Temporomandibular joint (TMJ) is one of the most complex joints of the human body. Due to its unique movement, in terms of combination of rotation and translator movement, disc of the joint plays an important role to maintain its normal function. In order to sustain the normal function of the TMJ, disc must be kept in proper position as well as maintain normal shape in all circumstances. Once the disc is not any more in its normal position during function of the joint, disturbance of the joint can be occurred which will lead to subsequent distortion of the disc. Shape of the disc can be influenced by many factors i.e.: abnormal function or composition of the disc itself. Etiology of the internal derangement of the disc remains controversial. Multifactorial theory has been postulated in most of previous manuscripts. Disc is composed of mainly extracellular matrix. Abnormal proportion of collagen type I & III may also leads to joint hypermobility which may be also a predisposing factor of this disorder. Thus it can be recognized as local manifestation of a systemic disorder. Different treatment modalities with from conservative treatment to surgical intervention distinct success rate have been reported. Recently treatment with extracellular matrix injection becomes more and more popular to strengthen the joint itself. Since multifactorial in character, the best solution of the treatment modalities should be aimed to resolve possible etiology from different aspects. Team work may be indication to reach satisfied results.

Background/purposeDysphagia was associated with increased prevalence of aspiration pneumonia (AP) in studies that were criticized for either their small sample size or lack of prospective design. Using a considerably larger nationwide, population-based database and a long-term prospective cohort design, our study aimed to explore the relationship between dysphagia and the subsequent development of AP.Materials and methodsFrom 2000 to 2009, we gathered a study cohort consisting of 6979 newly diagnosed cases of dysphagia from Taiwan's National Health Insurance Research Database. For the control group, another 20,937 individuals without dysphagia were matched for age, sex, and comorbidity. The two cohorts were followed-up to observe the occurrence of AP and correlated mortality.ResultsDuring an average of 3.88 ± 2.73 years of follow-up, we observed 315 cases of new AP [non-dysphagia (193, 0.92%) vs. dysphagia (122, 1.75%), p < 0.0001], and the incidence of AP was significant in the dysphagia group. After adjusting for age, sex, and comorbidity, dysphagia-related AP [hazard ratio (HR) 2.499; 95% confidence interval (CI), 2.089–2.99; p < 0.0001], dysphagia related mortality [HR 3.229; 95% CI, 3.052–3.417; p < 0.0001], and many other systemic diseases were independently associated with a diagnosis of AP.ConclusionDysphagia was highly associated with an increased risk of AP according to data derived from a large nationwide cohort database. Nonetheless, larger prospective studies or meta-analyses are recommended to confirm our findings.

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Background/purpose The pathogenesis of rheumatoid arthritis (RA)-related temporomandibular joint (TMJ) disorder remains unclear. Studies have reported the change of the TMJ after complete Freund's adjuvant (CFA) injection, which is consistent with osteoarthritis. However, few studies have reported that the tissue response of the TMJ in collagen-induced arthritis (CIA) can mimic RA. The present study was aimed to investigate the TMJ response in rat models by CFA-induced arthritis and CIA to verify the proper RA-related TMJ arthritis rat model. Materials and methods In total, 24 rats were randomly divided into four groups: (1) control group; (2) type I collagen injection group; (3) CFA-induced arthritis group; and (4) CIA group. Drugs were injected on Day 0, and the rats were sacrificed on Days 7 and 35. Next, TMJ tissue was collected for hematoxylin and eosin staining, and inflammatory gene ( IL-1β and MMP3 ) expression was investigated. Results Compared with the control group, the type I collagen injection group confirmed the negative inflammatory response through hematoxylin and eosin staining and IL-1βand MMP3 expression. Although CFA-induced arthritis and CIA groups showed inflammatory response (P < 0.05) compared with the control group, histological changes were different. The 7-day CFA-induced arthritis group showed adaptive changes and partly recovered after 35 days of induction. In contrast, 7- and 35-day CIA groups underwent a degenerative process. Conclusion Considering the study limitations, the CIA method is a proper method to study the mechanism of RA-related TMJ arthritis.

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