Immediate effect of a stabilization splint on masticatory muscle activity in temporomandibular disorder patients.
TL;DR: To verify the static neuromuscular equilibrium of occlusion, EMG activity of left and right temporal and masseter muscles was recorded in all patients and the activity index was computed over a maximum voluntary clench test of 3 s.
Abstract: Surface electromyography (EMG) allows the quantification of the occlusal equilibrium in dysfunctional patients, for instance in those with temporomandibular disorders (TMD). Fourteen patients (ten women, four men) with internal derangement type I were selected among the TMD patients referred to a private practice in Milan. A stabilization splint with posterior contacts was made for each patient. To verify the static neuromuscular equilibrium of occlusion, EMG activity of left and right temporal and masseter muscles was recorded in all patients and the activity (ratio between the activities of the temporal and masseter muscles) index was computed over a maximum voluntary clench test of 3 s. Muscular waveforms were also analysed by computing a percentage overlapping coefficient (POC, an index of the symmetric distribution of the muscular activity determined by the occlusion). The total electrical activity was measured by calculating the area under the entire muscular waveforms. In all patients EMG was performed just before and immediately after the insertion of the splint and data were compared by paired Student's t-tests. Overall, the splint reduced the electrical activity of the analysed muscles (P < 0.005) and made it more equilibrated both between the left and right side (larger symmetry in the masseter muscle POC, P < 0.05) and between the temporal and masseter muscles (activity index, P < 0.01).
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TL;DR: Findings from literature on masticatory function for both healthy persons and patient groups are presented and the influence of oral rehabilitation, e.g. dental restorations, implant treatment and temporomandibular disorder treatment, on masticsatory function will be discussed.
Abstract: Summary During chewing, food is reduced in size, while saliva moistens the food and binds the masticated food into a bolus that can be easily swallowed. Characteristics of the oral system, like number of teeth, bite force and salivary flow, will influence the masticatory process. Masticatory function of healthy persons has been studied extensively the last decades. These results were used as a comparison for outcomes of various patient groups. In this review, findings from literature on masticatory function for both healthy persons and patient groups are presented. Masticatory function of patients with compromised dentition appeared to be significantly reduced when compared with the function of healthy controls. The influence of oral rehabilitation, e.g. dental restorations, implant treatment and temporomandibular disorder treatment, on masticatory function will be discussed. For instance, implant treatment was shown to have a significant positive effect on both bite force and masticatory performance. Also, patient satisfaction with an implant-retained prosthesis was high in comparison with the situation before implant treatment. The article also reviews the neuromuscular control of chewing. The jaw muscle activity needed to break solid food is largely reflexly induced. Immediate muscle response is necessary to maintain a constant chewing rhythm under varying food resistance conditions. Finally, the influence of food characteristics on the masticatory process is discussed. Dry and hard products require more chewing cycles before swallowing than moist and soft foods. More time is needed to break the food and to add enough saliva to form a cohesive bolus suitable for swallowing.
342 citations
TL;DR: Until electromyographic measures are correlated with other multidimensional, especially subjective and pain-related methods, the clinical use of this method for diagnostic purposes of temporomandibular disorders remains in doubt, and is not at present recommended.
Abstract: Several electronic instruments have been developed as adjuncts to objectively record the dysfunctional features of temporomandibular disorders and to study the effectiveness of various treatment interventions. The aim of this review was to assess the value and contribution of clinical electromyographic research in the understanding of asymptomatic and dysfunctional muscle function and the therapeutic effects of interocclusal appliances. For this purpose MedLine and PubMed searches were conducted with the following main keywords alone and in various combinations: electromyography, muscles of mastication, masseter, temporalis, temporomandibular, TMD, utility, validity, repeatability, rest, postural, vertical dimension, occlusal, splint, treatment. The review includes critical evaluation, discussion and conclusions regarding electromyographic studies in asymptomatic and dysfunctional muscles, rest position, occlusal parameters and interocclusal appliances, as well as a critical summary and proposals for further research. Much of earlier critique of many electromyographic studies still applies regarding comparative sample selections, research designs, analyses and conclusions. The areas not well-understood include normal biological variation, capacity for adaptation, fluctuations regarding the clinical course and multidimensional features of temporomandibular disorders and long-term follow-up data, especially in studies that evaluate the effectiveness of therapeutic measures. Considering the required improvements in technical and research designs features and critical appraisal electromyographic research could have value as an adjunct research tool to study features of craniofacial muscle-related dysfunction. Until electromyographic measures are correlated with other multidimensional, especially subjective and pain-related methods, the clinical use of this method for diagnostic purposes of temporomandibular disorders remains in doubt, and is not at present recommended.
126 citations
TL;DR: In this paper, the authors investigated the sensitivity to electrode displacements of amplitude and spectral surface EMG variables, and analyzed if this sensitivity is affected by the inter-electrode distance of the bipolar recording.
Abstract: This study addresses methodological issues on surface electromyographic (EMG) signal recording from jaw elevator muscles. The aims were (i) to investigate the sensitivity to electrode displacements of amplitude and spectral surface EMG variables, (ii) to analyse if this sensitivity is affected by the inter-electrode distance of the bipolar recording, and (iii) to investigate the effect of inter-electrode distance on the estimated amplitude and spectral EMG variables. The superficial masseter and anterior temporalis muscles of 13 subjects were investigated by means of a linear electrode array. The percentage difference in EMG variable estimates from signals detected at different locations over the muscle was larger than 100% of the estimated value. Increasing the inter-electrode distance resulted in a significant reduction of the estimation variability because of electrode displacement. A criterion for electrode placement selection is suggested, with which the sensitivity of EMG variables to small electrode displacements was of the order of 2% for spectral and 6% for amplitude variables. Finally, spectral and, in particular, amplitude EMG variables were very sensitive to inter-electrode distance, which thus should be fixed when subjects or muscles are compared in the same or different experimental conditions.
120 citations
TL;DR: In this article, the right and left masseter and temporalis muscles were measured during maximum teeth clenching in 103 temporomandibular disorders (RDC/TMD) patients, divided into three non-overlapping groups: myogenous, arthrogenous and psycogenous patients.
93 citations
01 Jan 2007
TL;DR: Surface electromyography of the masticatory muscles allowed an objective discrimination among different RDC/TMD subgroups and could assist conventional clinical assessments.
Abstract: The research diagnostic criteria for temporomandibular disorders (RDC/TMD) are used for the classification of patients with temporomandibular disorders (TMD) Surface electromyography of the right and left masseter and temporalis muscles was performed during maximum teeth clenching in 103 TMD patients subdivided according to the RDC/TMD into 3 non-overlapping groups: (a) 25 myogenous; (b) 61 arthrogenous; and (c) 17 psycogenous patients Thirty-two control subjects matched for sex and age were also measured During clenching, standardized total muscle activities (electromyographic potentials over time) significantly differed: 1317mV/mV s % in the normal subjects, 1176mV/mV s % in the myogenous patients, 1053mV/mV s % in the arthrogenous patients, 887mV/mV s % in the psycogenous patients (po0001, analysis of covariance) Symmetry in the temporalis muscles was larger in normal subjects (863%) and in myogenous patients (849%) than in arthrogenous (827%), and psycogenous patients (805%) (p ¼ 0041) No differences were found for masseter muscle symmetry and torque coefficient (p4005) Surface electromyography of the masticatory muscles allowed an objective discrimination among different RDC/TMD subgroups This evaluation could assist conventional clinical assessments r 2007 Elsevier Ltd All rights reserved
92 citations
Cites background or methods from "Immediate effect of a stabilization..."
...Even if the actual role of occlusion in the development of signs and symptoms in patients with TMD is still controversial, in some patients altered occlusal conditions may be a factor in triggering abnormal muscular activity (Ferrario et al., 2002)....
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...…different research diagnostic herapy (2007), doi:10.1016/j.math.2007.05.011 Gross et al., 1996; Sato et al., 1998; Liu et al., 1999; Pinho et al., 2000; Alcantara et al., 2002; Ferrario et al., 2002, 2006b; John et al., 2003; Suvinen et al., 2003; Landulpho et al., 2004; Manfredini et al., 2006)....
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...…of their masticatory function is being used for diagnosis, to monitor the progression of the disease, and to measure the effect of treatment (Visser et al., 1995; Sato et al., 1998; Liu et al., 1999; Pinho et al., 2000; Ferrario et al., 2002, 2006b; John et al., 2003; Suvinen et al., 2003)....
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...Indeed, TMD is more frequently found in women than in men (Ferrario et al., 2002)....
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