Magnetic resonance imaging of temporomandibular joint: morphometric study of asymptomatic volunteers.

BACKGROUND: The aims of this study were to determine the best suited magnetic resonance imaging scanning plane, scanning sequence, and imaging modality for the evaluation of the temporomandibular joint (TMJ) and quantitatively assess the relationship of articular disk position to condyle position. METHODS: One hundred four TMJs in 52 symptom-free heads were examined by magnetic resonance imaging. The best scanning plane, scanning sequence, and scanning parameter were determined according to the imaging time and image quality. Bilateral symmetry of the articular disk and mandibular condyle was measured by using the automatic measurement of 3.0-T GE Excite Signa MR scanner. RESULTS: Fast spin-echo sequence, oblique sagittal imaging plane, and proton density imaging were the best suited scanning sequence, scanning planes, and imaging modality, respectively. The thicknesses of the anterior and posterior bands and for the intermediate zone were not statistically different for both sides. The posterior band of the disk was found to originate in an area adjacent to the 12-o'clock position of the condyle (± 5 degrees), whereas the anterior band of the disk originated adjacent to 1-o'clock position (28 ± 6 degrees). The anteroposterior diameter and mediolateral diameter of the condylar processes were not statistically different for both sides. The axial condylar angle between the plane of the greatest mediolateral diameter of the condylar processes and the midsagittal plane were also not statistically different for both sides. CONCLUSIONS: The magnetic resonance images can depict clearly major regional anatomic structures and position in the TMJ, which can be used in the early diagnosis for the TMJ disorder.

[Histopathological study of the effects of intra-articular injection of triamcinolone acetonide on temporomandibular joint osteoarthrosis in goats].

PURPOSE: The aim of this study was to investigate the histopathological changes of human temporomandibular joint osteoarthrosis following intra-articular injection of triamcinolone acetonide, and compare the results to these of control group. METHODS: The upper compartments of both joints of 10 goats were injected with 0.8 ml collagenase I to induce osteoarthrosis. The 10 goats were then equally divided into control group and experimental group. The first and second treatment were carried out 30 and 60 days after injection of collagenase I, respectively. The animals were sacrificed 90 days after the first treatment. The specimens of the animal TMJ were harvested, histologically examined under light microscopy and scanning electron microscopy, and scored in a subjective manner following the criteria which was a modification of the method of Mankin et al and Yoshimi et al. GLM model in SAS software package was adopted to compare the differences between the control group and experimental group. RESULTS: Under light microscopy and scanning electron microscopy, the condyle, meniscus and glenoid fossa of the control group demonstrated distinct osteoarthrosis; the histopathologic changes in the experimental group was more serious than the control group, and the differences of the histologic scores were significant between the two groups (P<0.01). CONCLUSION: Intra-articular injection of triamcinolone acetonide as a lytic agent will worsen for articular cartilage reparation.

[Electromyography study on complete bilateral cleft lip after reparation.].

PURPOSE: This study was undertaken to evaluate the motion effect of complete bilateral cleft lips objectively using electromyography. METHODS: 45 patients of complete bilateral cleft lips after operations several years which included 20 patients repaired using orbicularis oris muscle restoring functional method and 25 patients using straight line suture method were examined with electromyography (EMG) in prolabium, right and left lateral lips respectively. The most potential in every area of each patient at the maximal lip contraction position was measured and the values of two different method groups were subject to statistical analysis. RESULTS: The prolabium and lateral lips of both groups had no electric activity at posture position. At maximal contraction position, the mean potential of prolabium of orbicularis oris muscle restoring method group had no difference with the lateral lips. But the mean potential of prolabium of straight line suture method group was lower than that of the lateral lips significantly,also,it was lower than the potential of prolabium in the muscle functional reparation group. CONCLUSIONS: The reparation method of restoring orbicularis oris muscle to complete bilateral cleft lips was better than the straight line suture method in the motion effect. These findings suggest the superiority and necessity of functional muscle reparation for complete bilateral cleft lips.