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.

Description of tongue movements on swallowing patterns.

OBJECTIVE: The purpose of this study was to compare the different swallowing patterns regarding tongue movement during saliva swallowing in healthy participants. DESIGN: Seventeen participants (23.0 ± 3.6 years old) were included in this cross-sectional study. The movement of the tongue (anterior, middle and posterior portions) on the three axes of space (inferior-superior, anterior-posterior and medial-lateral) was recorded using a 3D electromagnetic articulograph. The tongue movement patterns registered during saliva swallowing were classified according to Bourdiol et al. (2014) into Type I, II or III. RESULTS: Three swallowing patterns were identified (Type I, 64.7 %; Type II, 5.9 %; and Type III, 29.4 %). On the anterior-posterior axis, the displacement of the three portions of the tongue was significantly higher in Type III pattern compared with the Type I pattern. Furthermore, on the superior-inferior axis, the displacement of the anterior portion was significantly higher in Type III pattern compared with Type I pattern. In Type I pattern, on the inferior-superior axis, the smallest range of displacement occurred in the anterior portion of the tongue, followed by the middle and, finally, the posterior portion. In the analysis of Type III swallowing pattern, no significant differences were found on the range of displacement of the tongue portions on the three axes. CONCLUSION: Statistical differences were found between swallowing patterns Type I and III regarding tongue movement. The frequency of pattern II found in the participants of this study was not high enough to compare the three patterns. However, the results obtained indicate that the methodology applied could be used to identify the patterns based on quantitative data.