Is SEMG recorded “hyperactivity” during mandibular rest a sign of dysfunctional jaw muscle activity and temporomandibular disorders (TMD)?

BackgroundSome authors state that above‐normal surface electromyography (SEMG) levels during mandibular rest (MR) are a general sign of temporomandibular disorders (TMD).ObjectiveThe aim was to compare SEMG levels in the masseter and anterior temporalis areas during MR between patients with disc displacement (DD) and subjects identified as healthy. The hypothesis was that average SEMG levels would be higher in the patients during MR before and after repeated clenches with maximal effort.MethodsThirty‐six healthy subjects, and 42 patients with DD, were included. SEMG levels were recorded bilaterally in the temporalis and masseter areas during MR before clenching and after repeated clenches with maximal effort. Multivariate analysis of variance (MANOVA) was used to compare the means of the log‐transformed SEMG‐values for the subject groups.ResultsThe mean MR levels in the four areas before clenching ranged from −0.19 log (µV) to 1.20 log(µV) in healthy subjects and from −0.22 log(µV) to 0.96 log(µV) in patients. The mean MR levels in the four areas after repeated clenches ranged from −0.19 log (µV) to 1.04 log(µV) in healthy subjects and from −0.27 log(µV) to 0.93 log(µV) in patients. The MANOVA test showed no significant differences in the means for MR for the four areas between the groups at the 5% significance level.ConclusionThe hypothesis that jaw muscle SEMG levels during MR are on average generally higher in TMD patients is not supported. A possible explanation for the previous findings is that activity in other muscles was mislabelled as jaw muscle activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156203/2/joor13032_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156203/1/joor13032.pd

Temporomandibular joint pathosis related to sex, age, and dentition in autopsy material

The purpose of this autopsy study was to test the hypotheses that temporomandibular joint (TMJ) arthrosis is more common in women than in men, increases with age, and is more common in edentulous persons than in those with natural teeth. Two hundred forty-eight TMJs removed at autopsy from 224 fresh cadavers were investigated macroscopically with dissection or cryosectioning. Age was found to be a significant factor in prediction of TMJ arthrosis (p p p p < 0.001) between arthrosis, disk displacement, disk deformation, and disk perforation. There were no statistically significant differences in the prevalence of morphologic changes in the joints from persons with 10 or more natural teeth in each jaw compared with those from persons without natural teeth. The results of this study showed that TMJ arthrosis is more frequent in older than in younger persons. TMJ disk displacement generally appears necessary for the development of perforations. The findings of this study indicate that sex and dentition are not major factors for the development of TMJ pathosis in elderly individuals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31264/1/0000170.pd

A History of Universalism: Conceptions of the Internationality of Science from the Enlightenment to the Cold War

That science is fundamentally universal has been proclaimed innumerable times. But the precise geographical meaning of this universality has changed historically. This article examines conceptions of scientific internationalism from the Enlightenment to the Cold War, and their varying relations to cosmopolitanism, nationalism, socialism, and 'the West'. These views are confronted with recent tendencies to cast science as a uniquely European product

Diagnosis of nonstationary processes using reduced interference time-frequency distribution

This project is focused on the application of the start-of-the-art signal processing techniques to the biomedical applications: diagnostics of TMD (Temporomandibular Joint Disorder). This report starts with the background of the time frequency analysis, followed by the detailed investigation of time frequency properties, which served as the basis of our signal processing algorithms