Fibronectin is a component of the extracellular matrix in the synovium. Fibronectin fragments（FN-fragments）result from fibronectin breakdown by proteolytic enzymes released from an early inflammatory response. We examined the effect of a 120-kDa fibronectin fragment（120-kDa FN-fragment）in the inflammatory condition of temporomandibular joint（TMJ）synovitis. Fibroblast-like synoviocytes, which were isolated from the TMJ synovium using the outgrowth method, were treated with or without 120-kDa FN-fragment. The fibronectin fragment induced the expression of monocyte chemotactic protein（MCP）-1, -2, and -3 genes in fibroblast-like synoviocytes as seen with DNA microarray analysis and real-time PCR. Among 120-kDa FN-fragment response genes, MCP-1（also called CCL2）, which is the main MCP chemokine, was abundantly expressed. MCP-1 protein level was increased in the conditioned medium with fibroblast-like synoviocytes treated with 120-kDa FN-fragment using ELISA. Furthermore, experiments using inhibitors of signaling pathway revealed that 120-kDa FN-fragment up-regulated MCP-1 expression as a result of NF-κB activation. MCP-1 mainly induces monocyte/macrophage migration in inflammation caused by various diseases. These results suggest that production of the MCP chemokine by 120-kDa FN-fragment may be involved in promoting the inflammatory condition of TMJ.

We previously reported that oral inoculation of the oral commensal bacteria Fusobacterium nucleatum（F. nucleatum）induced periodontitis and disrupts the intestinal im mune response. However, the effect of the intestinal microfloral balance, inflammation of the intestinal tract, and the mechanism of periodontitis induction by F. nucleatum was unknown. Therefore, in this study, we examined the mechanism of colitis caused by oral inoculation with F. nucleatum. Mice were orally inoculated with F. nucleatum 5 times a week for 3 weeks and sacrificed either at day 1 or day 30 after their last oral inoculation. Feces, large intestine and blood were collected and used for enterobacterial, immunological, and histological analyses. The number of Clostridium spp. in the intestinal microbiome and the amount of IgA antibodies in the feces were significantly reduced. F. nucleatum was detected in the feces and serum on day 1 and in the large intestine and serum on day 30 after the last oral inoculation. The number of M1 macrophages was significantly higher in the F. nucleatum-challenged group. The gene expression and protein productions of IL-1β and IL-18 were significantly higher in the large intestine at day 30. Additionally, the expression of NLRP3 and GSDMD were also significantly elevated on day 30. Caspase-1 showed an increasing trend in both gene expression and protein production. However, Caspase-11 was significantly increased at the protein level, which persisted until day 30. These results suggested that Caspase-11 contributed to the induction of inflammation in the large intestine after F. nucleatum inoculation.

This study aimed to evaluate the effect of CT values of the tooth root and bone on root resorption using data obtained before and after orthodontic treatment. Forty-one patients with jaw deformities were divided into those with and without root resorption （n = 18 and 23, respectively）. The distance from the anatomical root apex to the edge of the incisive canal was measured using axial CT sections before active treatment. The distance from the anatomical root apex to the labial and palatal cortical bone and the CT values of the root and alveolar bone were measured and compared using sagittal CT sections. The tooth axis and vertical and lateral movements of the maxillary right central incisor were examined using lateral cephalograms before and after treatment. Root resorption group showed significantly higher CT values of alveolar bone than the control group and different axial movement of the root apex and distance between the labial cortical bone and root apex on lateral cephalograms. The risk of root resorption increased with an increase in the CT values of the alveolar bone surrounding the maxillary central incisor. The horizontal movement of the root apex was associated with the distance between the labial cortical bone and root apex, and root resorption during maxillary central incisor movement.

This study was performed to evaluate the association of jaw and neck muscle coordination with jaw movement activity in order to clarify the relationships of electromyogram（EMG）-EMG findings showing coherence between jaw and neck muscle activities and jaw movement activities while chewing in healthy individuals. Sixteen subjects performed gum chewing, with EMG signals in the jaw and neck muscles and jaw movements were simultaneously recorded. Coherence between jaw and neck muscle activities and jaw movements while chewing, as well as first peak frequency of the power spectrum, was analyzed while left and right side chewing using EMG-EMG coherence function analysis. Those results were used to evaluate the relationship of jaw and neck muscle activities with jaw movements while rhythmical chewing. The results suggest a positive correlation between jaw and neck muscle activity coherence and jaw opening activities while chewing, which was especially evident in non-chewing side neck muscle recordings. Considering findings of previous qualitative evaluation suggested coordinated jaw and head movement activities and enlarged jaw opening activity induced by large-food chewing, present study may suggest the association of quantitative synchrony between jaw closing and non-chewing side neck muscle activities with jaw opening activity while chewing performance in healthy individuals.

To determine the status of outpatients at the Dental Hospital of Nihon University School of Dentistry at Matsudo, we surveyed new patients examined in the Department of Operative Dentistry between April 1, 2019 and March 31, 2020. The following six items were extracted from the patients’ electronic dental records: referral（yes/no）, sex, age, residence, chief complaint, and site of chief complaint. Patients were subsequently divided into groups according to referral status for comparison of the other items. To identify factors associated with referrals, we performed logistic regression analysis with referral as the dependent variable and sex, address, age, chief complaint, and site as independent variables; odds ratios and 95% confidence intervals were calculated for each variable. Odds ratios were high for age, site, chief complaint, and sex and yielded the following conclusions concerning these variables. Regarding age, most patients in the referral group were in their 40s and 50s, while most patients in the non-referral group were in their 60s and 70s. The majority of new patients were female, while the percentage of male patients was slightly higher in the referral group than in the non-referral group. The most common sites were the molars in both groups. The most common chief complaints in the referral group and the non-referral group were apical periodontitis and class 2 caries, respectively. These results suggested that compared with the non-referral group, patients in the referral group were younger, were diagnosed earlier, and visited our hospital with greater expectation of dental preservation through high-quality treatment.

A decrease in oral function is a risk factor for aspiration pneumonia and suffocation, leading to a reduction in physical function and malnutrition at elderly people.. Therefore, there is a need to develop a simple method to improve oral function in older adults, including those requiring long-term care. This study aimed to elucidate the effects of chewing gum mastication training and habitation on the oral environment, eating habits of residents and users of the elderly facility. Subjects were randomly assigned to two groups, the intervention and control groups. The intervention group consisted of 28 subjects（80.0［74.0-87.0］years）who chewed gum for 2 minutes three times daily for 2 months and the control group consisted of 26 subjects（88.0［82.5-94.0］years. Oral examination, oral function, physical condition, dietary habits questionnaire, and caregiver’s Vitality Index（VI）were evaluated. As a result, intra-group comparisons before, during, and after the intervention showed significant differences in gum mastication ability（p = 0.004）, appetite related to diet（p = 0.026）, looking forward to eating（p = 0.011）, and VI（p = 0.047）in the gum mastication group. In addition, gum mastication ability（p = 0.018）and appetite（p = 0.003）marked significant differences in changes before and after the intervention for the two groups. Furthermore, logistic regression analysis also revealed the impact of the intervention by gum mastication. It was shown that the simple intervention of chewing gum mastication used here might lead to improved oral function, increased interest of the elderly in diet and food, and increased motivation.

We have previously reported that oral inoculation with Fusobacterium nucleatum（F. nucleatum）caused horizontal bone resorption and increases the RANKL/OPG ratio. However, the mechanism of periodontitis induction by F. nucleatum was unknown. This study investigated how oral inoculation with F. nucleatum induced periodontitis. Mice were inoculated orally with F. nucleatum 5 times a week for 3 weeks. At day 1 or day 30 after the last oral inoculation, the animals were euthanized and subjected to histological and immunological analyses. Significant alveolar bone resorption with osteoclasts was observed in the F. nucleatum inoculation group. Inflammatory cytokines were significantly increased in gene and protein assay at day 30 after the last oral inoculation. Interestingly, F. nucleatum was detected in the serum at day 30 but not in the gingival tissue. These findings suggested that gingival inflammation might be induced via the bloodstream. Therefore, when Ca9-22 cells were added serum from F. nucleatum-inoculated mice, IL-1β was significantly observed, which was confirmed by gene and protein assays. These results suggested that F. nucleatum in blood played a central role in periodontitis caused by oral inoculation of F. nucleatum. In addition, systemic circulation of F. nucleatum was likely to contribute not only to periodontitis but also to the pathogenesis of remote organs.

Rapid maxillary expansion（RME）is a technique used to treat dental malalignment. Consensus has yet to be reached changes in the epipharyngeal region associated with RME. The objective of this study was to ascertain the morphological changes that occur in the epipharyngeal region as a result of RME. In the present study, a comparative investigation of the pharyngeal tonsils and the epipharyngeal airway on lateral cephalograms scanned before and after RME was therefore performed. Fourteen patients who underwent orthodontic treatment for dental malalignment by RME were included. The mean length of pharyngeal tonsil（A）was 114.65 pixels before RME and 108.64 pixels after RME. The mean value of epipharyngeal space（N）was 210.72 pixels before RME and 233.95 pixels after RME. The mean A/N ratio was 0.547 before RME and 0.466 after RME. The mean pharyngeal tonsil（Pt）area was 16181.14 pixels before RME and 16407.71 pixels after RME. The mean airway（Air）area was 12488.96 pixels before RME and 16040.64 pixels after RME. The mean Pt / Ep（Ep = Pt + Air）area was 0.570 before RME and 0.502 after RME. In this study showed that the A/N and Pt/Ep ratios decreased significantly after RME. The N and Air area values also increased significantly, but there were no significant changes in the A and Pt area values. It was concluded that the decrease in the A/N and Pt/Ep ratios were due to the changes in the N and Air area values.