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The study assessed masticatory muscle electromyographic (EMG) activity in both children diagnosed with pain-related temporomandibular disorders (TMD-P) and awake bruxism (AB) and in children without TMD, as well as the diagnostic value of surface electromyography (sEMG) in diagnosing TMD-P in subjects with AB. After evaluation based on the Axis I of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), 30 children diagnosed with myofascial pain were included in the myofascial pain group and 30 children without TMD diagnosis comprised the control group (mean age of 9.49 ± 1.34 years). The activity of the anterior temporal (TA) and masseter (MM) muscle was assessed bilaterally using a DAB-Bluetooth device (zebris Medical GmBH, Germany) at rest and during maximum voluntary clenching (MVC). The receiver operating characteristic (ROC) curve was used to determine the accuracy, sensitivity, and specificity of the normalized sEMG data. Statistically significant intergroup differences were observed in TA and MM muscle EMG activity at rest and during MVC. Moderate degree of sEMG accuracy in discriminating between TMD-P and non-TMD children was observed for TAmean, left MM, and MMmean EMG muscle activity at rest. sEMG can be a useful tool in assessing myofascial TMD pain in patients with AB. [ABSTRACT FROM AUTHOR]

This study assessed the electrical activity of the masticatory muscles in both children with down syndrome (DS) and healthy children. After applying the inclusion and exclusion criteria, 30 patients aged between 7.9 and 11.8 years participated in the study. They were divided into two groups of 15: DS and non-DS. A DAB-Bluetooth device (Zebris Medical GmbH, Germany) was used to record the electromyographical (EMG) activity of the right and left temporal and of the right and left masseter muscles at rest and during maximum voluntary clenching (MVC). The asymmetry index between right and left masticatory muscle EMG activity was calculated for each position. The Mann–Whitney U test was applied to analyze the study results. There were no differences in the electrical activity of the temporal and masseter muscles at rest between the groups. During MVC, the asymmetry index for the masseter muscles was significantly higher in subjects with DS. The electrical potentials of the temporal and masseter muscles in children with DS were significantly lower compared to the corresponding parameters for healthy children when clenching. [ABSTRACT FROM AUTHOR]

Immediate adaptation to experimental-balancing interferences is known to affect jaw kinematics and electromyographic activity ( EMG). However, little is known about the influence on masticatory performance parameters. This study hypothesises that balancing-side interferences significantly reduce the performance of the masticatory system. Twenty-one healthy subjects (eleven female, mean age: 24·1 ± 1·2 years) chewed standardised silicone cubes performing 15 masticatory cycles on the right side under three experimental conditions: (i) natural dentition ( ND), (ii) splints with structured occlusal profiles ( SS) (iii) splints with balancing interferences in the left molar region ( OI). The particle size distribution was determined by a validated scanning procedure and curve fitted with the Rosin-Rammler function to determine X50-values. The EMG of both temporalis and masseter muscles was recorded simultaneously, and the total muscle work ( TMW) was calculated. A jaw-tracking device recorded the incisal movement path ( IMP). The functional parameters under the experimental conditions were compared by repeated-measures analysis of variance. The findings confirm our hypothesis. The X50-values differed significantly ( P < 0·01) between ND and OI (4·34 vs. 4·60 mm), and between SS and OI (4·34 vs. 4·60 mm), respectively. In contrast, no significant differences ( P > 0·05) were observed between SS and ND. There was no significant difference in both TMW (1269·0 vs. 1284·9 vs. 1193·9 μV*s) and IMP (720·2 vs. 735·3 vs. 723·1 mm) amongst the three conditions ( P > 0·05). These findings confirm the assumption that the disturbance of the habitual chewing cycles by balancing-side interferences significantly reduces the masticatory performance in the short term. Occlusal balancing-side interferences are common technical failures of dental restorations. Simulation of this condition caused deterioration of masticatory performance in healthy young adults. Further studies should be carried out, on whether the observed effect is long-term and whether masticatory performance decreases even more in patients with reduced adaptive capacity. [ABSTRACT FROM AUTHOR]

Walter MH, Schuette U, Raedel M, Koch R, Wolf B, Scheuch K, Kirch W. Oral health-related quality of life and oral status in a German working population. Eur J Oral Sci 2011; 119: 481-488. © 2011 Eur J Oral Sci The study aim was to identify predictors of impaired oral health-related quality of life (OHRQoL). Employees of five companies were offered a clinical full-mouth examination. Oral health-related quality of life was measured with the German version of the Oral Health Impact Profile (OHIP) and summarized as additive scores (OHIP-ADD) and as prevalence of negative impacts (OHIP-SC). Two logistic regression models were developed for the odds of increased scores of the target variables OHIP-ADD and OHIP-SC. The target variables were dichotomized, and for the OHIP-ADD, the cut-off point for having impaired OHRQoL was heuristically defined as OHIP-ADD > 34. For the OHIP-SC, the corresponding threshold was OHIP-SC > 0. In the model for the OHIP-ADD, female gender, impaired aesthetics, few posterior occluding pairs, and painful masticatory muscles proved to be significant independent variables. For the OHIP-SC, female gender, impaired aesthetics, painful masticatory muscles, joint sounds, missing mandibular teeth, and carious teeth were significant. This cross-sectional study showed that within the models for both OHIP-ADD and OHIP-SC the high-risk person for impaired OHRQoL is a woman with impaired aesthetics and painful masticatory muscles. [ABSTRACT FROM AUTHOR]