European journal of oral sciences
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The goals of this study were to investigate whether (i) muscle activities are affected by different feedback strategies, (ii) the balancing behavior of the neuromuscular system is influenced by different force levels, and (iii) axial loading of the posterior teeth is a realistic biomechanical conception. In 10 healthy subjects, all jaw muscles were recorded bilaterally. Intra-oral force transfer and force measurement were achieved by using a measuring device simulating natural maximum intercuspation. ⋯ The results indicate an essential recruitment difference of the jaw muscles between the two clenching conditions. Pure axial loading of teeth seems to be impeded by the anterior force component during bilateral clenching. The posterior movement of the RP might prevent overloading of the temporomandibular joints and anterior teeth.
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The purpose of the study was to examine whether patients' psychosocial profiles differ depending on if the location of pain is in the masticatory muscles, the temporomandibular joint, or both. Eligible participants were 491 consecutive patients examined according to the research diagnostic criteria for temporomandibular disorders (RDC/TMD). Among these a total of 225 adult TMD patients had at least one pain-related TMD diagnosis and were therefore included in this study and completed the multidimensional pain inventory (MPI). ⋯ Although patients with joint pain were significantly more impaired in jaw function, no significant differences in depression, in somatization or in the 11 scales of the MPI were observed. The location of pain in TMD patients is not a major factor for the prediction of psychosocial profiles. Therefore, clinical TMD diagnoses alone form an insufficient basis for tailored behavioural or psychological management.
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In humans, inhibitory jaw reflexes can be depressed by painful stimulation of remote parts of the body. The underlying mechanisms may involve diffuse noxious inhibitory controls (DNIC). Animal experiments have shown that the neurons which may mediate DNIC show spatial encoding (i.e. their responses vary in relation to the size of the body area being stimulated). ⋯ Conditioning stimuli applied to the larger but not to the smaller areas resulted in significant modulations of the reflex. There was a significant correlation between stimulus area and reflex magnitude. These results demonstrate a spatial dependency for the modulation of an inhibitory jaw reflex by painful stimuli -- a further parallel with DNIC as studied on single neurons in animals.
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Randomized Controlled Trial Comparative Study
Effects of an occlusal splint compared with cognitive-behavioral treatment on sleep bruxism activity.
The impact of an occlusal splint (OS) compared with cognitive-behavioral treatment (CBT) on the management of sleep bruxism (SB) has been poorly investigated. The aim of this study was to evaluate the efficacy of an OS with CBT in SB patients. Following a randomized assignment, the OS group consisted of 29, and the CBT group of 28, SB patients. ⋯ The analyses demonstrated a significant reduction in SB activity, self-assessment of SB activity, and psychological impairment, as well as an increase of positive stress-coping strategies in both groups. However, the effects were small and no group-specific differences were seen in any dependent variable. This is an initial attempt to compare CBT and OS in SB patients, and the data collected substantiate the need for further controlled evaluations, using a three-group randomized design with repeated measures to verify treatment effects.
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We have previously carried out detailed characterization and identification of Fos expression within the trigeminal nucleus after tooth pulp stimulation in ferrets. The aim of this study was to determine the effect of pulpal inflammation on the excitability of central trigeminal neurons following tooth pulp stimulation. Adult ferrets were prepared under anesthesia to allow tooth pulp stimulation, recording from the digastric muscle, and intravenous injections at a subsequent experiment. ⋯ All non-stimulated animals showed negligible Fos labeling, with no differences recorded between inflamed and non-inflamed groups. Following tooth pulp stimulation, Fos expression was greater in animals with inflamed teeth than in animals with non-inflamed teeth, with the greatest effect seen in the subnucleus caudalis. These results suggest that inflammation increases the number of trigeminal brainstem neurons activated by tooth pulp stimulation; this may be mediated by peripheral or central mechanisms.