Alterations in the masticatory system in patients with amyotrophic lateral sclerosis and its management with an oral appliance

Abstract

INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by progressive degeneration of the lower (LMN) and upper motor neurons (UMN) in the spinal cord and brain, causing muscle atrophy, muscle weakness, and spasticity. AIMS: With the present thesis we aimed to investigate the alterations and functional limitations of the masticatory system in patients with ALS. The thesis comprises three articles. METHODS: The first two studies assessed a total of 153 ALS patients and 23 control subjects. In study I, the Diagnostic Criteria for Temporomandibular Disorders protocol (DC/TMD) and a specific questionnaire to assess aspects of masticatory dysfunction and frequency of self-injury of the oral mucosa were applied to all participants. Maximum bite force and maximum finger-thumb grip force were determined. In study II, all participants answered using the 8- item Jaw Functional Limitation Scale (JFLS-8). Patients with ALS were grouped by neurologic examination as follows: non- bulbar ALS, bulbar UMN-predominant ALS; bulbar LMN-predominant ALS; and bulbar balanced (UMN + LMN) ALS. Study III included eleven patients with ALS who sought oral treatment because of oral self-biting or TMD-related symptoms. A custom complete-coverage acrylic resin device was fabricated and fitted to each participant. A follow-up visit was planned for 3 months after the placement of the oral appliance, at which point the patients would rate the degree of improvement or worsening of the chief complaint and their degree of satisfaction with the treatment. RESULTS: Study I showed that maximum unassisted and assisted mouth opening, protrusion, left laterotrusion, and finger-thumb grip force were significantly reduced in both spinal- and bulbar-onset patients compared to the control group; however, bite force was reduced only in bulbar-onset patients. ALS patients with tube feeding had the greatest reduction in maximum bite force and mandibular opening. There was no relationship between TMD and ALS. Oral self-injury due to biting was more frequent in the ALS group than in the control group and in the bulbar-onset group compared to the spinal- and respiratory-onset groups. Of the ALS patients in the study, 10% sought dental treatment related to the condition. Thus, in study II, patients with non-bulbar ALS had similar mandibular limitations to healthy participants. Only patients with balanced UMN and LMN bulbar manifestations reported greater difficulties in chewing soft food or in jaw mobility compared to the non-bulbar ALS group. Patients with bulbar involvement also had greater difficulties in chewing tough food or chicken and in swallowing and talking compared to the non-bulbar group, regardless of whether UMN or LMN predominant. Participants in study III reported a mean of 61% improvement of the chief complaint and a mean of 84% satisfaction with the treatment. The mean rate of compliance was 62% of the recommended time and only a few adverse effects were reported. CONCLUSIONS: Patients with ALS showed a reduction in finger-thumb grip force that was twice as great as the reduction in bite force. The maximum range of mandibular movement was also reduced, especially in bulbar-onset patients. ALS patients did not have a higher prevalence of TMD, but did have more traumatic mucosal injury than controls. Bulbar involvement in patients with ALS is associated with functional limitation of the masticatory system. However, balanced bulbar UMN and LMN involvement is associated with the worst impairments, affecting soft food chewing and opening the jaw widely. Patients with ALS were highly satisfied with the use of an oral appliance to manage oral self-biting or TMD-related symptoms. Adherence to this treatment was high and no major adverse effects were observed. The dentist should be an integral part of the multidisciplinary team to manage ALS patients.

INTRODUCCIÓN: La esclerosis lateral amiotrófica (ELA) es una enfermedad neurodegenerativa caracterizada por la degeneración progresiva de las neuronas motoras inferiores (MNI) y superiores (MNS). OBJETIVOS: El objetivo principal de esta tesis ha sido investigar las alteraciones y limitaciones funcionales del sistema masticatorio en pacientes con ELA. La tesis se ha basado en la integración de tres artículos. MATERIAL Y MÉTODOS: Los dos primeros estudios evaluaron 153 pacientes con ELA y 23 sujetos control. En el primer estudio se aplicó el protocolo de criterios diagnósticos para trastornos temporomandibulares (DC/TMD) y un cuestionario para evaluar aspectos de la disfunción masticatoria y la frecuencia de lesiones orales traumáticas por mordisqueo involuntario. Se determinó la fuerza de mordida y la fuerza muscular entre los dedos pulgar e índice. En el segundo estudio se utilizó la escala de limitación funcional de la mandíbula (JFLS-8). El tercer estudio incluyó a once pacientes con ELA a los que se les colocó un dispositivo intraoral y se valoró el grado de satisfacción y la mejoría en su calidad de vida con el tratamiento. RESULTADOS: En el primer estudio los pacientes con ELA presentaron una reducción en los movimientos mandibulares, en la fuerza de mordida y en la fuerza muscular entre los dedos pulgar e índice. En el segundo estudio, los pacientes con ELA bulbar informaron mayores dificultades para masticar y movilidad mandibular reducida en comparación con el grupo de ELA sin afectación bulbar. Los participantes del tercer estudio informaron una media de un 61% de mejoría con respecto al motivo de consulta y una media del 84% de satisfacción con el dispositivo intraoral. CONCLUSIONES: Los pacientes con ELA presentaron una reducción en la fuerza muscular entre los dedos pulgar e índice y en la fuerza de mordida, un rango de movimiento mandibular reducido y mayor frecuencia de lesiones orales traumáticas por mordisqueo involuntario. La afectación bulbar en estos pacientes está asociada a una limitación funcional del sistema masticatorio. La satisfacción de los pacientes con ELA con un dispositivo oral para controlar las lesiones orales traumáticas por mordisqueo involuntario o los síntomas relacionados con TMD fue alta.