and kind of TMJ pathosis, which might make such slides useful as clinical indices of TMJ OA.