Functional Changes of the Temporomandibular Joint Mechanoreceptors Induced by a Lateral Mandibular Shift in Rats

Degeneration of the articulating surfaces and pain associated with temporomandibular joint (TMJ) dysfunction are the primary symptoms of TMJ disorders (TMDs), where normal life activities such as eating, talking, and even sleeping may be drastically impaired [1–3]. To accelerate the discovery of effective therapeutic interventions for the treatment of TMD pain, we have been establishing a novel non-invasive approach for objectively assessing the presence of joint hypersensitivity. Our approach to identify chronic joint pain is based on evidence that all of the etiological factors associated with TMD pain implicate remodeling and degeneration of the joint in response to alterations in motion and loading. The injury model used for this study was a reversible, mechanical model through splint placement on the molars. It is hypothesized that arthrokinematic analysis will identify a specific pattern of functional changes that constitute a signature for the presence of irreversible damage.

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Functional Changes of Temporomandibular Joint Mechanoreceptors Induced by Reduced Masseter Muscle Activity in Growing Rats

The Angle Orthodontist ◽

10.2319/081108-424.1 ◽

2009 ◽

Vol 79 (5) ◽

pp. 978-983 ◽

Cited By ~ 4

Author(s):

Takayoshi Ishida ◽

Tadachika Yabushita ◽

Kunimichi Soma

Keyword(s):

Temporomandibular Joint ◽

Muscle Activity ◽

Masseter Muscle ◽

Growth Period ◽

Control Group ◽

Functional Changes ◽

Male Wistar Rats ◽

Masseter Muscles ◽

Experimental Group ◽

Indirect Stimulation

Abstract Objective: To determine the influence of masseter muscle activity during growth on the functional characteristics of temporomandibular joint (TMJ) mechanoreceptors. Materials and Methods: Sixty-six 3-week-old male Wistar rats were divided into an experimental group, in which the masseter muscles were bilaterally resected at 3 weeks of age, and a control group. Single-unit activities of the TMJ mechanoreceptors were evoked by indirect stimulation of passive jaw movement. Electrophysiologic recordings of TMJ units were made at 5, 7, and 9 weeks of age. Results: During this period, the firing threshold of the TMJ units was significantly lower and the maximum instantaneous frequency of the TMJ units was significantly higher in the experimental group than in the control group. Conclusion: Reduced masseter activity during the growth period alters the response properties of TMJ mechanoreceptors.

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Functional changes in the temporomandibular joint mechanoreceptors associated with experimentally induced condylar resorption in rats

The Angle Orthodontist ◽

10.2319/020420-80.1 ◽

2020 ◽

Vol 90 (6) ◽

pp. 831-836

Author(s):

Satomi Naito ◽

Chiho Kato ◽

Tadachika Yabushita ◽

Takashi Ono

Keyword(s):

Temporomandibular Joint ◽

Single Unit ◽

Compressive Force ◽

Firing Frequency ◽

Control Group ◽

Gasserian Ganglion ◽

Firing Threshold ◽

Functional Changes ◽

Force Loading ◽

Experimentally Induced

ABSTRACT Objectives To evaluate the influence of experimentally induced progressive condylar resorption (PCR) on temporomandibular joint (TMJ) mechanoreception. Materials and Methods Twenty 13-week-old male albino Wistar rats were divided equally into control and PCR groups. A compressive force was loaded on the left TMJ of PCR group rats to induce condylar resorption. Single-unit activities of TMJ mechanoreceptors were also induced through passive jaw movement. Recording was performed for the left Gasserian ganglion at 3 days and 1 week after the establishment of PCR group. The effects of PCR on TMJ units were assessed by measuring the firing threshold, maximum instantaneous firing frequency, and average firing frequency. Results Compared with the control group, there were no significant differences in the firing threshold of the PCR group after 3 days. The thresholds were significantly higher 1 week after compressive force loading on the condyle. The maximum instantaneous firing frequencies and the average firing frequencies showed no significant differences after 3 days. However, these were significantly lower 1 week after compressive force loading. Conclusions The findings suggest that compressive force loading on the condyle may influence the function of TMJ mechanoreceptors.

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MRI IN DIAGNOSIS OF CRANIOMANDIBULAR DYSFUNCTIONS

Science and Innovations in Medicine ◽

10.35693/2500-1388-2016-0-2-33-37 ◽

2016 ◽

Vol 1 (2) ◽

pp. 33-37

Author(s):

IV V Tokarevich ◽

DV V Piskun ◽

TV V Ilyina

Keyword(s):

Temporomandibular Joint ◽

Masticatory Muscles ◽

Articular Disc ◽

Resonance Imaging ◽

Functional Capability ◽

Contrast Resolution ◽

Functional Changes ◽

Functional Parameters ◽

Muscular Pain ◽

Reduction Of Pain

Visualization of the temporomandibular joint (TMJ) is constantly evolving with the improvement of technology. Magnetic resonance imaging is commonly used to evaluate the TMJ due to the high contrast resolution and the ability to obtain dynamic images to demonstrate the functional capability of the joint. Aim - to determine the functional changes after TMJ splint therapy conducted at various stages of intra-articular disorders. Data and methods. We conducted a survey, clinical examination and MRI of TMJ of 37 patients with temporomandibular disorders (TMD). Two groups of patients were formed according to the received MR picture of TMJ. Results. The study highlighted that regression of pain in TMJ and masticatory muscles, and normalization of functional parameters after splint rehabilitation occur more often in the first group of patients, who have disorders of the articular disc of the TMJ. Conclusion. In both groups of patients we noted positive dynamics of functional parameters of TMJ, reduction of pain in TMJ and masticatory muscles. Though 36,8% of the second group of patients, who have bone remodeling of TMJ condyles, didn’t show dynamics of functional parameters. Consequently, the use of splint in one third of patients with temporomandibular joint condyles destruction is effective for TMJ and muscular pain reduction.

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Optimization of treatment tactics of patients with distal occlusion of dentition according to results of functional, clinical and X-ray studies of temporomandibular joint

Medical alphabet ◽

10.33667/2078-5631-2019-3-23(398)-58-63 ◽

2019 ◽

Vol 3 (23) ◽

pp. 58-63 ◽

Cited By ~ 7

Author(s):

V. V. Konnov ◽

D. A. Domenyuk ◽

I. V. Ivanyuta ◽

S. О. Ivanyuta

Keyword(s):

Temporomandibular Joint ◽

Research Methods ◽

Laboratory Research ◽

Orthopedic Treatment ◽

X Ray ◽

Functional Changes ◽

Radiological Features ◽

Temporomandibular Joints ◽

High Prevalence ◽

Distal Occlusion

The high prevalence of structural and functional lesions of the temporomandibular joints in adults, reaching 76 %, as well as the complexity of diagnosis and treatment of musculo-articular dysfunctions, determine the relevance of further research in this section of modern dentistry. Defects of the dentition in combination with distal occlusion are accompanied by structural and functional changes in the temporomandibular joint. The object of the study was 180 patients with dentition defects in combination with distal occlusion. As a result of the application of clinical and laboratory research methods, three variants of the temporomandibular joint were identified, the clinical and radiological features of the pathology studied were determined, and an algorithm for orthodontic and orthopedic treatment of this pathology was proposed depending on the selected temporomandibular joint.

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Changes in the dentition with increased tooth abrasion

Стоматология для всех ◽

10.35556/idr-2020-3(92)30-34 ◽

2020 ◽

pp. 30-34

Author(s):

D.A. Stepanov ◽

V.S. Leibenko ◽

E.A. Stepanov ◽

E.A. Koretskaya ◽

L.A. Zyulkina

Keyword(s):

Temporomandibular Joint ◽

Diagnosis And Treatment ◽

Maxillofacial Region ◽

Functional Changes ◽

Jaw Bones ◽

Tooth Abrasion

In the article the analysis of the changes in the dentoalveolar system occurring with increased abrasion of the teeth is carried out, the features of these changes and the compensatory capabilities of the dentoalveolar system with pathological abrasion are considered. It was concluded that the observed rearrangements on the part of many structures of the maxillofacial region (jaw bones, temporomandibular joint, teeth, muscles) should be established during diagnosis and treatment should be planned taking into account the morphological and functional changes that have arisen on the part of all elements of the dentition, which will help improve the effectiveness of treatment.

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MORPHO-FUNCTIONAL CHANGES IN TEMPOROMANDIBULAR JOINT IN CASE OF DENTAL DEFECTS COMPLICATED BY LOWER JAW DISTAL S

Archiv Euromedica ◽

10.35630/2199-885x/2019/9/3.28 ◽

2019 ◽

Vol 9 (3) ◽

pp. 100-102

Author(s):

Valeriy Konnov ◽

Natalia Bulkina ◽

Anush Arushanyan ◽

Ekaterina Pichugina ◽

Tatyana Matitsyna ◽

...

Keyword(s):

Temporomandibular Joint ◽

Functional Changes ◽

Lower Jaw

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Biomechanical evaluation of the human mandible after temporomandibular joint replacement under different biting conditions

Scientific Reports ◽

10.1038/s41598-021-93564-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Manuel Pinheiro ◽

Robin Willaert ◽

Afaq Khan ◽

Anouar Krairi ◽

Wim Van Paepegem

Keyword(s):

Temporomandibular Joint ◽

Animal Studies ◽

Principal Strain ◽

Implant Design ◽

Study Patient ◽

Patient Specific ◽

Functional Changes ◽

Masticatory Function ◽

The Impact

AbstractTemporomandibular joint (TMJ) replacement with an implant is only used when all other conservative treatments fail. Despite the promising short-term results, the long-term implications of TMJ replacement in masticatory function are not fully understood. Previous human and animal studies have shown that perturbations to the normal masticatory function can lead to morphological and functional changes in the craniomaxillofacial system. A clearer understanding of the biomechanical implications of TMJ replacement in masticatory function may help identify design shortcomings that hinder their long-term success. In this study, patient-specific finite element models of the intact and implanted mandible were developed and simulated under four different biting tasks. In addition, the impact of re-attaching of the lateral pterygoid was also evaluated. The biomechanics of both models was compared regarding both mandibular displacements and principal strain patterns. The results show an excessive mediolateral and anteroposterior displacement of the TMJ implant compared to the intact joint in three biting tasks, namely incisor (INC), left moral (LML), and right molar (RML) biting. The main differences in principal strain distributions were found across the entire mandible, most notably from the symphysis to the ramus of the implanted side. Furthermore, the re-attachment of the lateral pterygoid seems to increase joint anteroposterior displacement in both INC, LML and RML biting while reducing it during LGF. Accordingly, any new TMJ implant design must consider stabilising both mediolateral and anteroposterior movement of the condyle during biting activities and promoting a more natural load transmission along the entire mandible.

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IGF1 Signaling in Temporomandibular Joint Fibrocartilage Stem Cells Regulates Cartilage Growth and Homeostasis in Mice

10.1101/2021.11.19.469277 ◽

2021 ◽

Author(s):

Ruiye Bi ◽

Xueting Luo ◽

Qianli Li ◽

Peiran Li ◽

Yi Fan ◽

...

Keyword(s):

Stem Cell ◽

Temporomandibular Joint ◽

Pathological Condition ◽

Cartilage Thickness ◽

Tunel Staining ◽

Mice Model ◽

Cartilage Growth ◽

Functional Changes ◽

Cell Functions ◽

Safranine O

Objective: Investigate functional roles of Igf1 in fibrocartilage stem cell (FCSC) for temporomandibular joint (TMJ) cartilage growth and homeostasis. Methods: Gli1-CreER+; RosaTdTomato mice were used for validating FCSCs lineage labeling efficiency. In Gli1-/Col2-CreER+; Igf1fl/fl mice, TMJ cartilage morphological and functional changes were characterized at 4 weeks and 5 months after Igf1 deletion. H&E, Safranine O and immuno-histochemistry staining were performed. FCSCs specificity were characterized using EdU and TUNEL staining. A unilateral anterior crossbite (UAC) mouse model was generated for mimicking TMJ osteoarthritis status. Results: In Gli1-CreER+; RosaTdTomato mice, RFP labeled FCSCs showed favorable proliferative capacity. 4 weeks after Igf1 deletion, Gli1+ and Col2+ cell lineages led to distinct pathological changes of TMJ cartilage morphology. A more serious reduction of cartilage thickness and cell density were found in the superficial layers in Gli1-CreER+; Igf1fl/fl mice. 5 months after Igf1 deletion, more severe disordered cell arrangement in TMJ cartilage were found in both groups with Gli1+ and Col2+ specific deletion of Igf1. Immunostaining showed that PI3K/Akt signaling pathway was blocked in the superficial layers of TMJ in Gli1-CreER+; RosaTdTomato mice. Finally, deletion of Igf1 in FCSCs significantly aggravated osteoarthritis (OA) phenotypic changes in TMJ in UAC mice model, characterized in decreased cartilage thickness, cell numbers and loss of extracellular matrix secretion. Conclusion: Igf1 deletion disrupted stem cell functions of FCSCs, leading to disordered cell distribution during TMJ growth, as well as exaggerated the OA process in TMJ under pathological condition. In TMJ cartilage, Igf1 expression in FCSCs is critical for PI3K/Akt activation, which may be involved in regulating FCSCs self-renewal and differentiation.

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Morphological Changes in the Rat Granulosa Cell Surface During Differentiation Induced by Estradiol and Gonadotropins

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079851 ◽

1977 ◽

Vol 35 ◽

pp. 484-485

Author(s):

P. Bagavandoss ◽

JoAnne S. Richards ◽

A. Rees Midgley

Keyword(s):

Cell Surface ◽

Granulosa Cell ◽

Morphological Changes ◽

Follicular Development ◽

Female Rats ◽

Functional Changes ◽

Group 4 ◽

Group 3 ◽

Group 5 ◽

Group 2

During follicular development in the mammalian ovary, several functional changes occur in the granulosa cells in response to steroid hormones and gonadotropins (1,2). In particular, marked changes in the content of membrane-associated receptors for the gonadotropins have been observed (1).We report here scanning electron microscope observations of morphological changes that occur on the granulosa cell surface in response to the administration of estradiol, human follicle stimulating hormone (hFSH), and human chorionic gonadotropin (hCG).Immature female rats that were hypophysectcmized on day 24 of age were treated in the following manner. Group 1: control groups were injected once a day with 0.1 ml phosphate buffered saline (PBS) for 3 days; group 2: estradiol (1.5 mg/0.2 ml propylene glycol) once a day for 3 days; group 3: estradiol for 3 days followed by 2 days of hFSH (1 μg/0.1 ml) twice daily, group 4: same as in group 3; group 5: same as in group 3 with a final injection of hCG (5 IU/0.1 ml) on the fifth day.

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