Effect of occlusal splints for the management of patients with myofascial pain: a randomized, controlled, double-blind study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Occlusal splints have been the preferred modalities in the management of myofascial temporomandibular disorders (TMDs), but now controversy exists in reporting whether they are successful for TMDs treatments. The aim of this study was to give objective evidence to the assessment of treatment effect of occlusal splints for myofascial TMDs patients by clinical assessments and surface electromyography (sEMG) measurements of masseter muscles (MM).</p><p><b>METHODS</b>Thirty-six patients (12 males and 24 females) aged 16 - 57 (38 ± 11) years participated in the study. All participants diagnosed with myofascial TMD were randomized into two groups (18 of each). Patients in the first group (A) were treated with occlusal splints for 1 month, while patients in the second group (B) were treated with placebo (non-occluding palatal) splints. Clinical assessments were performed at the beginning of the study and 1 month after treatment. sEMG measurements for MM were performed at mandibular postural position (MPP) and maximum intercuspal contacted position (ICP) 1 month after the treatment. The root mean square (RMS) and the median frequency (MF) as linear indices of sEMG data were used to demonstrate muscle activity and muscle fatigue. Data were analyzed by ANOVA and post hoc SNK test. The differences were considered significant at P < 0.05.</p><p><b>RESULTS</b>It was found that 89% of group A either completely recovered (39%) or clinically improved (50%), while only 22% of group B had a spontaneous improvement. sEMG analysis showed that at MPP, the mean of RMS value of MM in group A was lower than that of group B, which shows statistical differences (P < 0.01). At ICP, the RMS value of MM in group A was higher than that of group B, which shows statistical differences (P < 0.01). At MPP, MF value of MM in group A was higher than that of group B (P < 0.05). At ICP, MF value of MM was lower than that of group B (P < 0.01).</p><p><b>CONCLUSIONS</b>Occlusal splint could eliminate or improve the signs and symptoms of TMD patients with myofascial pain. sEMG analysis indicates that the wearing of occlusal splints may reduce the degree of fatigue of the masticatory muscles. The splint therapy outcome has a correlation with the electromyographic changes in the masticatory muscles.</p>

Differentiation and functional expression of highly purified osteoclast-like cells in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To establish a culture method for a large amount of highly purified osteoclast-like cells in vitro. To investigate the gene expression of some osteoclast marker enzymes. To lay the foundation for the further study of the signal path on the differentiation and formation of osteoclast-like cells.</p><p><b>METHODS</b>The bone marrow mononuclear cells of rat were treated with 30 ng/mL macrophagecolony-stimulating factor (M-CSF) and 50 ng/mL receptor activator of NF-kappaB ligand (RANKL) and cultured for 6 days. After culturing, cells were evaluated by morphology observation, tartrate-resistant acid phosphatase (TRAP) staining, Giemsa staining, pit staining, and the gene expression of some osteoclast marker enzymes.</p><p><b>RESULTS</b>The TRAP-positive mononuclear cells were more frequently observed than the multinucleated cells and pit staining could be seen on the dentine slice. The transcription expression of TRAP, matrix metalloproteinase-9 (MMP-9), membrane-type1-matrix metalloproteinase (MT1-MMP) and cathepsin K were detected by RT-PCR.</p><p><b>CONCLUSION</b>The cooperation of M-CSF and RANKL could induce a large amount of highly purified osteoclast-like cells formation in rat bone marrow culture. The typical characteristics of osteoclast-like cells were demonstrated and the enriched osteoclast-like cells expressed TRAP, MMP-9, MT1-MMP and cathepsin K.</p>