Determination of Micromovements in Removable Prosthesis during Mastication: A Pilot Study with 3D Electromagnetic Articulography.

Edentulism can generate negative impacts on self-esteem, interpersonal relationships, and oral functions. Removable prostheses are commonly used for tooth replacement, but they may cause discomfort due to micromovements during mastication. Objective and quantifiable methods are needed to evaluate these micromovements. A pilot study was conducted to determine the micromovements in removable prostheses during mastication using a 3D electromagnetic articulography (EMA-3D) system. One elderly participant wearing lower removable prostheses and an upper total well-fitting removable prosthesis was studied. The EMA-3D system was used to record movements in three spatial planes. Peanuts were given as test food, and the participant was instructed to chew normally while recordings were carried out until feeling the need to swallow. Analyses of the upper total prosthesis show micromovements ranging from 0.63 ± 0.11 to 1.02 ± 0.13 mm. During simultaneous analyses of the upper prosthesis and lower partial prosthesis, interference was not observed. This pilot study demonstrated the feasibility of using the EMA-3D system to evaluate micromovements in removable prostheses during mastication. Further research is needed to evaluate a larger sample and assess the clinical implications of these micromovements.

Chewing Analysis by Means of Electromagnetic Articulography: Current Developments and New Possibilities.

Chewing is a complex procedure that involves sensory feedback and motor impulses controlled by the trigeminal system in the brainstem. The analysis of mandibular movement is a first approximation to understanding these mechanisms. Several recording methods have been tested to achieve this. Video, ultrasound, the use of external markers and kinesiographs are examples of recording systems used in research. Electromagnetic articulography is an alternative method to those previously mentioned. It consists of the use of electromagnetic fields and receiver coils. The receiver coils are placed on the points of interest and the 3D coordinates of movement are saved in binary files. In the Oral Physiology Laboratory of the Dental Sciences Research Center (Centro de Investigación en Ciencias Odontológicas-CICO), in the Faculty of Dentistry at the Universidad de La Frontera (Temuco, Chile) several research studies have been carried out using the AG501 3D EMA articulograph (Carstens Medizinelektronik, Lenglern, Germany). With this device, they developed a series of protocols to record mandibular movement and obtain new information, such as the 3D Posselt polygon, the area of each polygon, individualized masticatory cycles and speed and acceleration profiles. Other investigations have analyzed these parameters, but separately. The AG501 allows for holistic analysis of all these data without altering natural movement. A limitation of this technology is the interference generated by its metallic elements. The aim of the present work is to show the developed methods used to record mandibular movement in the CICO, using the AG501 and compare them with others used in several research studies.

Characterization of Mandibular Border Movements and Mastication in Each Skeletal Class Using 3D Electromagnetic Articulography: A Preliminary Study.

Mandibular movement recording is relevant for the planning and evaluation of mandibular function. These movements can include mandibular border movements (MBM) or mastication. Our objective was to characterize the kinematics of MBM and mastication among skeletal classes I, II, and III in the three spatial planes. A descriptive cross-sectional study was conducted with 30 participants. Instructions were provided on how to form Posselt's envelope and to perform masticatory. After data processing, we obtained numerical values for the areas, trajectories, and ranges of MBM that formed Posselt's envelope and the values for speed, masticatory frequency, and the areas of each masticatory cycle. Significant differences were found in the area of Posselt's envelope in the horizontal plane between skeletal classes I and III and in the range of right laterality between skeletal classes II and III. Mastication showed significant differences in the area of the masticatory cycles in the horizontal plane between classes I and III and between classes II and III. In conclusion, there were differences in MBM and mastication between skeletal classes III and I in the horizontal plane. This study supports the need to establish normal values for mandibular kinematics in skeletal class III.

Determination of Mandibular Position and Mouth Opening in Healthy Patients and Patients with Articular and/or Muscular Pathology: A Pilot Study with 3D Electromagnetic Articulography and Surface Electromyography.

Temporomandibular disorders (TMDs) are a group of pathologies that affect the temporomandibular joint and its related structures, producing intracapsular and muscular pathologies. The aim of this study is to describe, by electromagnetic articulography (EMA) and simultaneous electromyography (sEMG), the mandibular postural position and mouth opening in healthy patients and with articular and/or muscular pathology. MATERIALS AND METHODS: A pilot study was conducted with a sample of sixteen participants aged 18 years or older who attended the TMDs and Orofacial Pain Polyclinic of the University of La Frontera due to TMDs. The physiological inoculation space was evaluated from the mandibular postural position (MPP) with swallowing command and without command, in both healthy patients and patients with articular, muscular, and mixed TMDs, measured simultaneously with EMA and sEMG. An angular measurement of the oral opening was also performed with the data obtained. RESULTS: The physiological inoculation space was obtained from the determination of the MPP through the procedures with swallowing command and without command, and different mouth opening degrees were evaluated. CONCLUSIONS: Simultaneous position and sEMG records can be produced from EMA, and different characterization variables such as the vertical distance, Euclidean distance, and angle can be obtained.

Actualización del análisis de los movimientos mandibulares a través de articulografía electromagnética / Updating the analysis of mandibular movements through electromagnetic articulography

El objetivo de registrar los movimientos mandibulares es obtener parámetros relevantes que permitan evaluar el estado de la articulación temporomandibular (ATM) y de los músculos involucrados en la masticación. El movimiento mandibular se debe a un conjunto complejo de rotaciones y traslaciones tridimensionales realizadas por la ATM, limitado por los ligamentos y las superficies articulares de estas, y por la morfología y la alineación de los dientes, cuando la mandíbula se desplaza sobre estos límites, se llaman movimientos bordeantes mandibulares. El objetivo de este artículo es realizar una descripción actualizada de los movimientos mandibulares a través de articulografía electromagnética. Los movimientos mandibulares bordeantes se clasifican según el plano del espacio en que se muevan, de esta manera tenemos movimientos bordeantes en el plano sagital, en el plano horizontal y el plano frontal, y en cada plano dibujan un polígono distinto, llamados polígonos de Posselt. Estos polígonos pueden ser registrados mediante Articulografía electromagnética, gracias a esta tecnología también se pueden extraer algunos parámetros interesantes, como por ejemplo: la trayectoria total recorrida por la mandíbula al describir cada polígono, rangos de desplazamiento en cada plano, área total de cada polígono de Posselt. La apertura mandibular se mide como la distancia entre los márgenes incisales de los incisivos centrales superiores e inferiores en apertura máxima más la sobremordida. El análisis de esta es una parte importante del examen clínico en odontología, ya que una apertura limitada puede ser resultado de trastornos en la articulación temporomandibular, fibrosis oral submucosa, enfermedad reumática o trauma facial. Las mediciones tridimensionales que se obtienen gracias a la Articulografía electromagnética, son apropiados para determinar los rangos normales de apertura, su exactitud permite la realización de investigaciones en el área, abriendo un amplio campo en el análisis de los movimientos mandibulares.

SUMMARY: The objective of recording mandibular movements is to obtain relevant parameters that allow the evaluation of the state of the temporomandibular joint (TMJ) and of the muscles involved in mastication. Mandibular movement is due to a complex set of three-dimensional rotations and translations performed by the TMJ, limited by the ligaments and their articular surfaces, and by the morphology and alignment of the teeth, when the mandible moves over these limits, they are called mandibular border movements. The aim of this article is to provide an updated description of mandibular movements through electromagnetic articulography. Mandibular border movements are classified according to the plane of space in which they move, thus we have border movements in the sagittal plane, in the horizontal plane and the frontal plane, and in each plane they draw a different polygon, called Posselt polygons. These polygons can be recorded by electromagnetic articulography, thanks to this technology some interesting parameters can also be extracted, such as: the total trajectory covered by the mandible when describing each polygon, displacement ranges in each plane, total area of each polygon of Posselt. Mandibular opening is measured as the distance between the incisal edges of the upper and lower central incisors at maximum opening plus the overbite. The analysis of mandibular opening is an important part of the clinical examination in dentistry as a preliminary evaluation, since limited opening can be the result of temporomandibular joint disorders, submucous oral fibrosis, rheumatic disease or facial trauma. The three-dimensional measurements that are obtained thanks to the electromagnetic Articulography, are appropriate to determine the normal ranges of opening, its accuracy allows the realization of investigations in the area, opening a wide field in the analysis of mandibular movements. Analysis of mandibular opening is an important part of the clinical examination in dentistry, since limited opening can be the result of temporomandibular joint disorders, oral submucous fibrosis, rheumatic disease, or facial trauma. Analysis of mandibular opening is an important part of the clinical examination in dentistry, since limited opening can be the result of temporomandibular joint disorders, oral submucous fibrosis, rheumatic disease, or facial trauma. The three-dimensional measurements that are obtained thanks to the electromagnetic Articulography, are appropriate to determine the normal ranges of opening, its accuracy allows the realization of investigations in the area, opening a wide field in the analysis of mandibular movements.

A Novel Technique to Accurately Measure Mouth Opening Using 3D Electromagnetic Articulography.

The mouth opening is an important indication of the functionality of the temporomandibular joint (TMJ). Mouth opening is usually evaluated by asking the patient to open their mouth as wide as possible and measuring the distance between the edges of the frontal incisors with a ruler or caliper. With the advancement of technology, new techniques have been proposed to record mandibular movement. The aim of this work is to present a novel technique based on 3D electromagnetic articulography and data postprocessing to analyze the mouth opening considering distances, trajectories, and angles. A maxilla-mandible phantom was used to simulate the mouth opening movement and fixed position mouth opening. This was recorded using the AG501 3D EMA (Carstens Medizinelektronik GmbH, Bovenden, Germany). The collected data was processed using Matlab (Mathworks, Natick, MA, USA). Fix and mobile mouth opening of 1, 2, 3 and 4 cm were simulated. It was possible to evaluate the mandibular opening through the vertical distance, the Euclidean distance, the trajectory, and the opening angle. All these values were calculated and the results were consistent with expectations. The trajectory was the highest value obtained while the vertical distance was the lowest. The angle increased as the mouth opening increased. This new technique opens up new possibilities in future research since oral opening can be analyzed using multiple variables without the need to use different devices or depending on the researcher's experience. This will make it possible to establish which parameter presents significant differences between groups of patients or between patients who have undergone some treatment.

Dimensión vertical de la cara en adultos con diferentes relaciones oclusales / Vertical dimension of face in adults with different Angle class

RESUMEN: Se ha postulado que la posición postural mandibular (PPM) no presentaría la menor actividad electromiográfica (EMG) de los músculos masetero y temporal, y que esta menor actividad se encontraría en una apertura mayor. El objetivo de este estudio fue analizar la PPM en pacientes con diferentes relaciones oclusales y según tipo de método de posicionamiento, relacionándolo con la actividad EMG de los músculos Masetero y Temporal, además del registro de la actividad EMG en diferentes aperturas orales. Se analizó una muestra de 25 adultos de 18 a 28 años. Estos fueron clasificados según su sexo y clasificación de Angle. Se realizaron simultáneamente registros de EMG de superficie -masetero y porción anterior del temporal- y de EMA -posición de la mandíbula respecto al maxilar obteniendo distancia y ángulo- en diferentes posiciones mandibulares: PPM-considerando método sin comando y de deglución- y apertura gradual hasta alcanzar la máxima apertura. Se realizó un análisis estadístico descriptivo. La menor PPM obtenida fue de 1,0 ± 0,6 mm en mujeres Clase III y utilizando la técnica sin comando; el mayor fue de 2,5 ± 0,2 mm en mujeres Clase II y utilizando la técnica de deglución. La apertura angular presentó menor variabilidad que las distancias lineales. La actividad de los músculos Maseteros derecho e izquierdo presentaron valores similares entre sí, al igual que en los rangos de apertura hasta 30 mm en hombres y mujeres y en las diferentes relaciones oclusales. La actividad de los Temporales para hombres y mujeres y en las diferentes relaciones oclusales mostraron variaciones importantes entre derecha e izquierda y en los diferentes grados de apertura. La técnica presentada permitió el estudio de la dimensión vertical y aperturas orales a través de EMA y EMG.

SUMMARY: It has been postulated that the mandibular postural position (MPP) could not present the lower electromyographic activity (EMG) of the Masseter and Temporal muscles, and that the lower activity could be found in a larger opening. The objective of this study was to analyze the PPM in patients with different occlusal relationships and according to the positioning method, relating it to the EMG activity of the Masseter and Temporal muscles, in addition to recording the EMG activity in different oral openings. A sample of 25 adults aged 18 to 28 years was analyzed. Participants were classified according to their sex and Angle classification. Simultaneous recordings of surface EMG -Masseter and anterior portion of the Temporal- and EMA -position of the Mandible with respect to the Maxilla obtaining distance and angle- were performed in different mandibular positions: PPM-considering the method "without command" and "swallowing"- and gradual opening until the maximum opening is reached. A descriptive statistical analysis was performed. The lowest PPM obtained was 1.0 ± 0.6 mm in Class III women and using the "without command" method; the largest was 2.5 ± 0.2 mm in Class II women and using the "swallowing" method. The angular opening presented less variability than the linear distances. The activity of the right and left masseter muscles presented similar values, as well as in the opening ranges up to 30 mm in men and women and in the different occlusal relationships. The activity of the Temporals for men and women and in the different occlusal relationships showed important variations between right and left and in the different degrees of opening. The presented technique allowed the study of the vertical dimension and oral openings through EMA and EMG.