Alterations in the stomatognathic system due to amyotrophic lateral sclerosis

Abstract Objectives: To compare the molar bite force, electromyographic activity, chewing efficiency and thickness of the masseter and temporalis muscles in individuals with amyotrophic lateral sclerosis (ALS) and healthy individuals. Material and Methods: Thirty individuals enrolled in the study were divided into the study group (with ALS, n=15) and control group (healthy individuals, n=15). Data regarding molar bite force (right and left), electromyographic activity (mandibular rest, right and left laterality, protrusion, and maximum voluntary contraction), chewing efficiency (habitual and non-habitual), and masticatory muscle thickness (rest and maximum voluntary contraction) were tabulated and subjected to statistical analysis (Student's t-test, p≤0.05). Results: Comparisons between the groups demonstrated a statistically significant increase in the electromyographic activity of the right masseter (p=0.03) and left masseter (p=0.03) muscles during mandibular rest; left masseter (p=0.00), right temporalis (p=0.00), and left temporalis (p=0.03) muscles during protrusion; and right masseter (p=0.00), left masseter (p=0.00), and left temporalis (p=0.00) muscles during left laterality, in individuals with ALS as compared with healthy individuals. A statistically significant decrease was observed in the habitual chewing efficiency of the right masseter (p=0.00) and right temporalis (p=0.04) muscles in individuals with ALS. No statistically significant difference between the groups was found the masticatory muscle thickness and maximal molar bite force. Conclusions: ALS may lead to modifications in the activities of the stomatognathic system, including muscular hyperactivity and reduction in chewing efficiency; however, no change has been observed in the masticatory muscle thickness and molar bite force.

Mejoramiento electromiográfico de los maseteros y temporales, en pacientes con Clase III tratados neuromuscularmente con TENS / Electromyographic improvement of masseters and temporal, in patients with Class III treated neuromuscularly with TENS

Las Clases III están caracterizadas por una pérdida de dimensión vertical, asociada a un acortamiento de las inserciones y desbalance musculares. Este estudio fue diseñado para determinar los cambios en la amplitud de la electromiografía (EMG) de la actividad muscular de los maseteros (M) y temporales (T) en reposo y en apretamiento en pacientes con Clase III, tratados neurofisiológicamente con electroestimulación nerviosa transcutánea (Transcutaneous Electrical Nerve Stimulation - TENS), utilizando un dispositivo intraoral (DIO) las 24 horas durante 30 días. Doce pacientes con Clase III molar (edad promedio: 27,7+-1,2 años) formaron parte del grupo tratado con TENS y DIO, y 10 pacientes con edades similares de Clase III, sin tratamiento, conformaron el grupo control. La EMG muscular de M y T fue estudiada antes y después del tratamiento. Los datos fueron analizados utilizando la prueba "t" de Student; adicionalmente, se calculó la media y el desvío estándar de la actividad de cada músculo. Los pacientes tratados con TENS y DIO presentaron una disminución marcada de la hiperactividad en reposo de los M y T (p=0,0001 - asociación altamente significativa - A/S) y un aumento de la misma en apretamiento (p=0,0001 A/S). El grupo control mantuvo similar actividad en reposo y en la EMG en apretamiento, mostrando asociaciones no significativas. Estos resultados confirman que utilizar el TENS y el DIO en pacientes mejora la actividad de los músculos M y T , disminuyendo la hiperactividad en reposo y mejorando la misma en apretamiento. De este modo cambiaría sustancialmente la posición inicial de la oclusión para tratar las maloclusiones de Clase III, lo cual facilita el diagnóstico, pronóstico y plan de tratamiento.

Classes III are characterized by a loss of vertical dimension associated with a shortening of the muscle attachments and imbalance. This study was designed to stablish the changes in the amplitude of the electromyogram (EMG) of temporal (T) and masseter (M) muscle activity at rest and during clenching in patients with Class III, neurophysiologically treated with Transcutaneous Electrical Nerve Stimulation (TENS), using an intraoral device (DIO) 24 hours for 30 days. Twelve patients with Class molar relation (mean age, 27.7+-1.2 years) were part of the group treated with TENS and DIO and 10 untreated patients with similar ages and Class III, formed the control group. The muscle EMG of M and T was studied before and after treatment. Data were analyzed using the Student´s test, additionally, mean and standard deviation of the activity of each muscle was calculated. Patients treated with TENS and DIO showed a marked decrease in hyperactivity of M and T at rest (p=0.0001 A/S) and an increase of it during clenching (p=0.0001 A/S). The control group kept similar activity at rest and in the EMG during clenching, showing no significant associations. These results confirm that using TENS and DIO in patients improves muscle activity of T and M as decreasing hyperactivity at rest and improving it during clenching. Thus, the initial position of the occlusion to treat Class III malocclusions should substantially change, thereby providing diagnosis, prognosis and treatment plan.

Cysticercosis of the masseter.

Cysticercosis of the oral cavity is a very rare soft tissue lesion and very few cases have been reported worldwide. Here we report a case of a cysticercous cellulosae within the masseter muscle which was diagnosed with the help of high resolution ultrasonography (USG) and ultrasound guided fine needle aspiration cytology (FNAC) and managed conservatively using oral antiparasitic medication. Cysticercosis is not commonly considered in the diagnosis of swellings of the head and neck and this is the reason why they are of utmost interest to the practitioner and have to be studied.

Cysticercosis of masseter.

Cysticercosis is a parasitic infestation caused by the larval stage of Taenia solium, a cestodic paratise. It is a common disease in developing countries where it is also endemic. The most commonly infested body organs include subcutaneous tissues, brain and skeletal muscles. It is interesting to note that oral lesion of cysticercosis is a rare event. Here we report an isolated lesion of cysticercosis in the masseter muscle.

Masseter muscle thickness in different skeletal morphology: An ultrasonographic study.

Background: The thickness of the masseter muscle during relaxation and contraction states was measured by ultrasonography. Subjects were classified according to their sagittal skeletal relationships. The association between muscle thickness and facial morphology was studied. Context: Masseter muscle thickness influences the skeletal patterns. Aim: To measure and compare the thickness of the masseter muscle in individuals with skeletal class I occlusion and skeletal class II malocclusions and to correlate its relationship with craniofacial morphology. Settings and Design: The study was conducted in a hospital setup and was designed to study the thickness of the masseter muscle in different skeletal morphologies. Materials and Methods: Seventy two individuals between the ages of 18 and 25 years were divided into Group I, Group IIA and Group IIB according to their skeletal relationships. Masseter muscle thickness was measured by ultrasonography. Eight linear and six angular cephalometric measurements were assessed. Statistical Analysis Used: Analysis of variance and Pearson's correlation analysis. Results: There was a statistically significant difference in muscle thickness between subjects of different skeletal patterns. Significant positive correlation between masseter muscle thickness and posterior total face height, jarabak ratio, ramus height, mandibular length and significant negative correlations with mandibular plane angle, gonial angle and PP-MP angle were observed. Conclusion: This study indicates the strong association between the masseter muscle and skeletal morphology.