The temporomandibular joint (TMJ) helps move the mandible and handle the forces associated with mastication. Much like other joints in the body, the TMJ can be afflicted with disorders that impair its function. Osteoarthritis (OA), one of the most common degenerative joint diseases worldwide, has been implicated as a prevalent temporomandibular disorder with limited treatment options. Fibroblast growth factor 2 (Fgf2), a gene important in bone remodeling, has been shown to lead to murine knee OA phenotypes in its germline ablation studies. In this study, the articular chondrocyte-specific ablation of the gene is studied in the temporomandibular joint condylar cartilage of female mice using a Col2CreERT2 knockout system. Micro-CT imaging suggested phenotypic changes in the condylar head samples of the conditional knockout samples in comparison to the control. Safranin o stains on frozen sections revealed phenotypic changes in cell morphology in the deeper layers of the cKO cartilage tissues in comparison to the control. Immunohistochemistry staining indicated a significant decrease in BMP2 protein expression and increasing trends in proteins responsible for cartilage degradation such as MMP13 in cKO samples in comparison to the control. These results suggest that the conditional ablation of Fgf2 results in phenotypic disruptions in the condylar cartilage of the TMJ. Further studies would be needed to indicate the validity behind these apparent disruptions and to further evaluate the molecular markers responsible for these changes.

This thesis discusses the illness experience of people living with chronic pain resulting from Temporomandibular disorders (TMD). The literature discusses various aspects of the experience of chronic pain, but there is little research reported specifically on the experience of living with TMD. Using analysis of sufferers' narratives, I discuss common explanatory models and coping strategies. I then present aspects of the bodily experience of TMD as seen in people with comorbid illnesses. The personal or mental aspects of TMD are explored, particularly in terms of fear, anxiety, and hope for the future. Lastly, the broader impacts of TMD are explored through sufferers' relationships with friends and family, and sufferers' ability to function in social contexts. It is concluded that TMD impacts many areas of sufferers' lives, and that the lived experience extends beyond diagnosis and treatment seeking to include the day to day management of TMD pain.

Abstract The fact that the lateral pterygoid muscle (LPM) and related symptoms play an important role in temporomandibular disorders (TMD) is widely recognized. In the study reported here, the LPM was investigated by magnetic resonance imaging (MRI) of patients with TMD. The visibility of the LPM in MRI with different projections was analyzed and a new imaging projection, condyle-the lateral pterygoid muscle projection (CLPM), for the LPM in MRI was introduced. Normal and abnormal findings of the LPM was compared with clinical symptoms of TMD. Compared with sagittal imaging of temporomandibular joint (TMJ), CLPM images and most of the oblique sagittal imaging were able to show the LPM clearly. Hypertrophy, atrophy and contracture of the LPM were found in TMJs either with disc in normal position or with disc displacements. Pathological changes of the superior belly and hypertrophy of the inferior belly combined with various pathological changes of the superior belly were the most frequently observed abnormal imaging findings of the LPM in TMD. The pathological changes of the LPM were associated with the main clinical symptoms of TMD. In patients with symptomatic condyle hypermobility, the pathological changes of the LPM and related symptoms were associated with the clinical symptoms of TMJs with disc in normal position. The imaging abnormalities of the LPM were common in TMJs with disc displacements and seemed to be fewer in condyle hypomobility cases in TMJs with anterior disc displacement with non-reduction (ADDnr). However, normal imaging of the LPM was also found in TMJs with severe osteoarthritic changes and disc displacement. The recognition of muscle alterations may lead to a more specific diagnosis and improve the understanding of the clinical symptoms and disease pathophysiology of TMD.

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BACKGROUND: Osteoarthritis (OA) is the most common degenerative joint disease which affects the joint structures leading to disability. Studies in the last 20 years have documented the increased prevalence of knee pain and symptomatic knee OA. Similarly, of temporomandibular joint (TMJ) disorders OA is the most common. Lysyl oxidase like-2 (LOXL2) is a copper-dependent amine oxidase. previous studies showed that LOXL2 is elevated during mouse fracture healing. Our hypothesis that LOXL2 acts as a specific anabolic factor in chondrocytes METHODS: The activity of LOXL2 in human articular and TMJ chondrocytes was assessed by cell-based assays and RT-qPCR, and LOXL2-mediated activation of NF-κB and extracellular signal-related kinase (ERK) signaling pathways was measured by western blotting. To examine LOXL2-induced effect in vivo, we implanted Matrigel-imbedded human chondrocytes into nude mice and exposed them to exogenous LOXL2 for 6 weeks. We also examined if LOXL2 induces the proliferation of OA chondrocytes. RESULTS: LOXL2 staining was detected in damaged regions of human TMJ, hip and knee joints affected by OA. Stimulation with transforming growth factor (TGF)-β1 upregulated LOXL2 expression, while pro-inflammatory cytokines IL-1β and TNF-α downregulated LOXL2, in human chondrocytes. LOXL2 expression also inhibited IL-1β-induced phospho-NF-κB/p65 and TGF-β1-induced ERK1/2 phosphorylation. Matrigel constructs of human chondrocytes from the knee joint and TMJ implanted in nude mice showed anabolic responses after LOXL2 transduction, including increased expression of SOX9, ACAN, and COL2A1. We have found that LOXL2 does not induce the proliferation of human TMJ or knee OA chondrocytes. CONCLUSIONS: We showed that LOXL2 induces differentiation and attenuates OA related catabolic signaling pathways.

The mandibular condyles represent important growth sites within the facial skeleton. Condylar growth is not a pacemaker of mandibular development, but it provides regional adaptive growth that is of considerable clinical significance, as the condyle’s upward and backward growth movement regulates the anteriorly and inferiorly directed displacement of the mandible as a whole. Orthopedic problems of the temporomandibular joint (TMJ), such as displacement of the TMJ disk, are common in the adolescent population. Clinical studies of mandibular asymmetry and mandibular retrognathia in adults as well as in children and adolescents, have reported an association with coexisting non-reducing displacement of the TMJ disk without identifying the cause and effect. Through experimental studies causality has been established, and unilateral affliction during growth has been shown to retard ipsilateral mandibular development with facial asymmetry as the sequel. It was hypothesized that bilateral non-reducing TMJ disk displacement during growth would impair mandibular development bilaterally, resulting in mandibular retrognathia. TMJ disk displacement has repeatedly been demonstrated to induce histological reactions of the condylar cartilage. An additional assumption was therefore that a non-deranged TMJ disk function is crucial for the maintenance of the growing condyle’s biophysical environment, and that a connection ought to exist between the amount of condylar cartilage changes caused by TMJ disk displacement and the amount of subsequent adverse mandibular growth. It was also hypothesized that non-reducing displacement of the TMJ disk in growing individuals would result in qualitative and quantitative changes of the condylar subchondral bone. An improved experimental cephalometric method was developed in order to optimize the reliability of longitudinal radiographic evaluation of fast growing small animals. Bilateral non-reducing TMJ disk displacement was surgically created in ten growing New Zealand White rabbits, with ten additional rabbits serving as a sham operated control group. The amount and direction of craniofacial growth was followed over time in serial cephalograms, aided by tantalum implants in the jaws. The study period was chosen to correspond to childhood and adolescence in man. The assessed growth of each side of the mandible was correlated to the histological feature of ipsilateral condylar cartilage at the end of the growth period. The amount and composition of subchondral bone from three regions of interest in the condyle, and the expression of local growth factors in the adjacent condylar cartilage was evaluated. The results verified that bilateral non-reducing TMJ disk displacement retarded mandibular growth bilaterally; the extent corresponding to mandibular retrognathia in man. Displacement of the TMJ disk during the growth period induced condylar cartilage adaptive reactions that were associated with both an adverse amount and direction of mandibular growth, manifesting in a retrognathic mandibular growth pattern. Growth impairment fluctuated over time, with the most striking retardation occurring during periods of increased general growth, implying a local growth reduction explicitly counteracting general hormonal growth acceleration. A significant decrease of the total amount of subchondral bone, in spite of a general increase of new bone formation in the experimental condyles, pointed to a reparative compensation for an extensive resorption of subchondral bone due to displacement of the TMJ disk, but not to the extent that normal growth would be maintained. These results constitute an explanation for the adverse mandibular development following non-reducing TMJ disk displacement in growing individuals. This project has shown that non-reducing displacement of the TMJ disk during growth has significant consequences on facial development. The findings strongly advocate early and accurate diagnosis and treatment of TMJ disk displacement in the adolescent population, thereby presumably reducing the need for future orthodontic and surgical craniofacial corrective therapy. The results furthermore enhance the need for full appraisal of TMJ disk function in the adolescent population during orthodontic functional therapy, as the condylar cartilage and subchondral bone reactions to a concomitantly displaced non-reducing TMJ disk must be expected to interfere with the intended growth stimulating treatment. The findings of intact articular layers in spite of gross histological and morphological soft and hard tissue changes as a sequel to TMJ disk displacement in growing individuals, implicate a clinical risk of false positive radiographic diagnosis of degenerative changes of the TMJ in children and adolescents.

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Made available in DSpace on 2014-06-11T19:28:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-12-12Bitstream added on 2014-06-13T18:57:54Z : No. of bitstreams: 1 silva_aml_me_guara.pdf: 1372198 bytes, checksum: 8bdab5df0828cfa6c6b83983a359c40b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho tem por objetivos, analisar a intensidade e freqüência dos ruídos articulares da articulação temporomandibular (A.T.M.) de indivíduos saudáveis e patológicos, auxiliar nos procedimentos clínicos e em futuras pesquisas. Para a análise dos sinais coletados foi desenvolvido um sistema para aquisição de dados, composto por um conjunto estetoscópio/microfone, equipamentos para condicionamento e aquisição de sinais e aplicativos computacionais para registro, análise e apresentação dos dados. A identificação das freqüências dominantes e o cálculo dos parâmetros considerados no domínio do tempo (valor médio, valor eficaz, desvio padrão e nível da pressão sonora – NPS) foram realizados por meio de programas computacionais específicos. Os resultados decorrentes dos cálculos e das observações em relação aos sinais obtidos, possibilitaram a determinação das faixas de freqüência, o nível da pressão sonora em decibéis (dB)* da população em estudo, além de proporcionar algumas diferenças entre os grupos patológicos e não-patológicos. Pode-se concluir que a presença da patologia influiu na amplitude dos sinais coletados, diferenciando dessa forma os casos patológicos dos não patológicos. Outra contribuição desse trabalho foi o desenvolvimento de um exame não invasivo para as Disfunções das Articulações Temporomandibulares (D.T.Ms.) / This word has the objective of analyzing the amount and frequency of articular noise in temporomandibular joint (TMJ) of both healthy and pathological individuals and aid in clinical procedures as well as in future researches. For the proposed analysis, a dada collecting system was developed comprising a stethoscope/microphone set, equipment for the signal conditioning and capturing, and computer software for data recording, analysis and presentation. The identification of dominating frequencies and the parameter calculation considered in the time period (average amount, efficient amount, linear fit, and sound pressure level) were performed through specific computer softwares. The results found through the calculations and observations in relation to the signals obtained made the determination of the frequency, the level of sound pressure (in dB) of the studied population possible besides differentiating the pathological and non-pathological groups. It can be concluded that the presence of the pathology influenced in the amplitude of the collected signals, differentiating of this form the pathological cases of the not pathological ones. Another contribution of this work was the development of a not invasive examination for the temporomandibular dysfunction (TMD)

PURPOSE: It has been suggested in some studies that certain malocclusion features are related to Temporomandibular Joint (TMJ) clicking, which is a prevalent sign of Temporomandibular Disorders (TMD’s). This study aimed to evaluate different dental and skeletal malocclusion parameters and their relation to TMJ sounds. Also, to examine TMJ sounds with the presence of headache and TMJ pain using Diagnostic Criteria for Temporomandibular Disorders. MATERIALS & METHODS: A sample of 460 subjects seeking orthodontic treatment were evaluated using DC/TMD. Dental measures were recorded based on the initial records along with the clinical examination of the DC/TMD. Skeletal measurements were recorded after lateral cephalometric radiographs were traced. All measurements were confirmed before collection by one examiner using all the initial records. RESULTS: The sample was comprised of 283 females and 177 males. Clicking prevalence among the sample was 13%, of which 70% were females. Hispanic and Other group were significantly associated with opening and closing TMJ click. Class III dental was highly significant with TMJ click (OR: 0.35). Females who had headache had higher odds of having headache compared to males. Headache was significantly associated with all TMJ click variables (Open click [OR:10], lateral click [OR:10], self-reported click [OR:4.7]). Moreover, TMJ pain was significant with open click (OR:7.6), lateral click (OR:14.4), and self-reported click (OR:7.7). African-American group had 0.28 odds of having TMJ pain compared to Hispanics and Other. Finally, Males have 0.29 odds of having TMJ pain compared to females. CONCLUSION: In conclusion TMJ click upon opening and closing, lateral excursion, and self-reported click is highly associated with headache and chronic headache in general with a prevalence higher in females. Pain was highly associated with TMJ click of all sorts, with a higher prevalence in females and the Hispanic and other group. Finally, TMJ click was found more in the Hispanic and other group and class III dental occlusion subjects.