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1.
Biochem Eng J ; 176: 108200, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34522158

RESUMEN

In January 2020, the World Health Organization (WHO) identified a new zoonotic virus, SARS-CoV-2, responsible for causing the COVID-19 (coronavirus disease 2019). Since then, there has been a collaborative trend between the scientific community and industry. Multidisciplinary research networks try to understand the whole SARS-CoV-2 pathophysiology and its relationship with the different grades of severity presented by COVID-19. The scientific community has gathered all the data in the quickly developed vaccines that offer a protective effect for all variants of the virus and promote new diagnostic alternatives able to have a high standard of efficiency, added to shorter response analysis time and portability. The industry enters in the context of accelerating the path taken by science until obtaining the final product. In this review, we show the principal diagnostic methods developed during the COVID-19 pandemic. However, when we observe the diagnostic tools section of an efficient infection outbreak containment report and the features required for such tools, we could observe a highlight of electrochemical biosensing platforms. Such devices present a high standard of analytical performance, are low-cost tools, easy to handle and interpret, and can be used in the most remote and low-resource regions. Therefore, probably, they are the ideal point-of-care diagnostic tools for pandemic scenarios.

2.
J Oral Rehabil ; 45(7): 504-511, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29761534

RESUMEN

The objective of this study was to analyse the co-contraction behaviour of jaw and neck muscles during force-controlled experimental grinding in the supine position. Twelve symptom-free subjects were enrolled in the experimental study. Electromyographic (EMG) activity of semispinalis capitis, splenius capitis and levator scapulae muscles was recorded bilaterally with intramuscular fine-wire electrodes, whereas that of sternocleidomastoideus, infrahyoidal, suprahyoidal, masseter and anterior temporalis muscles were registered with surface electrodes. EMG and force measurements were performed during tasks simulating tooth grinding on custom-made intraoral metal splints. The mean EMG activity normalised by maximum voluntary contraction (% MVC) of each of the neck muscles studied during grinding was analysed and compared with previous data from jaw clenching at identical force (100 N) and (supine) position. The occurrence of low-level, long-lasting tonic activation (LLTA) of motor units was also documented. The mean three-dimensional force vector of the grinding forces was 106 ± 74 N. In the frontal plane, the incline to the midsagittal plane ranged between 10° and 15°. In the midsagittal plane, the incline to the frontal plane was negligibly small. Posterior neck muscle activity during grinding ranged between 4.5% and 12% MVC and during clenching with 100 N between 1.8% and 9.9% MVC. Masticatory muscle activity during grinding ranged between 17% and 21% MVC for contralateral masseter and ipsilateral temporalis and between 4% and 6.5% for ipsilateral masseter and contralateral temporalis. LLTA had an average duration of 195 ± 10 seconds. The findings from this study do not support pathophysiological muscle chain theories postulating simple biomechanical coupling of neck and jaw muscles. Co-contractions of neck and masticatory muscles may instead occur as a result of complex neurophysiological interactions.


Asunto(s)
Bruxismo/fisiopatología , Electromiografía , Masticación/fisiología , Músculos Masticadores/fisiopatología , Contracción Muscular/fisiología , Músculos del Cuello/fisiología , Adulto , Fuerza de la Mordida , Femenino , Humanos , Masculino , Posición Supina/fisiología
3.
J Oral Rehabil ; 44(5): 375-384, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28258640

RESUMEN

Although knowledge of short-range kinetic interactions between antagonistic teeth during mastication is of essential importance for ensuring interference-free fixed dental reconstructions, little information is available. In this study, the forces on and displacements of the teeth during kinetic molar biting simulating the power stroke of a chewing cycle were investigated by use of a finite-element model that included all the essential components of the human masticatory system, including an elastic food bolus. We hypothesised that the model can approximate the loading characteristics of the dentition found in previous experimental studies. The simulation was a transient analysis, that is, it considered the dynamic behaviour of the jaw. In particular, the reaction forces on the teeth and joints arose from contact, rather than nodal forces or constraints. To compute displacements of the teeth, the periodontal ligament (PDL) was modelled by use of an Ogden material model calibrated on the basis of results obtained in previous experiments. During the initial holding phase of the power stroke, bite forces were aligned with the roots of the molars until substantial deformation of the bolus occurred. The forces tilted the molars in the bucco-lingual and mesio-distal directions, but as the intrusive force increased the teeth returned to their initial configuration. The Ogden material model used for the PDL enabled accurate prediction of the displacements observed in experimental tests. In conclusion, the comprehensive kinetic finite element model reproduced the kinematic and loading characteristics of previous experimental investigations.


Asunto(s)
Restauración Dental Permanente/métodos , Análisis de Elementos Finitos , Masticación/fisiología , Músculos Masticadores/anatomía & histología , Articulación Temporomandibular/anatomía & histología , Adulto , Vías Aferentes , Fenómenos Biomecánicos , Fuerza de la Mordida , Simulación por Computador , Restauración Dental Permanente/instrumentación , Dentición , Humanos , Imagenología Tridimensional , Cinética , Masculino , Modelos Anatómicos , Ajuste Oclusal , Ligamento Periodontal/anatomía & histología , Estrés Mecánico , Articulación Temporomandibular/fisiología
4.
J Oral Rehabil ; 43(4): 259-68, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26707515

RESUMEN

Strategies for recruitment of masseter muscle motor units (MUs), provoked by constant bite force, for different vertical jaw relations have not previously been investigated. The objective of this study was to analyse the effect of small changes in vertical jaw relation on MU recruitment behaviour in different regions of the masseter during feedback-controlled submaximum biting tasks. Twenty healthy subjects (mean age: 24·6 ± 2·4 years) were involved in the investigation. Intra-muscular electromyographic (EMG) activity of the right masseter was recorded in different regions of the muscle. MUs were identified by the use of decomposition software, and root-mean-square (RMS) values were calculated for each experimental condition. Six hundred and eleven decomposed MUs with significantly (P < 0·001) different jaw relation-specific recruitment behaviour were organised into localised MU task groups. MUs with different task specificity in seven examined tasks were observed. The RMS EMG values obtained from the different recording sites were also significantly (P < 0·01) different between tasks. Overall MU recruitment was significantly (P < 0·05) greater in the deep masseter than in the superficial muscle. The number of recruited MUs and the RMS EMG values decreased significantly (P < 0·01) with increasing jaw separation. This investigation revealed differential MU recruitment behaviour in discrete subvolumes of the masseter in response to small changes in vertical jaw relations. These fine-motor skills might be responsible for its excellent functional adaptability and might also explain the successful management of temporomandibular disorder patients by somatic intervention, in particular by the use of oral splints.


Asunto(s)
Electromiografía , Músculo Masetero/fisiología , Contracción Muscular/fisiología , Reclutamiento Neurofisiológico/fisiología , Análisis de Varianza , Fuerza de la Mordida , Oclusión Dental , Femenino , Voluntarios Sanos , Humanos , Masculino , Músculo Masetero/diagnóstico por imagen , Adulto Joven
5.
J Oral Rehabil ; 42(3): 173-84, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25354425

RESUMEN

Human posture is characterised by inherent body sway which forces the sensory and motor systems to counter the destabilising oscillations. Although the potential of biting to increase postural stability has recently been reported, the mechanisms by which the craniomandibular system (CMS) and the motor systems for human postural control are functionally coupled are not yet fully understood. The purpose of our study was, therefore, to investigate the effect of submaximum biting on postural stability and on the kinematics of the trunk and head. Twelve healthy young adults performed force-controlled biting (FB) and non-biting (NB) during bipedal narrow stance and single-leg stance. Postural stability was quantified on the basis of centre of pressure (COP) displacements, detected by use of a force platform. Trunk and head kinematics were investigated by biomechanical motion analysis, and bite forces were measured using a hydrostatic system. The results revealed that FB significantly improved postural control in terms of reduced COP displacements, providing additional evidence for the functional coupling of the CMS and human posture. Our study also showed, for the first time, that reductions in the sway of the COP were accompanied by reduced trunk and head oscillations, which might be attributable to enhanced trunk stiffness during FB. This physiological response to isometric activation of the masticatory muscles raises questions about the potential of oral motor activity as a strategy to reduce the risk of falls among the elderly or among patients with compromised postural control.


Asunto(s)
Fuerza de la Mordida , Equilibrio Postural/fisiología , Postura/fisiología , Fenómenos Biomecánicos/fisiología , Femenino , Humanos , Masculino , Presión , Adulto Joven
6.
J Appl Microbiol ; 117(1): 266-72, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24684542

RESUMEN

AIMS: To analyse the performance of RT-qPCR using 85B mRNA in the diagnosis of Mycobacterium tuberculosis infection and in the assessment of the response to treatment for pulmonary tuberculosis (TB). METHODS AND RESULTS: Ninety-eight patients with signs of pulmonary TB were selected: 56 were considered infected with Myco. tuberculosis and they had positive cultures or evident clinical response to anti-TB treatment. Patients with pulmonary tuberculosis were evaluated by culture and RT-qPCR for a 30-day specific treatment. It was found that both tests demonstrated a decline in viable bacilli at 15 and 30 days after the beginning of the therapy in most of the patients. The quantification of the 85B mRNA target was performed in 52 patients who had initially shown positive results by RT-qPCR and who were followed on the days 15 and 30 after the specific treatment. Thus 85B mRNA was detectable in sputum samples in 52 patients with a confirmed diagnosis of pulmonary tuberculosis on day 0. During the specific treatment the 85B mRNA was detectable in 13 patients on day 15 and in only three patients on day 30. CONCLUSIONS: Mycobacterium tuberculosis mRNA in the sputum is a useful prognostic marker and its quantification, an early and reliable indicator for monitoring response to treatment, drug resistance, re-infection and relapse. SIGNIFICANCE AND IMPACT OF THE STUDY: RT-qPCR is a tool that can be used in clinical and therapeutic monitoring as an indicator of bacterial resistance and indicator of the period of transmissibility of Myco. tuberculosis in patients with pulmonary TB undergoing treatment.


Asunto(s)
Antituberculosos/uso terapéutico , ADN Bacteriano/genética , Mycobacterium tuberculosis/genética , ARN Bacteriano/genética , ARN Mensajero/genética , Tuberculosis Pulmonar/diagnóstico , Adolescente , Adulto , Anciano , Biomarcadores/metabolismo , ADN Bacteriano/aislamiento & purificación , Monitoreo de Drogas/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , ARN Bacteriano/aislamiento & purificación , ARN Mensajero/aislamiento & purificación , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Esputo/microbiología , Resultado del Tratamiento , Tuberculosis Pulmonar/tratamiento farmacológico , Tuberculosis Pulmonar/microbiología
7.
J Oral Rehabil ; 41(5): 346-52, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24843864

RESUMEN

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 X(50)-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 X(50)-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.


Asunto(s)
Electromiografía , Mandíbula/fisiología , Músculo Masetero/fisiología , Masticación/fisiología , Movimiento/fisiología , Músculo Temporal/fisiología , Adulto , Fenómenos Biomecánicos , Oclusión Dental , Femenino , Humanos , Masculino , Ferulas Oclusales , Rango del Movimiento Articular
8.
J Oral Rehabil ; 41(7): 477-85, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24712837

RESUMEN

Localised motor-unit (MU) recruitment in the masseter was analysed in this study. We investigated whether differential activation behaviour, which has already been reported for distant masseter regions, can also be detected in small muscle subvolumes at the level of single MUs. Two bipolar fine-wire electrodes and an intra-oral 3D bite-force transmitter were used to record intra-muscular electromyograms (EMG) resulting from controlled bite-forces of 10 healthy human subjects (mean age 24.1 ± 1.2 years). Two-hundred and seventeen decomposed MUs were organised into localised MU task groups with different (P < 0.001) force-direction-specific behaviour. Proportions of MUs involved in one, two, three or four examined tasks were 46%, 31%, 18% and 5%, respectively. This study provides evidence of the ability of the neuromuscular system to modify the mechanical output of small masseter subvolumes by differential control of adjacent MUs belonging to distinct task groups. Localised differential activation behaviour of the masseter may be the crucial factor enabling highly flexible and efficient adjustment of the muscle activity in response to complex local biomechanical needs, for example, continually varying bite-forces during the demanding masticatory process.


Asunto(s)
Músculo Masetero/fisiología , Contracción Muscular/fisiología , Reclutamiento Neurofisiológico/fisiología , Adulto , Fuerza de la Mordida , Electrodos , Electromiografía/métodos , Femenino , Humanos , Masculino , Adulto Joven
9.
Int J Comput Dent ; 17(3): 199-218, 2014.
Artículo en Inglés, Alemán | MEDLINE | ID: mdl-25558760

RESUMEN

OBJECTIVES: The primary goal of the present finite element (FE) analysis of a special removable prosthesis, the conical telescopic crown (CTC), was to validate established results based on a rigid model of the CTC and to analyze its characteristic features as a function of the essential material and geometric parameters. Furthermore, the effectiveness of a new element, the composite stop (CS), was investigated. MATERIALS AND METHODS: The study used an axisymmetric FE model containing the inner and outer crown including resin or ceramic veneer, the CS, the cement layer between the interior crown and the tooth, and the upper part of the tooth itself. RESULTS: For a convergence angle (half-cone angle) α = 4 degrees and a moderate chewing force F = 150 N the loosening force decreased from - 50 N without to - 10 N with CS. Increasing α values yielded a decrease of the loosening force. Adherence between the inner (IC) and outer crown (OC) was achieved for all configurations (α = 2 degrees, 4 degrees, and 6 degrees), except for zirconium crowns with α = 6 degrees. In systems without CS, the maximum tensile stress in the veneer increased proportionally to F, but remained limited in those with CS. CONCLUSIONS: The angle a and the coefficient of static friction µ0 emerged as the decisive parameters of the CTC. The computed fitting/loosening behavior agreed well with results of a simple rigid-body model and experiments. The incorporation of a CS allows ceramic veneering of the outer crown. CLINICAL RELEVANCE: The optimal angle α of the CTC is ascribed to a number of customary material combinations for IC and OC. The CS limits the loosening forces of the CTC to values which guarantee non-traumatic removal of the prosthesis.


Asunto(s)
Coronas , Fracaso de la Restauración Dental , Prótesis de Recubrimiento , Análisis de Elementos Finitos , Fenómenos Biomecánicos , Cerámica/química , Aleaciones de Cromo/química , Resinas Compuestas/química , Simulación por Computador , Aleaciones Dentales/química , Adaptación Marginal Dental , Materiales Dentales/química , Diseño de Prótesis Dental , Coronas con Frente Estético , Aleaciones de Oro/química , Humanos , Masticación/fisiología , Modelos Biológicos , Estrés Mecánico , Propiedades de Superficie , Resistencia a la Tracción , Titanio/química , Cemento de Fosfato de Zinc/química , Circonio/química
10.
J Appl Microbiol ; 114(4): 1103-8, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23279625

RESUMEN

AIM: Evaluate the IS6110-Taqman system performance in sputum samples from patients with pulmonary tuberculosis from health services in north-eastern Brazil as a diagnostic laboratory tool for pulmonary tuberculosis. METHODS AND RESULTS: 165 sputum samples from respiratory symptomatic patients were evaluated in the IS6110-TaqMan assay: 66 patients with pulmonary tuberculosis and 99 without TB. When the IS6110-TaqMan assay was evaluated using culture and/or clinical response to the specific treatment as the gold standard, IS6110-TaqMan assay obtained a sensitivity of 87.9% and specificity of 98%. The performance of IS6110-TaqMan assay was also evaluated with the sputum smear microscopy, resulting in a sensitivity of 79.7% and specificity 94.8%. CONCLUSIONS: The IS6110-TaqMan was rapid, sensitive and specific for the diagnosis of pulmonary TB. SIGNIFICANCE AND IMPACT OF THE STUDY: IS6110-TaqMan assay is a promising auxiliary tool for the diagnosis of pulmonary TB when used in conjunction with routine laboratory tests, clinical and epidemiological criteria of the patient, thus increasing the sensitivity and specificity of diagnosis.


Asunto(s)
Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Esputo/microbiología , Tuberculosis Pulmonar/diagnóstico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Brasil , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis , Sensibilidad y Especificidad , Adulto Joven
11.
Clin Oral Investig ; 17(1): 259-67, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22302454

RESUMEN

OBJECTIVES: A key aspect of complex restorative therapy is reconstruction of a new three-dimensional jaw relation. The objective of this study was to test the hypotheses that the initially recorded jaw relation would deviate substantially from the jaw position of the prosthetic reconstruction and that activity ratios of the jaw muscles would be significantly different for each of these jaw positions. MATERIALS AND METHODS: In 41 healthy subjects, 41 examiners incorporated intraoral occlusal devices fabricated with all the technical details and procedures commonly used during prosthetic reconstructions. The jaw positions in centric relation with the incorporated occlusal devices were telemetrically measured in the condylar, first molar and incisal regions, relative to intercuspation. Electromyographic (EMG) activity of the temporalis and masseter muscles was recorded, and activity ratios were calculated for homonymous and heteronymous muscles. RESULTS: The recorded jaw relation differed significantly (p < 0.001) from the jaw position reconstructed with the intraoral occlusal devices. The initially recorded jaw relation was reproduced with the intraoral occlusal device with spatial accuracy of approximately 0.3 mm in the condylar, molar and incisal regions. The EMG ratios between centric relations and the reconstructed positions were significantly different (p < 0.05) for the temporal muscle and the temporalis/masseter ratio. CONCLUSIONS: The findings revealed that three-dimensional jaw-relation recording may be reproduced in a simulated prosthetic reconstruction within the accuracy reported for replicate intraoral bite recordings. CLINICAL RELEVANCE: Centric relation recordings may be reproduced in a prosthetic reconstruction with the spatial accuracy of 0.3 mm.


Asunto(s)
Diseño de Prótesis Dental , Registro de la Relación Maxilomandibular/métodos , Resinas Acrílicas/química , Relación Céntrica , Articuladores Dentales , Materiales de Impresión Dental/química , Oclusión Dental Céntrica , Electromiografía , Femenino , Humanos , Imagenología Tridimensional/métodos , Incisivo/anatomía & histología , Registro de la Relación Maxilomandibular/instrumentación , Masculino , Mandíbula/anatomía & histología , Cóndilo Mandibular/anatomía & histología , Músculo Masetero/fisiología , Metilmetacrilatos/química , Modelos Dentales , Diente Molar/anatomía & histología , Contracción Muscular/fisiología , Telemetría/instrumentación , Músculo Temporal/fisiología , Interfaz Usuario-Computador , Adulto Joven
12.
Schmerz ; 27(3): 243-52, 2013 Jun.
Artículo en Alemán | MEDLINE | ID: mdl-23695155

RESUMEN

Besides the different forms of odontalgia, myalgias of the masticatory muscles are the most frequent noninfectious complaints in the orofacial region. After summarizing the recommendations set forth by the Interdisciplinary Working Group of Orofacial Pain within the German Chapter of the IASP (German Pain Society), we present the current state of knowledge regarding the etiology, diagnosis, and therapeutic options, based on an extensive literature search. A systematic literature search was carried out in PubMed, the Cochrane Library, and the database of the Deutsche Zahnärztliche Zeitschrift. The results corroborate our previous recommendations that for the majority of patients pain reduction or pain relief can be achieved with noninvasive, reversible methods. Short- and long-term trials have added more evidence to the fact that different therapeutic measures have similar efficacy. In patients with chronic myalgias of the jaw muscles, involvement of a psychotherapist is crucial. Patient education, oral appliances, physiotherapeutic exercises, and acupuncture are recommended therapeutic measures, while physical therapy, pharmacotherapy, and psychological therapy received a limited recommendation.


Asunto(s)
Dolor Crónico/terapia , Dolor Facial/terapia , Músculos Masticadores , Mialgia/terapia , Manejo del Dolor/métodos , Dolor Crónico/diagnóstico , Dolor Crónico/etiología , Terapia Combinada , Conducta Cooperativa , Dolor Facial/diagnóstico , Dolor Facial/etiología , Humanos , Comunicación Interdisciplinaria , Mialgia/diagnóstico , Mialgia/etiología , Grupo de Atención al Paciente , Psicoterapia
13.
Int J Comput Dent ; 16(2): 119-23, 2013.
Artículo en Inglés, Alemán | MEDLINE | ID: mdl-23930574

RESUMEN

The third part of this literature review on the clinical relevance of surface electromyography (EMG) of the masticatory muscles summarizes the results of clinical studies in patients with temporomandibular disorders (TMD), preferably randomized controlled trials, examining the impact of changes to the dynamic occlusion. Clenching in left and right laterotrusive positions results in decrease in EMG activity of masseter and temporalis muscles on both working and non-working side. Masseter muscle exhibits largely uniform bilateral activity in laterotrusive positions, independent of canine guidance or group function with and without non-working side contacts. There is a dominance of temporalis muscle activity on the working side and, in case of posterior contacts and balancing contacts, temporalis muscle activity increases and changes from an unilateral to a symmetrical pattern.


Asunto(s)
Oclusión Dental , Electromiografía/métodos , Músculos Masticadores/fisiopatología , Trastornos de la Articulación Temporomandibular/fisiopatología , Humanos , Músculo Masetero/fisiopatología , Contracción Muscular/fisiología , Ensayos Clínicos Controlados Aleatorios como Asunto , Músculo Temporal/fisiopatología
14.
Int J Comput Dent ; 16(1): 37-58, 2013.
Artículo en Inglés, Alemán | MEDLINE | ID: mdl-23641663

RESUMEN

The second part of this review of the literature on the clinical significance of surface electromyography (EMG) of the masticatory muscles systematically examines the results of clinical studies in patients with temporomandibular disorders (TMD), preferably randomized controlled trials, investigating relevant aspects of EMG activity during prolonged chewing activity (fatigue effects), during the mastication process, and under the influence of different factors. Studies on the influence of factors such as gender, age, tooth status, orofacial morphology and (acute) pain, the significance of different occlusal relationships during static and dynamic occlusion, and the impact of changes in static occlusion on EMG activity of the masticatory muscles were included in the review.


Asunto(s)
Electromiografía/métodos , Masticación/fisiología , Músculos Masticadores/fisiopatología , Fatiga Muscular/fisiología , Trastornos de la Articulación Temporomandibular/fisiopatología , Oclusión Dental , Humanos , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Riesgo
15.
J Oral Rehabil ; 39(7): 502-12, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22486535

RESUMEN

The relationship between the dental occlusion and temporomandibular disorders (TMDs) has been one of the most controversial topics in the dental community. In a large epidemiological cross-sectional survey - the Study of Health in Pomerania (Germany) - associations between 15 occlusion-related variables and TMD signs or symptoms were found. In other investigations, additional occlusal variables were identified. However, statistical associations do not prove causality. By using Hill's nine criteria of causation, it becomes apparent that the evidence of a causal relationship is weak. Only bruxism, loss of posterior support and unilateral posterior crossbite show some consistency across studies. On the other hand, several reported occlusal features appear to be the consequence of TMDs, not their cause. Above all, however, biological plausibility for an occlusal aetiology is often difficult to establish, because TMDs are much more common among women than men. Symptom improvement after insertion of an oral splint or after occlusal adjustment does not prove an occlusal aetiology either, because the amelioration may be due to the change of the appliance-induced intermaxillary relationship. In addition, symptoms often abate even in the absence of therapy. Although patients with a TMD history might have a specific risk for developing TMD signs, it appears more rewarding to focus on non-occlusal features that are known to have a potential for the predisposition, initiation or perpetuation of TMDs.


Asunto(s)
Maloclusión , Trastornos de la Articulación Temporomandibular , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Causalidad , Niño , Femenino , Humanos , Masculino , Maloclusión/complicaciones , Maloclusión/epidemiología , Persona de Mediana Edad , Factores de Riesgo , Factores Sexuales , Trastornos de la Articulación Temporomandibular/complicaciones , Trastornos de la Articulación Temporomandibular/epidemiología , Adulto Joven
16.
J Oral Rehabil ; 39(5): 338-48, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22220913

RESUMEN

Aim of this study was to introduce a feasible and valid technique for the assessment of masticatory performance that is comparable to the standard sieving method. Twenty-one chewing samples (Optosil) comminuted by healthy dentate adults were analysed with a sieving and scanning method. Scanning was performed using a conventional flatbed scanner (1200dpi). All scanned images underwent image analysis (ImageJ), which yielded descriptive parameters such as area, best-fitting ellipse for each particle. Of the 2D-image, a volume was estimated for each particle, which was converted into a weight. To receive a discrete distribution of particle sizes comparable to sieving, five chewing samples were used to calculate a size-dependent area-volume-conversion factor. The sieving procedure was carried out with a stack of 10 sieves, and the retained particles per sieve were weighed. The cumulated weights yielded by either method were curve-fitted with the Rosin-Rammler distribution to determine the median particle size x(50) . The Rosin-Rammler distributions for sieving and scanning resemble each other. The distributions show a high correlation (0·919-1·0, n= 21, P<0·01, Pearson's correlation coefficient). The median particle sizes vary between 3·83 and 4·77mm (mean: 4·31) for scanning and 3·53 and 4·55mm (mean: 4·21) for sieving. On average, scanning overestimates the x(50) values by 2·4%. A modified Bland-Altman plot reveals that 95% of the x(50) values fall within 10% of the average x(50) . The scanning method is a valid, simple and feasible method to determine masticatory performance.


Asunto(s)
Masticación/fisiología , Tamaño de la Partícula , Adulto , Estudios de Factibilidad , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Óptica y Fotónica , Reproducibilidad de los Resultados , Siliconas , Adulto Joven
17.
Int J Comput Dent ; 15(4): 297-314, 2012.
Artículo en Inglés, Alemán | MEDLINE | ID: mdl-23457900

RESUMEN

Based on a comprehensive computerized literature search supplemented by a specific manual search of the literature, the present review article focuses on concrete aspects of the application of surface electromyography (EMG) for evaluation of the masticatory muscles in general and of the masseter and anterior temporal muscles in particular, and presents the current base of knowledge on the clinical relevance of surface EMG in dental applications. In the first stage of the review, publications from the year 2000 or later reporting the results of controlled clinical trials (randomized as far as available) of patients with craniomandibular or temporomandibular disorders (TMD) were analyzed. Data from the selected publications were systematically compiled and divided into subject areas as follows: Resting activity, maximal and sub-maximal voluntary contraction, symmetry of EMG activity, and fatigue effects; EMG activity during mastication, factors (including pain) that affect EMG activity, and the impact of adjusting static and dynamic occlusal relationships; Effects of occlusal splints and other occlusal treatments. Surface electromyography is in principle a suitable tool for neuromuscular function analysis in the field of dentistry. If used according to the specific recommendations and in conjunction with a thorough and conscientious clinical history and physical examination, surface EMG measurements can provide objective, documentable, valid, and reproducible data on the functional condition of the masticatory muscles of an individual patient.


Asunto(s)
Electromiografía , Músculos Masticadores/fisiología , Trastornos de la Articulación Temporomandibular/fisiopatología , Articulación Temporomandibular/fisiología , Humanos , Contracción Muscular , Ferulas Oclusales
18.
J Oral Rehabil ; 38(12): 912-20, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21569075

RESUMEN

Neuromuscular adaptations during skill acquisition have been extensively investigated for skeletal muscles. Motor rehabilitation is the main target for application of motor training. Such measures are also relevant for the musculature of the jaw, but few data are available for motor adaptation of the masticatory system. The objective of this study was to evaluate and compare long-term training effects of different motor tasks on masseter and temporal muscles. In 20 healthy subjects, the electromyographic response to unilateral and bilateral maximum voluntary tooth clenching, balancing the mandible on a hydrostatic system under force-feedback-controlled conditions, and unilateral chewing was investigated in an initial session and then in two follow-up sessions separated by 2 and 10 weeks from baseline. Motor tasks were repeated three times for chewing, nine times for maximum biting (MB) and 24 times for the coordination tasks (CT). The sequences of the various motor tasks were applied once in the first session and twice in the second and third sessions. No effects of training were observed for MB tasks except for MB in intercuspation, for which significant yet transient avoidance behaviour occurred in the second session. No significant effects were found for chewing tests. For the CT, however, a robust significant long-term training effect was detected which reduced the electric muscle activity in session 2 by approximately 20% and in session 3 by approximately 40% compared with the initial measurements. The study showed that the masticatory muscles are remarkably prone to motor adaptation if demanding CT must be accomplished.


Asunto(s)
Fuerza de la Mordida , Electromiografía , Ejercicio Físico/fisiología , Masticación/fisiología , Contracción Muscular/fisiología , Femenino , Humanos , Masculino , Resultado del Tratamiento , Adulto Joven
19.
J Oral Rehabil ; 38(10): 729-36, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21385200

RESUMEN

Alterations of body sway caused by isometric contractions of the jaw muscles have been reported previously. The objective of this study was to test if motor tasks of the masticatory system with different control demands affect body posture differently during quiet stance. Position and sway displacements of the center of foot pressure (COP) were measured for 20 healthy subjects who either kept the mandible at rest or performed unilateral and bilateral maximum voluntary teeth clenching, feedback-controlled biting tasks at submaximum bite forces, or unilateral chewing. Two weeks later the measurements were repeated. Compared with quiet stance, the COP results revealed significant changes during the feedback-controlled biting tasks. Robust sway reduction and anterior displacement of the COP were observed under these conditions. Body oscillations were not significantly affected by maximum bites or by unilateral chewing. For most of the variables investigated there were no significant differences between unilateral and bilateral biting. Robust sway reduction during feedback-controlled biting tasks in healthy subjects involved a stiffening phenomenon that was attributed to the common physiological repertoire of posture control, and might optimize the stability of posture under these conditions.


Asunto(s)
Contracción Isométrica/fisiología , Maxilares/fisiología , Equilibrio Postural/fisiología , Desempeño Psicomotor/fisiología , Adulto , Fuerza de la Mordida , Electromiografía , Femenino , Humanos , Masculino , Valores de Referencia
20.
Scand J Immunol ; 72(5): 460-8, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21039742

RESUMEN

Diagnostic tests for tuberculosis (TB) using interferon gamma (IFN-γ) responses produced by T lymphocytes after stimulation by early secretory antigen target 6 (ESAT-6), culture filtrate protein 10 (CFP-10) or purified protein derivate (PPD) were carried out using ELISA (enzyme-linked immunosorbent assay) in whole blood culture supernatants from children with suspected TB disease (n=21), latent TB infection (LTBI; n=17) and negative controls (NC; n=21) from Recife, Pernambuco, Brazil. The results were analysed using the ROC (receiver operating characteristic) curves and the areas under the curve (AUC) generated varied from 0.5 to 1.0 with higher values indicating increased discriminatory ability. Comparisons of AUCs were made using non-parametric assumptions, and the differences were considered significant if P<0.05. The ROC curve showed a statistical difference (P = 0.015) between the LTBI and NC groups with an AUC of 0.731, TB disease and NC (AUC=0.780; P=0.002) and a group with TB (latent infection+disease, n=38) and NC (AUC=0.758; P = 0.001) when the antigen used was ESAT-6. No statistical difference was found between the groups when CFP-10 or PPD was used. In conclusion, the ESAT-6 test may be the most appropriate for diagnosis of childhood TB, both LTBI and TB disease, when associated with epidemiological and clinical data, especially in endemic areas such as Brazil.


Asunto(s)
Antígenos Bacterianos/inmunología , Proteínas Bacterianas/inmunología , Tuberculosis/diagnóstico , Adolescente , Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Brasil/epidemiología , Niño , Preescolar , Enfermedades Endémicas , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Interferón gamma/metabolismo , Masculino , Proteínas Recombinantes/inmunología , Sensibilidad y Especificidad , Linfocitos T/inmunología , Linfocitos T/metabolismo , Tuberculosis/epidemiología , Tuberculosis/inmunología
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