The present study proposes a method delineating the extent of the anterior displacement of the temporomandibular articular disc through the angle formed by the deepest point in the glenoid fossa, the center of the mandibular condyle and the junction between the end of the posterior band and the retrodiscal tissue. The method was applied to the normal group and TMD group. The TMD group was further divide into 3 groups Group I(little disc displacement), Group II(anterior disc displacement with reduction) and Group III(anterior disc displacement without reduction). The results were as follows. 1. The normal group showed the location of the articular disc within -10-0degree or with a wider allowance, within -10-10degree from the reference line GC. 2. The TMD group showed the disc located within -21.0-125.8degree,with two peaks at 0-100 and 60-800, suggesting that the group may be composed of more than two different subgroups. 3. The threshold point delineating the normal and TMD states was 0degree, because 82.5% of normal group appeared below 0degree and 94.8% of TMD group appeared above 0degree. 4. Since the angular disc displacement tends to increase from Group I to Group III, the angular displacement increases as the overall severiety of the disease increases, and the chance for a reduction of the disc decreases. 5. The normal group, Group I, Group II, and Group III can be categorized into statistically different groups. The normal group and TMD group can be distinguished in reference to 0degree, while the presence-absence of the anterior disc displacement is judged in reference to 10degree, and the probability of the disc reduction can be estimated in reference to 50degree. The present study assesses the location of the articular disc from the sagittal central section offering a supplementary clinical classification. This system provides an additional information concerning the location of the disc, thereby offering an objective mean to evaluate the progress of the disease. Further studies may be needed on the clinical changes according to location of the disc, as well as the relationship between the morphological changes and the anterior or sideways displacement of the disc.
Classification ; Mandibular Condyle ; Temporomandibular Joint Disc ; Temporomandibular Joint*

No abstract available.
Ear Cartilage* ; Temporomandibular Joint Disc* ; Temporomandibular Joint* ; Transplants*

No abstract available.
Cartilage ; Rabbits ; Temporomandibular Joint Disc ; Temporomandibular Joint ; Transplants

temporomandibular joint (TMJ) is common, but long-standing dislocation is rare. We present two cases of the exophytic condylar hyperplasia that lasted for over 20 years with TMJ dislocation. In both cases, we performed a condyloplasty to restore normal occlusion and facial symmetry, with satisfactory results.]]>
Dislocations ; Facial Asymmetry ; Hyperplasia ; Temporomandibular Joint Disc ; Temporomandibular Joint

OBJECTIVETo assess the diagnostic value of high-resolution ultrasonography for detecting of anterior disc displacement without reduction (ADDWR) of temporomandibular joint (TMJ).

METHODSThirty-five participants with 40 TMJs which were initially diagnosed as ADDWR were included. All the participants got both high-resolution ultrasonography and MRI examination. The results of MRI in diagnosis of ADDWR were considered as gold standard. Sensitivity, specificity, accuracy, positive predict value, negative predict value, positive likelihood ratio and negative likelihood ratio were calculated.

RESULTSIn 40 TMJs, MRI revealed that there were 23 TMJs with ADDWR, and 17 disease-free. The sensitivity, specificity, accuracy, positive predict value, negative predict value, positive likelihood ratio and negative likelihood ratio of high-resolution ultrasonography were 82.6%, 94.1%, 92.5%, 0.95, 0.80, 14.04, 0.19, respectively.

CONCLUSIONThe high-resolution ultrasonography has a relatively high diagnostic value in detecting ADDWR of TMJ.

Humans ; Joint Dislocations ; Magnetic Resonance Imaging ; Sensitivity and Specificity ; Temporomandibular Joint ; Temporomandibular Joint Disc ; Temporomandibular Joint Disorders

PURPOSE: This study was aimed to investigate the relationship between the mandibular asymmetry and the internal derangement of temporomandibular joint. MATERIALS AND METHODS: One hundred and sixty eight patients had been assessed through clinical examinations, panoramic radi-ographs and magnetic resonance imagings (MRIs), were selected. The samples were classified into three subgroups according to the severity of the mandibular asymmetries in the panoramic radiographs and the status of TMJ discs on the MRI were compared among each groups. RESULTS: In an apparent asymmetry group, there was a significant difference in the number of temporomandibular disk displacement without reduction between the long and short side (66.7%, 18/27 joints on the short side) when the ratio of condylar process and coro-noid process was used (P<0.05), but there was no statistically significant difference when the ratio of condyle and ramus was used. CONCLUSION: The probability of the disc displacement without reduction was higher at the side with relatively shorter condylar process on the panoramic radiograph, and also it might be more effective to use ratio of condylar process and coronoid process in the assessment of mandibular asymmetry. Therefore, a careful assessment on the temporomandibular disorders is necessary to diagnose and establish the treatment plans for the patients with a mandibular asymmetry and the panoramic radiograph can be used effectively on that way.
Humans ; Joints ; Magnetic Resonance Imaging* ; Temporomandibular Joint Disc* ; Temporomandibular Joint Disorders ; Temporomandibular Joint*

PURPOSE: To evaluate the osseous changes of TMJ in internal derangement and osteoarthritis patients using MRI. MATERIALS AND METHODS: MR images of 111 TMJs in 64 patients were analyzed to evaluate the osseous changes. 111 TMJs were divided into 6 groups according to the radiologic Stages by Schellhas and Wilkes. On MR images, we evaluate the osseous changes of articular eminence and condylar head. RESULTS: The most frequent Stage in internal derangement of TMJ was Stage I. And 28 joints (25.2%) revealed osteoarthritis with internal derangement. When osseous change of articular eminence and condylar head occur, flattening was the most common osseous change. Sclerosis was observed in all Stages and osteophytosis of condylar head was observed in Stage II (1.8%) and III (0.9%). Out of 28 joints with osteoarthritis, 6 joints (21.4%) showed joint effusion. CONCLUSION: MR image revealed abnormal configuration of disk, but the detection of minimal osseous change was subtle.
Head ; Humans ; Joints ; Magnetic Resonance Imaging* ; Osteoarthritis* ; Sclerosis ; Temporomandibular Joint Disc ; Temporomandibular Joint Disorders ; Temporomandibular Joint*

PURPOSE: To investigate the hypothesis that the morphology of the articular eminence of the temporomandibular joint is a predisposing factor for disc displacement. MATERIALS AND METHODS: MR images of 126 temporomandibular joints in 94 patients were analyzed to assess for morphology of the articular eminence and disc displacement. The displaced disc was further categorized as disc displacement with reduction (DDWR) and disc displacement without reduction (DDWOR). The morphology of the articular eminence was classified into four types; box, sigmoid, flattened, and deformed. The relationship between the four types of shape of the articular eminence and the two types of disc position was assessed. RESULTS: In the DDWR and DDWOR groups, the morphology of articular eminence were a box type in 40.5%, a sigmoid type in 30.2%, a flattened type in 24.6%, and a deformed type in 4.7%. The box type of the articular eminence were 34.3% in the DDWR group and 42.9% in the DDWOR group. The sigmoid type of the articular eminence were 34.3% in the DDWR group and 28.6% in the DDWOR group. The flattened type of the articular eminence were 28.6% in the DDWR group and 23.1% in the DDWOR group. The deformed type of articular eminence were 2.9% in the DDWR group and 5.5% in the DDWOR group. CONCLUSION: Disc displacement is more likely to be found in the temporomandibular joints with a box-shaped articular eminence. It can be considered that shape of the articular eminence is related to the development of disc displacement.
Causality ; Colon, Sigmoid ; Humans ; Magnetic Resonance Imaging ; Temporomandibular Joint Disc ; Temporomandibular Joint Disorders ; Temporomandibular Joint*

OBJECTIVETo investigate the efficacy of S-methylisothiourea (SMT) for treatment of temporomandibular joint osteoarthrosis (TMJOA) of goats.

METHODSNine purebred black goats were randomly devided into three groups: Normal control group, control group and experimental group. The upper compartments of both temporomandibular joint of the goats in control group and experimental group were injected with collagenase only once to induce osteoarthrosis. Normal control group received no treatment. The upper compartments of both TMJ were injected with 0.5 mL of normal saline, and experimental group, the upper compartments of both TMJ were injected with 0.5 mL of SMT. The TMJ of goats was examined with scanning electron microscopy and microscopy after sacrificed.

RESULTSExamined in light microscopy and scanning electron microscopy, normal control group showed normal performance, the control group showed severe osteoarthrotic changes in the temporal surface, disk and condyle, while the experimental group showed improvement of different degree.

CONCLUSIONOn the basis of 3-month following-up study, repeated intra-articular injection of SMT may play a role in inhibiting TMJOA progression.

Animals ; Injections, Intra-Articular ; Isothiuronium ; analogs & derivatives ; Osteoarthritis ; Temporomandibular Joint ; Temporomandibular Joint Disc ; Temporomandibular Joint Disorders

OBJECTIVETo compare the vibration parameters in reducible anterior disc displacement and symptomless youth, and explore the clinical diagnostic value of frequency spectrogram of temporomandibular joint (TMJ) sounds.

METHODS21 youth with anterior disc displacement were included as experimental group, and 26 symptomless youth were included as control group. The joint vibrations during rhythmic maximal open-close jaw movement of all subjects were recorded. The sensitivity and specificity of total integral in diagnosis of reducible anterior disc displacement were calculated.

RESULTSAll TMJ vibration parameters, include total integral, integral < 300 Hz, integral > 300 Hz, > 300/< 300 Hz radio, peak amplitude, peak frequency and median frequency, were significantly higher in experimental group than that in control group (P < 0.05). Along with the increasing of disc displacement degree, the TMJ vibration parameters were increasing, and total integral significantly increased (P < 0.05). The total integral demonstrated a high sensitivity and specificity in diagnosis of anterior disc displacement with reduction (0.86 and 0.85, respectively).

CONCLUSIONThe TMJ vibration parameters are significantly higher in youth with reducible anterior disc displacement than that in symptomless youth. Different pathological stages of disc displacement show different TMJ sounds.

Adolescent ; Female ; Humans ; Male ; Sensitivity and Specificity ; Sound ; Temporomandibular Joint ; Temporomandibular Joint Disc ; Temporomandibular Joint Disorders ; Vibration