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Swallowing changes related to chronic temporomandibular disorders
Carlos Eduardo Fassicollo
&Bárbara Cristina Zanandréa Machado
&Denny Marcos Garcia
Cláudia Maria de Felício
Received: 31 May 2018 /Accepted: 22 November 2018 /Published online: 28 November 2018
#Springer-Verlag GmbH Germany, part of Springer Nature 2018
Objectives To investigate whether chronic temporomandibular disorder (TMD) patients showed any changes in swallowing
compared to a control group. Moreover, it was examined whether swallowing variables and a valid clinic measure of orofacial
myofunctional status were associated.
Material and methods Twenty-three patients with chronic TMD, diagnosed with disc displacement with reduction (DDR) and
pain, according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD), and 27 healthy volunteers (control
group) were compared. Surface electromyography (EMG) of the temporalis, masseter, sternocleidomastoid, and suprahyoid
muscles was performed during swallowing tasks of thin liquid (10 and 15 mL) and spontaneous saliva. Data were normalized.
Results Compared to the control group, TMD patients showed a prolonged duration of swallowing for liquid and saliva and
required a longer time to reach the activity peak and half the integral. While the overall mean value of the relative peaks was
similar for the groups, the suprahyoid peak was significantly lower in the TMD group during swallowing of liquid. Moreover,
TMD patients recruited the jaw elevator muscles proportionally more than controls. The orofacial myofunctional status was
moderately correlated with EMG parameters.
Conclusion Patients with chronic TMD showed temporal prolongation and changes in the relative activity of the muscles during
the swallowing tasks.
Clinical relevance The present results contribute additional evidence regarding the reorganization of muscle activity in patients
with chronic TMD.
Keywords Temporomandibular disorders .Deglutition .Swallowing .Electromyography .Jaw muscles .Suprahyoid muscles
The term temporomandibular disorder (TMD) defines a group
of musculoskeletal conditions that involve the temporoman-
dibular joints (TMJ), the masticatory muscles, and related
structures. Orofacial pains and a sensation of limitation of
mandibular functions are the dominant characteristics of
TMD [1,2]. Changes in behavior and in the masticatory phys-
iology have been reported in various studies [2–6]. Patients
with TMD also report swallowing difficulties [2,7], but little
is known about the electrophysiology of swallowing in this
Swallowing is an essential orofacial function for the nutri-
tion and hydration of the organism. Its role is to guide excess
saliva or the food bolus from the oral cavity to the stomach,
while simultaneously protecting the airways. The motor con-
trol of the various muscles of the orofacial region and cervical
and respiratory muscles for efficient and safe swallowing is
started and guided by the central nervous system based on the
sensory information of the orofacial region. The oral phase of
swallowing can be controlled voluntarily, whereas the pharyn-
geal and esophageal phases are involuntary [8–10].
When swallowing, persons with proper occlusion and with
no disorders of the masticatory systemocclude their teeth .
The tongue then raises its tip in the direction of the alveolar
ridge and gradually expands the area of contact with the palate
from the anterior to the posterior region, compressing the bo-
lus into the pharynx . In contrast, according to studies
*Cláudia Maria de Felício
Department of Ophthalmology, Otorhinolaryngology and Head and
Neck Surgery School of Medicine of Ribeirão Preto, University of
São Paulo –USP, Avenida Bandeirantes, 3900, Ribeirão
Preto, SP 14049-900, Brazil
Craniofacial Research Support Center, University of São Paulo –
USP, Ribeirão Preto, SP, Brazil
Clinical Oral Investigations (2019) 23:3287–3296