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Item Type: Tesi di dottorato
Resource language: English
Date: 10 December 2018
Number of Pages: 71
Institution: Università degli Studi di Napoli Federico II
Department: Neuroscienze e Scienze Riproduttive ed Odontostomatologiche
Dottorato: Medicina clinica e sperimentale
Ciclo di dottorato: 31
Coordinatore del Corso di dottorato:
Michelotti, AmbrosinaUNSPECIFIED
Date: 10 December 2018
Number of Pages: 71
Keywords: masticatory muscles, electromyography, temporomandibular disorders, juvenile idiopathic arthritis, pressure pain threshold
Settori scientifico-disciplinari del MIUR: Area 06 - Scienze mediche > MED/28 - Malattie odontostomatologiche
Date Deposited: 19 Dec 2018 15:17
Last Modified: 26 Jun 2020 20:23

Collection description

The assessment of masticatory muscles function can be better realized by using additional diagnostic devices such as electronic devices. The evaluation of masticatory muscles activation in terms of asymmetry and/or bite force could be useful in growing patients because of the possible onset of skeletal asymmetries and TMD related to a pathological condition affecting temporomandibular joint or to a malocclusion. The activity of muscles is commonly investigated by using surface electromyography (sEMG) in order to identify possible muscular impairment. Masticatory muscles evaluation can include measurements of muscle tenderness, pain detection thresholds, pain tolerance thresholds, pain response to suprathreshold stimuli and temporal summation. The study of pain perception could be the key in understanding that sensitization of central nociceptive pathways is a relevant mechanism involved in the physiopathology of muscular pain. Pain perception can be assessed by pain pressure threshold (PPT) measurement. PPT has been shown to be a valid method to measure mechanical pain threshold in human muscles, including craniofacial ones. The aim of this work is to evaluate the masticatory muscles function in patients affected by different pathological conditions, which are TMDs, Juvenile Idiopathic Arthritis (JIA) and Unilateral Posterior Cross Bite (UPCB). The activity of Anterior Temporalis (AT) and Masseter (MM) muscles was analyzed by using a standardized EMG protocol in different samples, which were adult patients affected by Myalgia pain, children affected by JIA and children affected by UPBC malocclusion compared to control groups. In patients affected by JIA also the PPT of AT and MM muscles and Temporomandibular Joint (TMJ) was evaluated by using a digital algometer. Results reported a similar asymmetric contraction pattern between Myalgia patients and healthy subjects with a higher MM muscles activity compared to AT muscle one in Myalgia patients. However, for the index evaluating the muscular work it was found a significant difference with a higher value reported by Myalgia patients compared to healthy subjects. Analyzing UPBC patients, results showed no significant difference between children affected by this malocclusion and control group for all EMG indices. Moreover, no differences were found also comparing UPCB patients at baseline with the same sample after the malocclusion correction. Also for JIA no differences were found between patients and healthy subjects were EMG indices were analyzed. Only comparing the AT and MM muscles activity it was found a difference between groups with a higher MM muscles activity reported by JIA patients. Moreover, for JIA patients a significant difference was found for PPT values of masticatory muscles and TMJ sites compared to healthy subjects with lower values reported by JIA patients. In conclusion, Myalgia TMD patients reported a greater muscular work. There was no association between asymmetric muscular activity and Myalgia pain. Children with and without UPCB present slight asymmetric activity of AT and MM muscles during functional tasks and these muscles of children with UPCB are not more asymmetric than healthy children without crossbite. Furthermore, the treatment of UPCB with RME does not reduce the asymmetry of MM and AT activity. Children with and without JIA present slight asymmetric activity of AT and MM, with major activity of MM muscles reported by JIA patients, during functional tasks. These muscles in JIA patients are not more asymmetric than healthy children without JIA. Referring to PPT evaluation, lower PPT values were found in the orofacial areas in JIA patients compared to healthy subjects regardless of TMJ involvement; we could assume that it is the pathology itself to produce a central hypersensitivity cause of a reduced pain tolerance. Diagnostic instruments could improve the quantitative and qualitative assessment of masticatory muscles. The evaluation of the EMG activity and the measurement of PPT of masticatory muscles could be identified as some of these diagnostic tools. For the EMG assessment, from this works we can conclude that the asymmetry is an intrinsic characteristic of each subjects. PPT evaluation of masticatory muscles could be used to better understand the pain perception in patients affected by systemic disease.


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