Wyniki wyszukiwania - Biblioteka Nauki

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

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Zhu Y. , Zheng F. , Gong Y. , Yin D. , Liu Y.

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tom 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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Ocena zaburzeń stawu skroniowo – żuchwowego w aspekcie aktywności bioelektrycznej

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Szymańska D.

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tom 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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Functional disturbances of the masticatory apparatus – diagnosis and treatment

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Kogut G. , Kwolek A.

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tom 10(1)

44-56

PL

Diagnostyka zaburzeń czynnościowych układu ruchowego narządu żucia stwarza wielokrotnie duże trudności. Oprócz dokładnego wywiadu i badania klinicznego pacjenta, konieczna jest dokładna analiza zwarcia i czynności ruchów żuchwy pacjenta. Rutynowo wykonywane są badania radiologiczne stawu skroniowo-żuchwowego, które uwidaczniają patologiczne zmiany kształtu powierzchni stawowych, jak również nieprawidłowe położenie względem siebie tkanek twardych. W przypadkach ciężkich postaci zaburzeń należy wykonać dalsze badania obrazujące (tomografię komputerową, rezonans magne tyczny). Leczenie tych zaburzeń obejmuje wiele etapów postępowania. Pierwszym i ważnym elementem jest zwalczenie parafunkcji, po uprzednim uświadomieniu pacjentowi faktu ich uprawiania. Stomatologiczne leczenie przyczynowe ma na celu przywrócenie prawidłowych stosunków wewnątrzustnych (obejmujących zęby własne pacjenta lub uzupełnienia protetyczne), zewnątrzustnych (stawów skroniowo-żuchwowych) oraz przywrócenie prawidłowej czynności mięśni narządu żucia. We wstępnym okresie leczenia stosuje się różnego rodzaju szyny zgryzowe i aparaty odciążające oraz szyny stabilizujące, które umożliwiają uzyskanie i utrzymanie prawidłowego położenia krążków stawowych i głów żuchwy. W przypadkach powikłanych innymi bólami wdraża się leczenie farmakologiczne. Metody fizykoterapeutyczne są stosowane jako terapia osłonowa. Prostymi metodami, stosowanymi nawet przez samych pacjentów, jest ciepłolecznictwo (ciepło wilgotne i suche) i krioterapia. Zastosowanie znajdują również: elektrolecznictwo, leczenie ultradżwiękami, laserem niekoenergetycznym. Wspomagająco działa masaż klasyczny, masaż tkanki łącznej i automasaż mięśni żucia. W uzyskaniu zmiany zachowania pocjenta pomocna może być metoda biologicznego sprzężenia zwrotnego, stosowana równocześnie z ćwiczeniami aktywnymi i biernymi. Pozytywne wyniki leczenia zaburzeń układu ruchowego narządu żucia uzyskuje się u 60-80% leczonych pacjentów, a profilaktyka obejmuje głównie przeciwdziałanie parafunkcjom żuchwy.

EN

Diagnosis of the masticatory motor system functional disturbances frequently creates significant difficulties. Aside from detailed medical history and examination of a patient, precise analysis of occlusion and lower jaw movements is necessary. Routine radiological examinations of the temporo-mandibular joint reveal pathological changes of joint surfaces shape, as well as malposition of hard tissues. In cases of severe forms of dysfunction, further imaging studies should be performed (computed tomography, magnetic resonance imaging). Treatment of these dysfunctions includes many procedures. The first and important element is combating parafunctions after previously having made the patient aware of the fact of their existence. Stomatologic causal treatment aims at restoring correct intraoral (including patient's own teeth or prosthetic restoration) and extraoral (temporo-mandibular joints) relationships and restoring appropriate activity of the masticatory apparatus muscles. During the initial phase of treatment, various types of oclusion splints, relieving apparatuses and stabilising splints are used, which enable obtaining and maintaining correct position of articular disc and heads of the mandible. In cases complicated by severe pain states, appropriate pharmacological treatment is implemented. Physiotherapeutic methods are used as protective therapy. Simple methods, used even by patients themselves, include warmth-treatment (humid warmth or dry warmth) and cryotherapy. Treatment with physical agents such as electrical current, ultrasound and low-energy laser therapy is also used. Classical massage, connective tissue massage and auto-massage of the masseter muscles act adjunctively. The biofeedback method used simultaneously with passive and active exercises can also be helpful in obtaining a change in patient's behaviour,. Positive results of the therapy of the masticatory apparatus motor system dysfunctions are achieved in 60-80% of the treated patients, while prophylaxis involves mainly counteracting parafunctions of the mandible.

4

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

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Vilimek M. , Horak Z. , Baca W.

Acta of Bioengineering and Biomechanics

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2016

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

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Shu J. , Wang Q. , Ma H. , Teng H. , Zheng T. , Liu Z.

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tom 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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An investigation of mandibular asymmetries in patients with TMD as an element of the design of dental polymeric devices for early rehabilitation

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Tegnander T. , Wojtek P. , Żmudzki J. , Chladek G.

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tom Vol. 120, nr 2

84--91

EN

Purpose It is essential to acquire data that will allow the detection of problems occurring within anatomical material structures before the appearance of obvious symptoms of TMD and to design materials and devices in order to take preventive measures. The aim was to examine if asymmetrical changes in the mandible ramus height may indicate TMD. Hypotheses were that asymmetry may be an indicator of TMD and that trauma at a young age may lead to growth changes in the height of the mandibular ramus, hence asymmetries. Design/methodology/approach An investigated group consisted of 65 patients with TMD, and the control group consisted of 20 patients with no TMD. The images were obtained with a Durr Vista Panoramic system. The differences in the height of the ramus were calculated. Statistical analysis of the results was performed. Findings Most patients diagnosed with TMD experienced traumatic events in childhood, while no similar cases were reported in the control group. Significant asymmetry was also found in the TMD group. The gender of the patients did not influence the asymmetries. There was no correlation between the age of the patients and the asymmetry in patients with TMD. Still, the correlation occurred in the control group due to significant asymmetries for the youngest patients.