Cranio
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Comparative Study
A comparison of headache symptoms between two groups: a TMD group and a general dental practice group.
Several studies have shown that headaches are associated with patients who have temporomandibular disorders (TMD) compared with non-TMD patients. None of these studies separated the patients by gender or controlled for TMD in the two groups of patients. This study compared a TMD group of patients and a non-TMD group for recent headache symptoms, TMD symptoms and for gender differences. ⋯ The TMD group had greater severity of headaches than the non-TMD group. Dividing the two groups into genders, females also had a greater severity of headaches than male counterparts in the TMD and non-TMD groups. From the multivariate logistic regression analysis, these results indicate that headache symptoms are common in patients with TMD symptoms and that the headaches were more severe in the TMD patients than in the non-TMD patients.
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Comparative Study Clinical Trial
Effect of anterior repositioning splints on the electromyographic activities of masseter and anterior temporalis muscles.
The effect of anterior repositioning (AR) splint therapy on masticatory muscle activity was investigated in seventeen patients with internal derangement; disk displacement with reduction in particular. Integrated electromyography (EMG) recordings from the masseter and anterior temporalis muscles were analyzed quantitatively during maximal biting in intercuspal position before and after eight week treatment period, EMG recordings were taken for each subject prior to the beginning of clinical therapy and final EMG recordings were made without AR splint to provide a standard for comparison. ⋯ Before and after treatment the EMG activity from the masseter muscle was less than from the temporal muscle; 3. AR splint therapy resulted in reduction of the pain (88.2%) and jaw joint sounds (64.7%) and mean vertical opening which was 42.17 mm before treatment increased to 45.06 mm.
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Intramuscular EMG of the lateral pterygoid muscles (LPM), surface EMG of the temporalis and masseter muscles and force measurements of the temporomandibular joint (TMJ) were synchronously used to investigate the biomechanical role of the two heads of the LPM in relation to internal derangement (ID) of the TMJ. EMG and kinetic analysis of five static conditions (resting, protraction, opening, molar and incisor clenching) and three maximum isometric masticatory forces (opening, molar and incisor clenching) were done to compare forces and muscular activity between TMJ ID and control subjects. The analysis of variance results of the integrated linear envelope (LE) EMG showed no significant differences between the two groups for the masseter and temporalis muscles. ⋯ The ILP muscle seemed to have lost its functional specificity. The results of the isometric forces showed that TMJ ID subjects exhibited significantly lower molar bite forces (297.1N over 419N, p = .042) confirming that they have less muscle strength and tissue tolerance than subjects with healthy masticatory muscle systems. A neuromuscular adaptation could be occurring in the TMJ ID masticatory system affecting muscular actions and forces.