Application of 3D Electromagnetic Articulography in Dentistry: Mastication and Deglutition Analysis. Protocol Report / Aplicación de la Articulografía Electromagnética 3D en Odontología: Análisis de la Masticación y Deglución. Reporte de Protocolo

ABSTRACT: The Stomatognathic System (SS) is an integrated and coordinated morphofunctional unit, consisting of skeletal, muscular, angiological, nervous, glandular and dental structures that work in harmony to perform different functions such as chewing, swallowing, speaking, breathing, tasting and esthetics. The study of SS physiology is crucial to achieving a correct maintenance of its normal function or restoration. Thus, we developed a protocol to record mandibular movement, chewing and swallowing (saliva and water) by using the 3D-electromagnetic articulograph AG501 at the Oral Physiology Laboratory of the Research Centre for Dental Sciences (CICO). This tool has been used for decades in speech and phonetic research and it is able to record, present and evaluate articulated structure movement data in real time. The articulograph provides an ordered data matrix (values ??for the x, y, z axes, among others) for the recorded movement, which is stored in binary files that can be processed by different software. One of these is MATLAB®, allowing us to perform a quick, clear and understandable analysis. The existence of a standardized methodology for recording allows an accurate description of the stages to perform different types of measurements according to the researcher's objective. This has opened the way for a new type of oral physiology analysis based on study reproducibility, which is considered one of the bases of scientific methodology.

RESUMEN: El Sistema Estomatognático es una unidad morfo-funcional integrada y coordinada, constituida por estructuras esqueléticas, musculares, angiológicas, nerviosas, glandulares y dentales que actúan en armonía para realizar diferentes funciones como la masticación, deglución, fonoarticulación, respiración, degustación y estética. Es importante el estudio de la fisiología del SE para lograr un correcto mantenimiento de su función normal, o para la restauración de este. Es así como en el Laboratorio de Fisiología Oral del Centro de Investigación en Ciencias Odontológicas (CICO) hemos desarrollado un protocolo para el registro del movimiento mandibular, masticación y deglución (saliva y agua), utilizando el articulógrafo electromagnético 3D AG501, el cual ha sido utilizado desde hace décadas en la investigación del habla y la fonética y que es capaz de grabar, presentar y evaluar en tiempo real datos del movimiento de estructuras articuladas. El articulógrafo provee de una matriz de datos ordenados (valores para los ejes x, y, z, entre otros) para el movimiento registrado, el cual se almacena en archivos binarios que pueden procesarse a través de diferentes softwares. Uno de ellos es MATLAB®, el cual nos permite realizar un análisis de forma rápida, clara y comprensible. La existencia de una estandarización metodológica de registro, permite describir de forma exacta las etapas para llevar a cabo distintos tipos de mediciones según el objetivo del investigador. De esta forma se abre la puerta a una nueva forma de análisis en la fisiología oral que se sustenta en la reproducibilidad de la investigación que es considerada una de las bases de la metodología científica.

Impact of temporomandibular disorders on the stomatognathic system in children

Background: To evaluate the EMG activity and thickness of right masseter (RM), left masseter (LM), right temporal (RT) and left temporal (LT) muscles and bite force in children with temporomandibular disorders (TMD). Material and Methods: Forty five children (mean age 8.8 years; 22 boys and 23 girls) were examined on the basis of the RDC/TMD and the Faces Pain Scale-Revised (FPS-R) was used to determine the level of severity of the signs and symptoms of TMD, resulting in four groups: GI - without TMD (n=10); GII - with mild TMD (n=18), GIII: with moderate TMD (n=12) and GIV: with severe TMD (n=5). The data of electromyographic activity, maximum bite force and muscle thickness were tabulated and submitted to statistical analysis (ANOVA, P≤0.05). Results: Children with TMD signs and symptoms had lower EMG activity than children of the control group. There was significant difference among the groups for the LT at rest (P=0.01), right (P=0.03) and left (P=0.05) laterality, and for the LM (P=0.01) and LT (P=0.03) muscles in maximum voluntary contraction. There were no statistically significant differences among the groups regarding muscle thickness. The bite force was lower in the TMD groups than children of the control group, with significant statistical difference for the right region (P=0.03). Conclusions: The severity of TMD signs and symptoms affected the EMG activity and the molar bite force in children. However, structural changes in the thickness of masticatory muscles are not perceptible in children with TMD signs and symptoms (AU)

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Systematic Standardized and Individualized Assessment of Masticatory Cycles Using Electromagnetic 3D Articulography and Computer Scripts.

Masticatory movements are studied for decades in odontology; a better understanding of them could improve dental treatments. The aim of this study was to describe an innovative, accurate, and systematic method of analyzing masticatory cycles, generating comparable quantitative data. The masticatory cycles of 5 volunteers (Class I, 19 ± 1.7 years) without articular or dental occlusion problems were evaluated using 3D electromagnetic articulography supported by MATLAB software. The method allows the trajectory morphology of the set of chewing cycles to be analyzed from different views and angles. It was also possible to individualize the trajectory of each cycle providing accurate quantitative data, such as number of cycles, cycle areas in frontal view, and the ratio between each cycle area and the frontal mandibular border movement area. There was a moderate negative correlation (-0.61) between the area and the number of cycles: the greater the cycle area, the smaller the number of repetitions. Finally it was possible to evaluate the area of the cycles through time, which did not reveal a standardized behavior. The proposed method provided reproducible, intelligible, and accurate quantitative and graphical data, suggesting that it is promising and may be applied in different clinical situations and treatments.

Influence of mandibular tori on stomatognathic system function.

OBJECTIVES: To verify the influence of prominent mandibular tori on the functioning of the stomatognathic system. METHODS: The participants included 40 individuals, divided into two groups: those with mandibular tori (GI group: 20 subjects) and those without mandibular tori (GII group: 20 subjects). The authors used the Myosystem-Br1 electromyography system to analyze electromyographic (EMG) activity. For muscle thickness, images of the masseter and temporalis muscles were captured using the NanoMaxx ultrasound. The maximal molar bite force was obtained by means of the Kratos digital dynamometer. RESULTS: The EMG activity was higher in the masseter muscles in the GI group, compared with the GII group, in all clinical conditions assessed except for the mandibular at rest. In dynamic conditions, this higher EMG activity was also observed in the temporalis muscles. The GI group presented significantly less temporalis muscle thickness than seen in the GII group. The maximal bite force was significantly higher in the GI group. CONCLUSIONS: Mandibular tori promoted morphological and functional changes in the stomatognathic system.

Three-dimensional modeling of an individualized functional masticatory system and bite force analysis with an orthodontic bite plate.

PURPOSE: Orthodontic tooth movement is affected by bite forces generated from the masticatory system. This study aims to study three-dimensional (3D) modeling of the individualized functional masticatory system and explore its application in orthodontics. METHODS: An individualized masticatory system model containing the craniomaxilla, mandible, 4 pairs of primary masticatory muscles and complete dentition, including roots and precise dental crowns, was developed using 3D images from spiral computed tomography and digital casts. By registering global coordinates and using data transformation, individual movement data for mandibular opening, lateral excursion and protrusion were recorded with an Arcus Digma system and applied to this model to simulate the functional movements of the mandible. Using the finite element method, deformations and displacement of the masticatory muscles were simulated along with the mandibular movements. Under individualized muscle loading, the bite forces of the lower incisors with the orthodontic bite plate were analyzed. RESULTS: Individualized mandibular movements were simulated, and the performance of the masticatory muscles along with the mandibular movements was measured. The bite force generated on the lower incisors with different thicknesses and the orientations of the orthodontic bite plate were acquired. CONCLUSION: An individualized 3D masticatory system model was constructed using advanced 3D data processing software that integrated 3D images from different sources. Individualized mandibular movement and masticatory muscle performance were simulated using this model. The analysis of the bite force generated on the lower incisors with the orthodontic bite plate suggested that a thickness of 3 mm may be appropriate for clinical use.

[Today's importance of ultrasound in ENT]. / Importance de l'échographie en ORL à l'heure actuelle.

Since ultrasound has been established for diagnosis in ENT several new techniques have been introduced. But also ultrasonography has technically developed and thus has earned even more importance and indications. This was to be shown by this paper as well as the advantages and pitfalls. Ultrasound is quite useful in inflammatory, infectious and tumor pathology in order to make a better diagnosis or staging and to help the surgeon for punture or incision of a pathologic lesion (cytology, bacteriology, drainage). Especially in ENT oncology and post-treatment follow up ultrasound is a very precious technique. Ultrasound can be realized by the ENT specialist himself anywhere and at any time. It is a non aggressive, non invasive technique and its cost is relatively low. Unfortunately by itself it is not very performant to distinguish benign and malignant lesions. But its specificity can be considerably enhanced by combinating it with cytology (UGFNAB, ultrasound guided fine needle aspiration biopsy). Another important field of ultrasound is the examination of salivary glands.

Computed tomography and magnetic resonance imaging of lesions at masticator space.

We aim to review the normal anatomy and imaging appearance of masticator space lesions. Because the masticator space is not amenable to direct examination, cross-sectional imaging with computed tomography and magnetic resonance imaging play an important role in diagnosis and characterization of lesions occurring there. Masticator space lesions can be classified on the basis of their origin into the following categories: inflammatory lesions, benign tumors, malignant tumors, vascular lesions, and developmental lesions. A diverse spectrum of malignant tumors and benign lesions are seen extending from the adjacent spaces. In addition, one should also be familiar with pseudolesions as well as post-treatment changes in the masticator space that can be mistaken for pathologic conditions.

Exploring CBCT-based DICOM files. A systematic review on the properties of images used to evaluate maxillofacial bone grafts.

Previous studies suggests that cone beam computerized tomography (CBCT) images could provide reliable information regarding the fate of bone grafts in the maxillofacial region, but no systematic information regarding the standardization of CBCT settings and properties is available, i.e., there is a lack of information on how the images were generated, exported, and analyzed when bone grafts were evaluated. The aim of this study was to (1) do a systematic review on which type of CBCT-based DICOM images have been used for the evaluation of the fate of bone grafts in humans and (2) use a software suggested in the literature to test DICOM-based data sets, exemplifying the effect of variation in selected parameters (windowing/contrast control, plane definition, slice thickness, and number of measured slices) on the final image characteristics. The results from review identified three publications that used CBCT to evaluate maxillofacial bone grafts in humans, and in which the methodology/results comprised at least one of the expected outcomes (image acquisition protocol, image reconstruction, and image generation information). The experimental shows how the influence of information that was missing in the retrieved papers, can influence the reproducibility and the validity of image measurements. Although the use of CBCT-based images for the evaluation of bone grafts in humans has become more common, this does not reflect on a better standardization of the developed studies. Parameters regarding image acquisition and reconstruction, while important, are not addressed in the proper way in the literature, compromising the reproducibility and scientific impact of the studies.

The masticator space. Value of computed tomography and magnetic resonance imaging in localisation and characterisation of lesions.

Aim of the study was to assess the different roles of magnetic resonance imaging and computed tomography in the evaluation of anatomical origin and pathological nature of lesions involving the masticator space. Overall 41 cases (31 computed tomography and 14 magnetic resonance imaging) of lesions involving masticator space were retrospectively reviewed by two experienced radiologists in consensus. Reference standards were histopathological results and clinical-radiological follow-up after one year. Both computed tomography and magnetic resonance imaging were performed with and without intravenous injection of contrast. Computed tomography and magnetic resonance imaging were correct in identifying the space of origin of lesions respectively in 96% and 92% of cases. Computed tomography correctly diagnosed the nature of lesions in 81% of cases and magnetic resonance imaging in 93% of cases; computed tomography and magnetic resonance imaging correctly characterized, respectively, 88% and 100% of malignant lesions and, respectively, 73% and 83% of benign lesions. In conclusion both computed tomography and magnetic resonance imaging were effective in the identification of the origin of non-extensive lesions involving masticator space. Computed tomography was more precise in depicting lesions originating from masticator space, while magnetic resonance imaging was more correct in depicting lesions originating from contiguous spaces and involving secondarily the masticator space. Magnetic resonance imaging should always be preferred to characterise lesions, nevertheless computed tomography should be chosen in cases with suspected inflammatory involvement of mandible bone.

Evaluation of solid lesions affecting masticator space with diffusion-weighted MR imaging.

OBJECTIVE: The aim of this study was to evaluate the value of diffusion-weighted magnetic resonance (MR) imaging in differentiating various masticator-space solid lesions. STUDY DESIGN: Before surgery and/or pathologic verification, diffusion-weighted echo-planar MR imaging was performed on 78 subjects who had lesions in their masticator spaces. Based on their pathologic outcomes, lesions were classified into 3 groups: group 1: benign tumors and tumor-like lesions (23 cases); group 2: inflammatory diseases (14 cases); and group 3: malignant tumors (41 cases). Mean apparent diffusion coefficients (ADCs) were calculated from diffusion-weighted MR images that were obtained with a b factor of 0 and 1,000 s/mm(2). Differences between groups and lesion types were statistically compared with the Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The ADCs were significantly different (P = .0001) among the 3 groups, between group 1 (1.52 +/- 0.29 [SD] x 10(-3) mm(2)/s) and group 2 (1.01 +/- 0.31 x 10(-3) mm(2)/s), and between group 1 and group 3 (1.11 +/- 0.29 x 10(-3) mm(2)/s). There was no statistically significant difference (P = .31) in ADCs between group 2 and group 3. In addition, there were significant differences between osteosarcomas (1.40 +/- 0.28 x 10(-3) mm(2)/s) and inflammatory diseases (P = .038) and between osteosarcomas and carcinomas (1.11 +/- 0.26 x 10(-3) mm(2)/s; P = .035). CONCLUSIONS: Diffusion-weighted MR imaging may be valuable in differentiating between benign solid lesions and malignant tumors in the masticator space. Inflammatory lesions cannot, however, be separated from most malignant tumors, except for osteosarcomas.

Functional implications of dicynodont cranial suture morphology.

Cranial suture morphology of Lystrosaurus and the generalized dicynodont Oudenodon was investigated to determine the strain environment during mastication, which in turn may indicate a difference in cranial function between the two taxa. Finite element (FE) analysis indicated that less strain accumulated in the cranium of Lystrosaurus during orthal bite simulations than in Oudenodon. Despite the overall difference in strain magnitude, moderate to high FE-predicted strain accumulated in similar areas of the cranium of both taxa. The suture morphology in these cranial regions of Lystrosaurus and Oudenodon was investigated further by examination of histological sections and supplemented by observations of serial sections and computed tomography (CT) scans. The predominant type of strain from selected blocks of finite elements that contain sutures was determined, enabling comparison of suture morphology to strain type. Drawing from strain-suture correlations established in extant taxa, the observed patterns of sutural morphology for both dicynodonts were used to deduce cranial function. The moderate to high compressive and tensile strain experienced by the infraorbital bar, zygomatic arch, and postorbital bar of Oudenodon and Lystrosaurus may have been decreased by small adjustive movements at the scarf sutures in those regions. Disparities in cranial suture morphology between the two taxa may reflect differences in cranial function. For instance, the tongue and groove morphology of the postorbital-parietal suture in Oudenodon could have withstood the higher FE-predicted tensile strain in the posterior skull roof. The scarf premaxilla-nasal suture of Lystrosaurus provided an additional region of sutural mobility in the anterior surface of the snout, suggesting that Lystrosaurus may have employed a different biting regime than Oudenodon. The morphology of several sutures sampled in this study correlated with the FE-predicted strain, although other cranial functional hypotheses remain to be tested.

Cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial region: a systematic review of the literature.

This study reviewed the literature on cone-beam computerized tomography (CBCT) imaging of the oral and maxillofacial (OMF) region. A PUBMED search (National Library of Medicine, NCBI; revised 1 December 2007) from 1998 to December 2007 was conducted. This search revealed 375 papers, which were screened in detail. 176 papers were clinically relevant and were analyzed in detail. CBCT is used in OMF surgery and orthodontics for numerous clinical applications, particularly for its low cost, easy accessibility and low radiation compared with multi-slice computerized tomography. The results of this systematic review show that there is a lack of evidence-based data on the radiation dose for CBCT imaging. Terminology and technical device properties and settings were not consistent in the literature. An attempt was made to provide a minimal set of CBCT device-related parameters for dedicated OMF scanners as a guideline for future studies.

A comparison of cephalometric analysis using radiographs and craniofacial computed tomography in patients with obstructive sleep apnea syndrome: preliminary report.

The aim of this study was to describe the similarities and differences as well as the convenience in using of cephalometric radiographs and craniofacial computed tomography in obstructive sleep apnea syndrome (OSAS) patients and to demonstrate the relationship between the severity of sleep-disordered breathing and severity of cephalometric abnormalities. A total of 28 randomly selected patients with snoring, and varying degrees of sleep-disordered breathing were included in this study. A control group included 22 patients. These patients had no snoring or clinical evidence of sleep-disordered breathing as evaluated by polysomnographic test. No patients had prior pharyngeal or maxillomandibular surgery. All patients were evaluated by otolaryngological examination and had polysomnography, cephalometric radiographs and craniofacial CT scans. In study group the evaluation between cephalometric analysis on radiographs and CT scans was made. The comparison between the control and the study group was also assessed as far as cephalometric data are concerned. The cephalometric parameters revealed major differences between controls and patients with OSAS regarding the size and position of soft palate and uvula, volume and position of tongue, hyoid position, mandibulo-maxillary protrusion and size of the pharyngeal airway space. OSAS is associated with statistically significant changes in cephalometric measurements. Lateral cephalometric analysis and craniofacial CT scans add further information to the anatomical assessment of patients with OSAS. We found craniofacial CT scan measurements to be easier and more accurate especially when applying to soft tissues. We believe that this method may also be useful for patient classification to surgical procedures.

Three-dimensional reconstruction of the odontophoral cartilages of Caenogastropoda (Mollusca: Gastropoda) using micro-CT: Morphology and phylogenetic significance.

Odontophoral cartilages are located in the molluscan buccal mass and support the movement of the radula during feeding. The structural diversity of odontophoral cartilages is currently known only from limited taxa, but this information is important for interpreting phylogeny and for understanding the biomechanical operation of the buccal mass. Caenogastropods exhibit a wide variety of feeding strategies, but there is little comparative information on cartilage morphology within this group. The morphology of caenogastropod odontophoral cartilages is currently known only from dissection and histology, although preliminary results suggest that they may be structurally diverse. A comparative morphological survey of 18 caenogastropods and three noncaenogastropods has been conducted, sampling most major caenogastropod superfamilies. Three-dimensional models of the odontophoral cartilages were generated using X-ray microscopy (micro-CT) and reconstruction by image segmentation. Considerable morphological diversity of the odontophoral cartilages was found within Caenogastropoda, including the presence of thin cartilaginous appendages, asymmetrically overlapping cartilages, and reflexed cartilage margins. Many basal caenogastropod taxa possess previously unidentified cartilaginous support structures below the radula (subradular cartilages), which may be homologous to the dorsal cartilages of other gastropods. As subradular cartilages were absent in carnivorous caenogastropods, adaptation to trophic specialization is likely. However, incongruence with specific feeding strategies or body size suggests that the morphology of odontophoral cartilages is constrained by phylogeny, representing a new source of morphological characters to improve the phylogenetic resolution of this group.

Four-dimensional analysis of stomatognathic function.

Many researchers have attempted to clarify the complex relationships between stomatognathic function and craniofacial morphology. Most studies investigated the trajectories of incisal or condylar points and measured temporomandibular morphology projected onto 2-dimensional radiographic films. Although these methods provided valuable information, their diagnostic capabilities were limited. We introduce a new 4-dimensional (4D) analysis of stomatognathic function that combines the 3-dimensional (3D) computed tomography of the cranium and mandible, dental surface imaging with a noncontact 3D laser scanner, and mandibular movement data recorded with a 6 degrees of freedom jaw-movement analyzer. This method performs dynamic and precise simulations that can analyze and display condyle to fossa distances and occlusal contacts during mandibular function. These comprehensive relationships can be analyzed and displayed not only at intercuspal position, but also at any mandibular position during functional movements. We believe that our 4D analyzing system will be useful for diagnosing temporomandibular disorders of patients with jaw deformities and other malocclusions.

Three-dimensional CT examination of the mastication system in the giant anteater.

The gross anatomy of the mastication system of the giant anteater (Myrmecophaga tridactyla) was examined by means of three-dimensional image analysis. The anteater rotates the mandibles medially and laterally to control its tongue when it is elongated and to house it when it is relaxed. Three-dimensional CT image analysis demonstrated that the shape and size of the oral cavity changes drastically when the mandibles are rotated. The oral cavity expands bilaterally when the dorsal part of the mandibles bend medially. Macroscopic observations and muscle-weight data supported the observation that the superficial temporal and medial pterygoid muscles act as the main medial and lateral rotators of the mandible, respectively. The low height of the mandibular ramus and the incomplete zygomatic arch in this species represent adaptations for the rotational movement of the mandibles, since they both contribute to the medially oriented transmission of force from the temporal muscles and to preventing collision between the mandibles and the cranium during the rotational movement.

[Functional investigation of the stomatognathic system attached to an ultrasound computer module]. / A stomatognath rendszer ultrahangos--számítógépes modullal kiegészitett--funkcionális vizsgálata.

The ARCUS digma "3D ultrasound navigator" is such an up-to-date diagnostic instrument which allows us to analyze the kinematics of the mandible. The equipment gives insight into the condylar and incisal points, the synchronous spatial movement of the right and left condylar points and the kinematic axis, its change of speed that can all refer to discoordination, limitation of movement, hypermobility leading to functional disorders. After taking medical and dental history, clinical examination and X-ray diagnosis we examined people (new patients) suffering from TMJ dysfunction with the ARCUS digma, too. We present some typical functional mandibular movements. We can not only rely on subjective judgements but it also provides an objective diagnosis based on numerical data. It does not replace but rather complies with the conventional methods and puts the diagnostic and therapeutical procedures known so far into a new dimension. The results demonstrate that this sort of investigation will not put an end to the necessity of traditional procedures used up till now but complete them, and at the same time it provides diagnostic surplus and it is indispensable for patients suffering from dysfunctional disorders to be treated in a modern way.

Repercusiones clínico radiográficas de la artritis reumatoidea sobre la articulación temporomandibular / Clinic and radiographic repercussions of rheumatoid arthritis on the temporomandibular joint

La articulación temporomandibular es susceptible a una variedad de cambios artríticos, incluyendo osteoartritis (OA), artritis psoriásica (AP) y artritis reumatoidea (AR). Los síntomas más frecuentes que corresponden a las ATM son dolor durante el movimiento, sensibilidad a la palpación, rigidez, crepitación y tumefección. Los objetivos terapéuticos del tratamiento incluyen mantenimiento de la función aliviando los síntomas de dolor, rigidez e hinchazón. El uso de drogas antinflamatorias no esteroideas es usualmente el primer nivel de tratamiento farmacológico. Otro tipo de drogas también son utilizadas. Las modificadoras de la enfermedad alteran el curso de ésta. Estos agentes parecen limitar el daño a las articulaciones. En el presente trabajo se trató de establecer a través de indicadores clínicos y radiográficos la correlación entre el tiempo de evolución, el estado de la enfermedad sistémica y el compromiso de la ATM (AU)