scholarly journals Experimentally Created Nonbalanced Occlusion Effects on the Thickness of the Temporomandibular Joint Disc in Rats

2009 ◽  
Vol 79 (1) ◽  
pp. 51-53 ◽  
Author(s):  
Lei Sun ◽  
Meiqing Wang ◽  
Jianjun He ◽  
Lei Liu ◽  
Shuang Chen ◽  
...  

Abstract Objectives: To test the hypothesis that experimentally created physiologically nonbalanced occlusion will not affect the thickness of the temporomandibular joint (TMJ) discs in rats. Material and Methods: Twenty-four 8-week-old Sprague-Dawley rats were equally divided into a control group that was left untreated and an experimental group where a nonbalanced occlusion was created. Elastic rubber bands, 1 mm in diameter, were inserted and 1 week later were replaced by plastic material between the first and the second molars of the left maxillary and the right mandibular dentitions to move the first molars about 0.8 mm mesially. This created and maintained a physiologically nonbalanced occlusion. The animals were euthanized 8 weeks later, and the TMJ disc thickness was measured on histologically prepared slices using an electronic meter. Two-way univariate analysis of variance was used to compare the groups (α level = .05). Results: The intermediate zone was thicker in the experimental group than in the control group (P = .003), but no differences were found between groups regarding the anterior and posterior bands. There were no significant sex-related effects on this observation. Conclusion: The hypothesis is rejected. The results indicate that the intermediate zone of rat TMJ disc has the ability to adapt to the alteration of the space between condyle and fossa caused by occlusion changes. Further studies on larger groups that are followed for longer times are needed.

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Vincent P. Willard ◽  
Kerem N. Kalpakci ◽  
Andrew J. Reimer ◽  
Kyriacos A. Athanasiou

Understanding structure-function relationships in the temporomandibular joint (TMJ) disc is a critical first step toward creating functional tissue replacements for the large population of patients suffering from TMJ disc disorders. While many of these relationships have been identified for the collagenous fraction of the disc, this same understanding is lacking for the next most abundant extracellular matrix component, sulfated glycosaminoglycans (GAGs). Though GAGs are known to play a major role in maintaining compressive integrity in GAG-rich tissues such as articular cartilage, their role in fibrocartilaginous tissues in which GAGs are much less abundant is not clearly defined. Therefore, this study investigates the contribution of GAGs to the regional viscoelastic compressive properties of the temporomandibular joint (TMJ) disc. Chondroitinase ABC (C-ABC) was used to deplete GAGs in five different disc regions, and the time course for >95% GAG removal was defined. The compressive properties of GAG depleted regional specimens were then compared to non-treated controls using an unconfined compression stress-relaxation test. Additionally, treated and non-treated specimens were assayed biochemically and histologically to confirm GAG removal. Compared to untreated controls, the only regions affected by GAG removal in terms of biomechanical properties were in the intermediate zone, the most GAG-rich portion of the disc. Without GAGs, all intermediate zone regions showed decreased tissue viscosity, and the intermediate zone lateral region also showed a 12.5% decrease in modulus of relaxation. However, in the anterior and posterior band regions, no change in compressive properties was observed following GAG depletion, though these regions showed the highest compressive properties overall. Although GAGs are not the major extracellular matrix molecule of the TMJ disc, they are responsible for some of the viscoelastic compressive properties of the tissue. Furthermore, the mechanical role of sulfated GAGs in the disc varies regionally in the tissue, and GAG abundance does not always correlate with higher compressive properties. Overall, this study found that sulfated GAGs are important to TMJ disc mechanics in the intermediate zone, an important finding for establishing design characteristics for future tissue engineering efforts.


2020 ◽  
Vol 14 (03) ◽  
pp. 124-127
Author(s):  
Somia Iqbal ◽  
Noman Sadiq ◽  
Saad Siddiqui ◽  
Hira Iqbal

Background: Obesity is a prevailing metabolic disorder that affects the functioning of the male reproductive system. Excessive adipose tissue enhances reactive oxygen species generation and is linked with male infertility. Spinach has demonstrated antioxidant effects. The present study was conducted to determine the antioxidant effects of spinach on sperm parameters in obese Sprague Dawley rats. Subjects and methods: This randomized control study was conducted at the animal house of the National Institute of Health Islamabad, Islamic International Medical College, Cosmesurge International Hospital, Rawalpindi, and Apollo lab, Islamabad, Pakistan from April 2016 to March 2017. Forty male Sprague Dawley rats having an age of 8 weeks and weight 160-200g were tagged from number 1 to 40. Every third rat was randomly allocated to control Group A (n=13) and remaining into the Experimental group (n=27). Rats of control Group A was given a standard diet while a high-fat diet was given to Experimental group rats to induce obesity for the duration of six weeks. Weight (g) was measured weekly and obesity was confirmed when rats attain more than 20% weight when compared with that of rats of control Group A. Then, after obesity induction, the experimental group was alienated into the obesity control group (Group B) and spinach treated group (Group C). For sample, rats of Group A and Group B were sacrificed, and the cauda epididymis of each rat was placed in a Petri dish containing normal saline and cut into pieces to allow the release of sperm and then sperm parameters (sperms concentration, motility, and morphology) were recorded under the microscope. Then, spinach (5% hot water extract) along with the persistence of fat diet was administered to Group C for 4 weeks and finally, sperm parameters were measured in this group. Results: Sperm concentration/ml, motility (%), and normal morphology (%) of Group B rats were significantly decreased as compared to Group A rats. However, sperm concentration/ml, motility (%), and normal morphology (%) of Group C (spinach treated group) rats was significantly increased (p<0.001) as compared to Group B (obesity control group) rats after administering spinach. Conclusion: The addition of Spinach in a normal diet regimen restores normal sperm morphology, improves sperm motility and concentration.


Author(s):  
Mahasin Gad Alla Mohamed ◽  
Khalida Mohammed Mahmoud ◽  
Abeer Amir Bashir

The aim of the research was to investigate the effectiveness of a computer based on photoshop in design and decoration and its impact on emotional intelligence among children in the age group (11-17 years). To achieve the research objectives, the researchers chose the quasi-experimental design with equal groups, the control group and the experimental group. The sample size was (44) students, (14) males and (30) females, who were chosen by random stratification method from the middle and high school levels in Jazan region in the age group (11-17). They were distributed into two equal groups (22) students for each of the control and experimental group. The researchers used the Bar-On scale for emotional intelligence in addition to the training program. The Statistical Package for Social Sciences (SPSS) program was used for analyzing data. The two-tailed T-Test was chosen to detect the differences between the binary groups and the univariate analysis. Variation: to detect differences between the interaction groups and the post-LSD test to determine the direction of the differences between groups of variable interaction (group x application). The research reached the following results: there are statistically significant differences in the average scores of children of age (11-17 years) on the emotional intelligence scale pre and post the application of the program, and there are statistically significant differences in the average performance of the experimental group on the emotional intelligence scale due to gender, and there are significant differences statistical differences in the average performance of the experimental group on the emotional intelligence scale due to age, and there are statistically significant differences in the average scores of 11-17 year old children on the emotional intelligence scale between the groups of variables of program application and type of education.


2020 ◽  
Author(s):  
Wei Lin ◽  
Yike Dai ◽  
Jinghui Niu ◽  
Chongyi Fan ◽  
Xunkai Feng ◽  
...  

Abstract Background As one of the lower extremity deformities in human, trochlear dysplasia is a commonly encountered disease. However, the molecular mechanism of cartilage degeneration in trochlear dysplasia is indefinite yet. It was apparent to all that PI3K/AKT signal pathway is extremely significant in regulating the pathophysiological process of cartilage degeneration. The purpose of this research is to discuss the correlation between PI3K/AKT signal pathway and trochlear dysplasia cartilage degeneration. Materials and methods 120 female Sprague-Dawley rats at 4 weeks of age were separate into control group and experimental group randomly. The distal femurs were isolated from the experimental and unsurgeried control group at the point of the 4, 8, 12 weeks, correspondingly. Micro-CT and histological examination were carried out to investigate the anatomical structure and cartilage changes of the trochlear. Subsequently, the expression of PI3K/AKT, TGFβ1 and ADAMTS-4 in cartilage were investigated by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR). Results In the experimental group, the trochlear dysplasia model was successfully established at 8 weeks after surgery. Moreover, the cartilage degeneration was found from 8 weeks, with continued higher protein and mRNA expression of PI3K/AKT, TGFβ1 and ADAMTS-4 compared with the control group. Conclusions This research suggested that patellar instability may lead to trochlear dysplasia in growing rats. Moreover, trochlear dysplasia was probably one of the causes of patellofemoral osteoarthritis and the cartilage degeneration in trochlear dysplasia might be associate with activation of PI3K/AKT signal pathway. However, more research was required to clarify the underlying mechanisms.


2009 ◽  
Vol 79 (5) ◽  
pp. 978-983 ◽  
Author(s):  
Takayoshi Ishida ◽  
Tadachika Yabushita ◽  
Kunimichi Soma

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.


Author(s):  
Catherine K. Hagandora ◽  
Alejandro J. Almarza

The temporomandibular joint (TMJ) is a synovial, bilateral joint formed by the articulation of the condyle of the mandible and the articular eminence and glenoid fossa of the temporal bone. The articulating tissues of the joint include the TMJ disc and the mandibular condylar cartilage (MCC). It is estimated that 10 million Americans are affected by TMJ disorders (TMDs), a term encompassing a variety of conditions which result in positional or structural abnormalities in the joint. [1] Characterization of the properties of the articulating tissues of the joint is a necessary prequel to understanding the process of pathogenesis as well as tissue engineering suitable constructs for replacement of damaged joint fibrocartilage. Furthermore, the current literature lacks a one-to-one comparison of the regional compressive behavior of the goat MCC to the TMJ disc.


2018 ◽  
Vol 10 (446) ◽  
pp. eaaq1802 ◽  
Author(s):  
Natalia Vapniarsky ◽  
Le W. Huwe ◽  
Boaz Arzi ◽  
Meghan K. Houghton ◽  
Mark E. Wong ◽  
...  

Treatments for temporomandibular joint (TMJ) disc thinning and perforation, conditions prevalent in TMJ pathologies, are palliative but not reparative. To address this, scaffold-free tissue-engineered implants were created using allogeneic, passaged costal chondrocytes. A combination of compressive and bioactive stimulation regimens produced implants with mechanical properties akin to those of the native disc. Efficacy in repairing disc thinning was examined in minipigs. Compared to empty controls, treatment with tissue-engineered implants restored disc integrity by inducing 4.4 times more complete defect closure, formed 3.4-fold stiffer repair tissue, and promoted 3.2-fold stiffer intralaminar fusion. The osteoarthritis score (indicative of degenerative changes) of the untreated group was 3.0-fold of the implant-treated group. This tissue engineering strategy paves the way for developing tissue-engineered implants as clinical treatments for TMJ disc thinning.


Author(s):  
Vladimir Momčilović ◽  
Zoran Momčilović ◽  
Srđan Nikolić

In this paper, the authors presented a study aimed at determining the impact of coordination and speed training programs on morphological characteristics of classroom pupils. The sample of respondents included primary school pupils from Nis, aged 9 and 10 (± 6 months). The sample of 64 respondents was divided into two groups, an experimental and control group, 32 pupils in each group. The respondents of the experimental group were involved in the training process of exercising coordination and speed in additional PE classes, while the control group was involved only in regular PE classes. The results of the multivariate analysis of variance and the univariate analysis of variance showed that there are statistically significant differences in the morphological characteristics of the experimental group of respondents in the final measurement compared to the control group respondents  in the skin abdomen (ANTRB), the foreskin of the upper arm  (ANNAD), and the skin of the lower leg (ANPTK).


2018 ◽  
Vol 9 ◽  
pp. 24
Author(s):  
Carolin Parlina ◽  
Erni H Purwaningsih ◽  
Ahmad Aulia Jusuf ◽  
Retno Widayati

Objective: This study aimed to show the impact of the ZOL in VCO gel (Ge-ZOL) on the extent of osteoclasts apoptosis.Methods: The study used 27 Sprague-Dawley rats which were divided into three groups: Nine rats in the experimental group were given 40 µg of Ge-ZOL, nine rats in the control group were given VCO emulsion gel without ZOL (Ge-), and nine rats in the normal group were not given any treatment. The gel was applied to the buccal mucosa using a cotton bud for 2 min at hour of 0, 4, and 8 on days 0, 1, 2, 3, and 4. The rats were sacrificed on days 1, 3, and 5, and then, evaluated by immunohistochemical caspase-3 staining.Result: The number of apoptotic osteoclast cells in the experimental group was significantly higher than in the control and normal groups (p<0.05). The number of apoptotic osteoclast cells in the experimental group on the day 1 was significantly higher than on the days 3 and 5 (p<0.001).Conclusion: The application of Ge-ZOL to the buccal mucosa proven to improve the number of apoptotic osteoclast cells in the experimental group on the day 1, and this number was higher than on the days 3 and 5.


1985 ◽  
Vol 57 (1) ◽  
pp. 51-57 ◽  
Author(s):  
H. Cake ◽  
I. Lenzer

To study the effects of paternal chronic low-dosage ethanol administration on fetal outcome, male Sprague-Dawley rats received either .6g/ kg ethanol (experimental group) or water (control group). Males were mated between the fourth and seventh weeks of treatment. Pregnancies were terminated on gestational Day 21. Cerebral weight and placental weight in offspring of the ethanol-treated males were significantly larger than those of control males. There was no effect on litter size. Experimental females (dams that became pregnant when paired with an ethanol-treated male) were significantly heavier than control dams. Since these pairings were random at every mating, the experimental males appeared to have been more successful impregnating heavier than lighter females.


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