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Biomechanical behavior of customized splint for the patient with temporomandibular disorders: A three-dimensional finite element analysis

Zhu Yunfan, Zheng Fangjie, Gong Yanji, Yin Deqiang, Liu Yang

Biocybernetics and Biomedical Engineering

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2024

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Vol. 44, no. 1

83--94

EN

The mechanical overloading of temporomandibular joint (TMJ) is generally linked to temporomandibular disorders (TMD). However, in patients with a typical combination of maxillofacial morphology and occlusal features, the reduction of joint load and treatment with general occlusal splints are often ineffective. This study investigates the biomechanical behavior of the stomatognathic system in a TMD patient with personalized splints by finite element analysis. The therapeutic position, determined based on the intercuspal position, served as the basis for designing personalized customized splints. The design of occlusal contact and splint structure was evaluated in terms of their impact on the maximum stress level in the TMJ and the biting forces on the dentition. The relationship between joint stress and biting force was further examined during treatment with different customized splints. In preoperative case, there was a significant increase in stress level and stress concentration in the medial to posterior band of the articular disc. However, in all customized splint cases, the highest stress area shifted to the intermediate zone and exhibited a decrease. Notably, the bi-splints demonstrated superior ability in relieving overloading and balancing the occlusal force on both sides of the dentition, as verified by clinical treatment. The predictable simulated results offer valuable interactive information regarding TMJ overload, aiding doctors in making better-informed clinical decisions in future.

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Influence of the Position of the Mandible on Stresses and Displacements within the Structures of the Temporomandibular Joint

Ryniewicz Anna M., Mazur Konrad, Bojko Łukasz, Ryniewicz Wojciech

Tribologia

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2020

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nr 5

27--38

EN

A model of the temporomandibular joint (TMJ) was developed using the finite element method (FEM). The aim of the procedure is to identify reduced stresses and resultant displacements in the TMJ and to evaluate the transfer of contact loads for the three articulation states of the mandible that represent the activity of the joint. The study mapped the layered structure of the bio-bearing with different strength parameters of the tissues and synovial fluid. The model was loaded with the forces generated by the mandibular abduction muscles during chewing. Our method allowed for the assessment of the transfer of physiological loads within surfaces when lubricating with the synovial fluid and showed compressive stimulation of bone structures. Under load transfer conditions, the maximum values of reduced stresses are located not in the immediate friction zone, but in the structures of the compact and spongy bone.

PL

Opracowano model stawu skroniowo-żuchwowego (SSŻ) z wykorzystaniem metody elementów skończonych (MES). Celem jest identyfikacja naprężeń zredukowanych i przemieszczeń wypadkowych w SSŻ oraz ocena przeniesienia obciążeń kontaktowych dla trzech stanów artykulacyjnych żuchwy, które są reprezentatywne dla czynności tego stawu. W badaniu odwzorowano warstwową budowę biołożyska o zróżnicowanych parametrach wytrzymałościowych tkanek oraz cieczy synowialnej. Model obciążono siłami generowanymi przez mięśnie odwodzące żuchwę w warunkach żucia pokarmów. Zaproponowana metoda pozwoliła na ocenę przeniesienia obciążeń fizjologicznych w stawie skroniowo-żuchwowym. Umożliwiła analizę funkcjonalną krążka stawowego i powierzchni stawowych w warunkach smarowania cieczą synowialną oraz wskazała na stymulację kompresyjną struktur kostnych. W warunkach przenoszenia obciążeń maksymalne wartości naprężeń zredukowanych zlokalizowane są nie w bezpośredniej strefie tarcia, ale w strukturach kości korowej i gąbczastej.

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Biomechanical study on the changes of stress in temporomandibular joints after the orthognathic surgery in patients with mandibular prognathism: a 3D finite element study

Shu Jingheng, Wang Quanyi, Ma Hedi, Teng Haidong, Zheng Tinghui, Liu Zhan

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 2

155--163

EN

Purpose: This study aimed to analyze the changes of the stress distributions in TMJs for the pre- and postoperative patients with mandibular prognathism under unilateral occlusions, a frequent occlusion in mastication. Methods: Pre- and six-mouth postoperative cone-beam computed tomography images of thirteen patients diagnosed with mandibular prognathism were scanned and used to construct complete maxillofacial models, assigned as the Pre and Post group, respectively. Another ten asymptomatic individuals were defined as the Control group. The inhomogeneous properties were assigned to the models. The muscle forces and boundary conditions corresponding to left and right unilateral occlusions were applied on the models. The analysis of variation (ANOVA) was chosen for the comparison among the groups. Results: The results showed that the Pre group had abnormal stress distributions ang higher stress level in TMJs, compared with those of the Post and Control groups. Moreover, from clinical cases, symptoms of temporomandibular disorders (TMDs) always followed with increased stresses. Conclusion: Generally, orthognathic surgeries could improve the stress distribution in TMJs of the patients with mandibular prognathism under the unilateral occlusions. However, the postoperative complications, especially symptoms of TMD, were closely related to changes of stress for patients with mandibular prognathism after orthognathic surgeries. Individual virtual surgery and finite element analysis should be conducted to prevent complications in TMJ.

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Biomechanical comparison between the custom-made mandibular condyle prosthesis and total temporomandibular joint prosthesis in finite element analysis

Xu Xiangloang, Zhang Jiwu, Luo Danmeli, Guo Chuanbin, Rong Qiguo

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 4

151--160

EN

The purpose of this study was to compare the biomechanical behavior of the custom-made mandibular condyle prosthesis and total TMJ prosthesis. Methods: Three models of one beagle dog, the condyle prosthesis (Model 1, replacing the right condyle only), the TMJ prosthesis (model 2, replacing the whole right TMJ) and the intact TMJ (model 3) were established, and the mechanical responses under muscle forces loading were analyzed using finite element method. Results: Models 1 and 3 had the similar stress distribution on the right disc, which suggested that the condyle prosthesis did not change the disc stress so much when the muscle forces were applied. The stress of the right TMJ prosthesis in Model 2 was larger than both Models 1 and 3, and the stress of the contralateral TMJ reduced by 12% in Model 2. The anterior border of the condyle seemed to be a stress concentration region, not only for the intact condyle, but also for the condyle prosthesis and the total TMJ prosthesis. Conclusions: The total TMJ prosthesis changed the biomechanical balance of the bilateral TMJ. When the condyle prosthesis iss applied, the custom-made profile is recommended.

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Uwarunkowania biomechaniczne stawu skroniowo-żuchwowego pod kątem pomiaru przemieszczenia ruchu żuchwy

Jadczak Kamila, Białek Rafał, Wiśnios Michał, Kuchta Marek

Przegląd Elektrotechniczny

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2019

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R. 95, nr 2

88--91

PL

Poniższy artykuł opisuje budowę oraz biomechanikę stawu skroniowo-żuchwowego pod względem pomiarów przemieszczenia żuchwy względem czaszki. Jest to wstęp do opracowania metody pomiaru przemieszczeń żuchwy w ramach projektu POIR.04.01.02-00-0029/17, którego celem jest opracowanie trójwymiarowego modelu stawu skroniowo-żuchwowego w celu odwzorowania działania aparatu kostno-chrzęstnowięzadłowego na potrzeby protetyki, ortodoncji i chirurgii ortognatycznej.

EN

The following article describes the structure and biomechanics of the temporo-mandibular joint in terms of measurements of the mandibular dislocation relative to the skull. This is the introduction to the development of the method of measurement of mandibular movements as part of the project POIR.04.01.02-00-0029 / 17, whose aim is to develop a three-dimensional model of the temporomandibular joint to reproduce the operation of the osteochlear-ligament apparatus for the needs of prosthetics, orthodontics and orthognathic surgery.

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Force ratio in masticatory muscles after total replacement of the temporomandibular joint

Vilimek M., Horak Z., Baca W.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 3

131--136

EN

The temporomandibular (TM) joint is one of the most active joints in the human body, and any defect in this joint has a significant impact on the quality of life. The objective of this study was to analyze changes in the force ratio after TM joint replacement on contralateral TM joint loading. Implantation of an artificial TM joint often requires removal of 3 of the 4 masticatory muscles (activators). In order to perform true loading of the TM joint, loading during mastication was investigated. Input kinematic variables and mastication force were experimentally examined. The inverse dynamics approach and static optimization technique were used for solution of the redundant mechanism. Muscle forces, and reactions in the TM joint were calculated. We modified the model for several different tasks. The m. temporalis and m. masseter were removed individually and together and the forces of mastication on the TM joint were calculated for each variation. To evaluate the results, a parametric numerical FE analysis was created to compare the magnitude of the TM joint loading during the bite process for four different muscle resections. The results show an influence relative to the extent of muscle resection on contralateral TM joint loading in a total TM joint replacement. The biggest increase in the loading magnitude on the contralateral TM joint is most evident after m. masseter and m. temporalis resection. The results from all simulations support our hypothesis that the greater the extent of muscle resection the greater the magnitude of contralateral TM joint overloading.

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Could lower leg Wartenberg test be used as a predictor of restrictions in temporomandibular joint movements in CP patients

Syczewska M., Szczerbik E., Graff K., Olczak-Kowalczyk D., Dąbrowska-Gontarczyk A., Kalinowska M., Jelonek E.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 2

3--7

EN

Purpose: Patients with spasticity suffer not only from neurological problems but also from various dentistry problems due to spasticity of the jaw muscles. Measurements of motion in temporomandibular joints should reflect the amount of abnormal muscle tone of these muscles. The aim of this study was to find out if the measurements of temporomandibular joint movements performed with the ultrasound Zebris device are different in cerebral palsy patients than in healthy subjects; and to find out if the information on the degree of spasticity in the lower legs provided by the Wartenberg test could be used to predict the degree of spasticty in the jaw muscles. Method: Twenty five healthy subjects and 25 cerebral palsy patients participated in the study. Two types of measurements were performed: temporomandibular movements measured with Zebris device, and instrumented Wartenberg test. Results: The laterotrusion and opening movements are different in CP patients than in healthy subjects. Laterotrusion movement correlates with velocity measured during the Wartenberg test. Conclusion: This finding suggests that high spasticity in the lower legs could indicate jaw movement restrictions in CP patients.

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Ocena zaburzeń stawu skroniowo – żuchwowego w aspekcie aktywności bioelektrycznej

Szymańska D.

Aktualne Problemy Biomechaniki

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2014

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z. 8

151--156

PL

Celem pracy była elektromiograficzna ocena i porównanie aktywności bioelektrycznej wybranych mięśni układu stomatognatycznego dwóch osób dotkniętych dysfunkcją stawu skroniowo – żuchwowego (ang. temporomandibular disorders - TMD) o różnym stopniu nasilenia, oraz osoby zdrowej deklarującej brak objawów TMD.

EN

The aim of the study was an electromyography assessment and comparison of stomatognatic system’s selected muscles bioelectrical activity. The material consisted of two subjects who suffers from differential intensity of temporomandibular disorders (TMD) and the another one who’s healthy and doesn’t declare symptoms of TMD

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Ocena cech materiałowych krążków stawowych stawu skroniowo-żuchwowego

Chladek W., Margielewicz J., Czerwik I.

Inżynieria Materiałowa

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2009

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Vol. 30, nr 3

201-206

PL

W pracy przedstawiono wyniki badania właściwości mechanicznych krążków stawowych stawu skroniowo-żuchwowego. Biorąc pod uwagę podobieństwo cech funkcjonalnych ludzkiej i wieprzowej żuchwy, badania zrealizowano na krążkach wieprzowych wyreparowanych bezpośrednio po uboju zwierzęcia (rys. 1, tab. 1). Kierując się rożnymi warunkami pracy poszczególnych fragmentów krążka, jako miejsca istotne wytypowano przednie i tylne struktury obwodowe krążków oraz ich części centralne. Testy prowadzono na uniwersalnej maszynie wytrzymałościowej Zwick przy piłowych charakterystykach zmian siły w zakresie od 0 do 3 N zachodzących z prędkością 1 N/s. Oceniano wpływ kolejnych cykli na kształt pętli histerezy ?(?) oraz zmiany właściwości tłumiących, decydujących w istotny sposób o dystrybucji obciążeń na kość panewki i głowy żuchwy. Na podstawie uzyskanych charakterystyk naprężeniowo-odkształceniowych (rys. 4) określono sztywność oraz efektywny moduł Younga tkanek w strefie pomiaru. Wykazano, że charakterystyki naprężeniowo-odkształceniowe tkanek krążków istotnie zależą od miejsca pomiaru, jak i historii obciążenia. Największe zmiany zachodzą w pierwszych czterech cyklach, a za ustabilizowany cykl można uznać dopiero piąty cykl obciążenia. Wynik ten wskazuje na konieczność weryfikacji wielu danych, wprowadzanych do warunków brzegowych, które zostały uzyskane w próbach statycznych. Niewłaściwym postępowaniem jest również uśrednianie cech materiałowych dla całej objętości krążka. Przy obciążaniu krążków uzyskano zdecydowanie rożne wartości efektywnego modułu Younga dla poszczególnych fragmentów. Wartości te wynosiły dla strefy tylnej 4,44 MPa, środkowej 1,97 MPa oraz przedniej 2,99 MPa (tab. 2) Zarejestrowane przebiegi cykliczne, ujmujące zmiany siły i odkształcenia, były asumptem do sformułowania modelu matematycznego materiału, z jakiego wykonany jest krążek stawu skroniowo-żuchwowego. Największe spadki szerokości pętli histerezy zaobserwowano w strefie przedniej oraz tylnej. W części tylnej dla dziesiątego cyklu pole powierzchni histerezy jest prawie dwukrotnie mniejsze w stosunku do cyklu drugiego, natomiast w strefie przedniej pole powierzchni maleje prawie trzykrotne (tab. 4). W praktyce zjawisko wzrostu sztywności prowadzi do pogorszenia właściwości tłumiących tkanek krążka stawowego. Najsztywniejszy miejscem krążka jest jego część tylna, gdzie sztywność w piątym cyklu obciążenia wy- nosiła 87,1 N/mm. Środek krążka wykazał najmniejszą sztywność, przyjmując wartość 38,7 N/mm (tab. 2). Zgodność modelowego odwzorowania cykli pracy krążka, potwierdziła przeprowadzona weryfikacja, podczas której porównano wyniki symulacji numerycznych z zarejestrowanymi danymi doświadczalnymi. Pozwala to na stwierdzenie, że przyjęty model reologiczny, jak również zidentyfikowane jego parametry dobrze odwzorowują cykle pracy krążka.

EN

The paper presents the results of examination of mechanical properties of the temporomandibular joint discs. Taking into account the similarity of func- tional characteristics of human and pig mandible, the research was taken on pig's discs after animal slaughter (Fig. 1, Tab 1). Knowing about the fact that all parts of a disc have different conditions of work, the anterior, posteriori and central parts of encircling structure of the disc were thought to be the most crucial. All the tests were made with the use of an all-purpose strength machine Zwick, at pile characteristics of force change in scope between 0 and 3 N at speed of 1 N/s. These are the influence of individual cycles on the shape of the hysteresis loop and the changes of damping properties chich in a very important way determinate distribution of the load on the acetabu- lum bone and the head of the mandible, which were evaluated here. On the basis of the stress-strain results (Fig. 4), stiffness and the effective Young module of tissues in the measurement area were estimated. It was proved that stress-strain characteristics of discs' tissues significantly depend on the area of measurement and the history of load. The largest changes can be noticed during the first four cycles, and the one which may be called the stable is the fifth cycle of load. The result shows that it is necessary to verify all data inserted to bank conditions which were obtained through the static tests, and that it is inappropriate to take the average material characteristics to use on the whole volume of the disc. While loading discs, completely different valu- es of the effective Young module were obtained for separate parts. They were like these: for the posterior part 4.44 MPa, for the central part 1.97 MPa and for the anterior part 2.99 MPa (Tab. 2). The recorded cycles which included changes of force and strain were the cause to form a mathematical model of material of which the disc of the temporomandibular joint is made. The greatest falls in the width of the hysteresis loop was noticed in the anterior and posterior areas. In the posterior area for the tenth cycle the surface of the hysteresis is almost twice as small as it was in the second cycle, whereas In the anterior area the surface makes smaller almost three times (Tab. 4). In fact the growth of stiffness leads to worsening of dampening properties of the joint disc tissues. The stiffest part of the disc is its posterior part, where the stiffness in the fifth cycle of load was 87.1 N/mm. The central disc part was the least stiff and it took only 38.7 N/mm (Tab. 2). The compliance of the model cycles of the disc work was confirmed by verification during chich the results of numerical simulations with the test data were compared. His allows to state that the reological model with its identified parameters repro- duces the cycles of the disc work very well.

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Wpływ przecięcia tkanek na wyniki badań właściwości mechanicznych krążków stawu skroniowo-żuchwowego

Chladek W., Czerwika I.

Engineering of Biomaterials

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2007

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Vol. 10, no. 67-68

16-18