Evaluation of the masticatory biomechanical function in Down syndrome and its Influence on sleep disorders, body adiposity and salivary parameters

Abstract

Objective To evaluate the phenotypic features of the masticatory biomechanics in atypical subjects with Down syndrome (DS). Its influence was analysed on sleep disorders, body adiposity and its risks, and some physicochemical properties of saliva. Methods Seventy subjects were enrolled to assess masticatory biomechanical function and divided into two groups: DS and control groups. Electrical activities of the masseter and temporal muscles (at rest and in maximum voluntary clench‐MVC), maximum bite force‐MBF and maximum mouth opening‐MMO were investigated. Among the atypical subjects, just 24 participants underwent the anthropometry, the polysomnography II and the saliva testing (salivary flow rate‐SFR, buffer capacity‐BC and salivary cortisol levels, morning/SC‐AM and night/SC‐PM). Results MVC and MBF values showed high statistical significance in the control group (P < .001) than in the DS group of 35. MMO values were slightly increased in the DS group in relation to the control group. Overweight and obesity were found in both genders. Atypical women showed higher risk to develop cardiovascular‐metabolic diseases than in atypical men. OSA severe was 20% for atypical women and 42.8% for atypical men, whereas snoring index was present in all genders. SFR was reduced in 100% of atypical subjects (hyposalivation in 10% women and 28.5% men). Furthermore, 100% BC, 66.6% SC‐AM and 91.6% SC‐PM showed normal patterns. Conclusion Masseter and temporal muscle hypotonia was found in all atypical subjects with DS. This muscle dysfunction strongly was related to overweight/obesity, risks for development of cardiovascular/metabolic diseases, OSA severity, successive snoring episodes and salivary flow reduction in DS.

Electromyographic Study of Masticatory Muscle Function in Children with Down Syndrome

“…An analysis of masticatory muscle function in patients with Down syndrome was also the subject of a study conducted by Gomes et al [4]. The authors assessed the electrical activity of the masseter and temporal muscles at rest and during MVC in adult patients with DS aged between 19 and 40 years.…”

“…Down syndrome (DS) is a chromosomal disease caused by trisomy 21 that is usually accompanied by mental impairment, several comorbidities, and psychosocial limitations [1][2][3]. This genetic abnormality is characterized by variability in cognitive development and individual physical features causing unique health conditions, such as congenital heart disease, craniofacial dysmorphia, muscle hypotonia, gastrointestinal, hands-feet, renal and urogenital deformations, sleep breathing disorders including obstructive sleep apnoea, leukaemia, immune system alterations, premature dementia, Alzheimer's disease, and others [4].…”

“…One of the most common manifestations observed in patients with DS is the generalized muscular hypotonia, especially regarding the masticatory and oropharyngeal muscles, resulting in difficulties when speaking, swallowing, and mastication [1,5]. Patients with DS may experience alterations in the stomatognathic system due to the presence of masticatory muscle dysfunction (as a result of hypotonia) and skeletal developmental abnormalities, e.g., a reduced size of the maxillary and mandibular bones and severely inhibited sagittal development in the midface region, which may result in malocclusion [1,4,6,7]. The most common dental and occlusal disorders in individuals with DS are open bite, crossbite, class III malocclusion, hypodontia, and microdontia [1,8,9].…”

“…The most common dental and occlusal disorders in individuals with DS are open bite, crossbite, class III malocclusion, hypodontia, and microdontia [1,8,9]. Typical oral impairments in subjects with DS include a lack of oral motor coordination (weak jaw-closing muscles, difficulties with jaw stability, weak tongue control, and ineffective lingual lateralisation), problems during eating (poor oral seal, poor sucking, choking, belching, and food leakage from the mouth), uncontrolled facial movements, mouth breathing due to poor muscle tone, and salivary leakage [4][5][6].…”

“…What is important, as sEMG is simple and safe, is that it could be used in studies on children [11,17,18]. To date, information on the electromyographical (EMG) activity of the masticatory muscles in individuals with DS, particularly in the case of very young patients, is limited and the results of the existing studies are not consistent [4,17]. Therefore, further research on masticatory muscle EMG function in children with DS is needed.…”