Application of Subcritical Water Hydrolysate from Thermosetting Polyester Resin to Aqueous Agents

Thermosetting polyester resin used in fiber reinforced plastic (FRP) is very difficult to be recycled since it cannot be re-molded like thermoplastic resin. In recycling thermosetting polyester resin, subcritical water with alkali was applied to hydrolyze ester bonds to obtain styrene-fumaric acid copolymer (SFC). SFC, subcritical water hydrolysate from thermosetting polyester resin, has a molecular structure of functional polymer. Alkali salt of the SFC has a same molecular structure as alkali salt of styrene-maleic anhydride copolymer (SMA) which is widely used in various kinds of high performance additives for aqueous applications. In these applications, dispersing agent, detergent builder, and surface sizing agent were selected for application of alkali salt of the SFC . The reaction product liquid contains sodium salt of SFC (SFC-Na). It was evaluated as dispersing agent and detergent builder. Ammonium salt of SFC (SFC-NH4) was evaluated as surface sizing agent for paper. The evaluation results were compared with that of commercial additives to verify the possibility to substitute them. The reaction product liquid showed superior dispersing effect to commercial dispersing agent for hydrophobic powder. It also showed superior alkali buffering capacity to commercial detergent builder. SFC-NH4 showed higher sizing effect than commercial sizing agent

シュキノウ ブイ ト ホテツ チリョウ

Mastication is an essential function for processing foods into a bolus in the oral cavity. This behaviour is thought to be controlled by a central pattern generator in the brain stem and to be influenced by the morphological properties and the texture of foods. The 'main occluding area', the location where food crushing occurs during the first stroke of mastication, is reported to be an important concept; however, it is currently limited to findings in individuals with normal dentition. We assessed changes in the location, area, and bite force of the main occluding area before and after implant treatments. The main occluding area was located at a reproducible location in the partially edentulous and normally dentate subjects. This location was principally the first molar region, and for the partially edentulous patients with missing teeth in the molar regions, it moved from the premolar region to the first molar region after treatment. These results suggest that the main occluding area can be restored to the first molar region after implant treatment and may be an important factor in the assessment of prosthodontic treatment. The main occluding area is very simple to identify using a dental stopping and has the potential to become a useful addition in the assessment of prosthodontic treatment and mastication. This article describes outlines the main occluding area and our latest findings

Cascade between oral function and physical frailty

Background: No report has yet examined the impact of oral hypofunction on physical frailty in relation to intra‐relationships of physical frailty assessment items. The purpose of this study was to verify the potential of a clinical cascade between oral hypofunction and physical frailty, and especially to support the hypothesis that the influence of oral hypofunction on physical frailty is greater than the intra‐relationships among elements of physical frailty, and that sex differences significantly affect these relationships. Methods: The participants were 272 older adults (101 men and 171 women; mean age 75.1 ± 7.5 years). Maximum occlusal force (MOF) and oral dryness (OD), as indicators of oral hypofunction, and grip strength (GS) and walking speed (WS), as indicators of physical frailty, were measured. Mutual relationship of four variables was verified using covariance structure analysis. Results: In men, three paths from MOF to WS and GS and from WS to GS were confirmed, and those from MOF to WS and from WS to GS were found to be significant (p < 0.01). In women, three paths from MOF to WS and GS and from WS to GS were also confirmed, as with the men, and those from MOF to WS and from MOF to GS were found to be significant (p < 0.01). Model adaptability was shown to be good for both men and women. Conclusion: The results suggest our hypothesis was verified, and it is expected that the early detection of oral hypofunction, that is, MOF, may be important for assessing physical frailty, especially in women

求心性の歯周組織感覚入力により誘発された前頭前野の活動は咬合力を抑制する

The prefrontal cortex (PFC) plays an important role in several cognitive functions, such as planning, decision making, and social behavior. We previously reported that periodontal sensory input significantly increases PFC activity during the motor task of maintaining occlusal (biting) force. However, the relationships between periodontal sensation, PFC activity, and the performance of motor tasks, have not been evaluated in detail. Therefore, using functional near-infrared spectroscopy, we investigated PFC activity by monitoring changes in cerebral blood flow (CBF) to specific areas of the PFC that corresponded to changes in occlusal force generated during 4 different biting tasks: 1) occlusion with the central incisor with an interocclusal distance of 5 mm (BI-5 mm); or 2) 10 mm (BI-10 mm); 3) occlusion with the first molars with an interocclusal distance of 5 mm (BM-5 mm), or 4) 10 mm (BM-10 mm). Occlusion of molars generated increased PFC regional CBF as the interocclusal distance decreased (BM-10 mm vs BM-5 mm). No significant differences in CBF during occlusion of incisors were found when comparing 5 mm and 10 mm intercostal distances (BI-5 mm vs BI-10 mm). The mean occlusal force generated by BM-5 mm occlusion was significantly lower than that generated by BM-10 mm occlusion. Taken together, our results suggest that the PFC decreases efferent signaling to motor units, to reduce occlusal force generated when periodontal sensation, which is greater when the interocclusal distance is reduced, is primarily responsible for maintaining occlusal force in the absence of sensations from the temporomandibular joint and muscle spindles

Investigating Eating Behaviors and Symptoms of Oral Frailty Using Questionnaires

A questionnaire survey was conducted to investigate eating behavior and the subjective symptoms of oral frailty, and to examine the relationship between them. A total of 744 subjects with ages over 65 years were included. The questionnaire comprised 18 question items indicating eating behavior and seven question items indicating oral frailty. All items were assessed according to 4 grades on a scale of 1 (not applicable) to 4 (applicable). The total score of oral frailty gradually increased with age. Regarding the scores for “eating recognition” and “eating habits”, no changes were observed, however the scores for “eating action” demonstrated a decreasing tendency with age and the scores of ≥ 85 years age group was significantly lower than the 65–69, 70–74, and 75–79 years age groups. As a result of multiple regression analysis, among the significant independent variable, the scores of “I do not chew foods well” under the category of “eating action” showed the highest standard partial regression coefficients for dependent variable of symptoms of oral frailty. The significant association was found between the eating behavior and subjective symptoms of oral frailty, and this study suggests that the good chewing habit might be an important criterion for the prevention of oral frailty

Did “Kayoinoba” Prevent the Decline of Mental and Physical Functions and Frailty for the Home-Based Elderly during the COVID-19 Pandemic?

The purpose of this study is to grasp the management situation of “Kayoinoba” under the conditions of self-quarantine due to the COVID-19 pandemic. It is also to clarify the efficacy of “Kayoinoba” using the Kihon Checklist (KCL) for the assessment of mental and physical functions in the elderly. The respondents were 136 elderly people aged 65 years and over who lived in A City, a standard rural area in Japan. The age, gender, living style, affluence for living, and the frequency of participation in “Kayoinoba” were examined by using the KCL as a self-completed questionnaire. Finally, 101 respondents were included in the final analysis. There was no difference in the participation status before and after the spread of COVID-19. The frailty ratio tended to decrease from 23.8% to 19.8% between the two periods, but there was no difference in the frailty ratio. It is suggested that the participants in “Kayoinoba” may have suppressed the deterioration of mental and physical conditions, excluding physical activity. This would prevent the frailty of the elderly, even during self-quarantine due to the spread of COVID-19

Acute inflammatory response to contrast agent aspiration and its mechanisms in the rat lung.

Objectives/hypothesisContrast agent (CA) aspiration is an established complication of upper gastrointestinal and videofluoroscopic swallow studies. The underlying molecular biological mechanisms of acute response to CA aspiration in the respiratory organs remain unclear. The aims of this study were to elucidate the histological and biological influences of three kinds of CAs on the lung and to clarify the differences in acute responses.Study designAnimal model.MethodsEight-week-old male Sprague Dawley rats were divided into five groups (n = 6 in each group). Three groups underwent tracheal instillation of one of three different CAs: barium (Ba) sulfate, nonionic contrast agents (NICAs), and ionic contrast agents (ICAs). A control group was instilled with saline and a sham group was instilled with air. All animals were euthanized on day 2 after treatment and histological and gene analysis was performed.ResultsNo animal died after CA or control/sham aspiration. Ba caused severe histopathologic changes and more prominent inflammatory cell infiltration in the lungs compared with the two other iodinated contrast agents. Increases in expressions of inflammatory cytokines (tumor necrosis factor [Tnf], interleukin-1β [Il1b], and interferon-γ [Ifng]) were observed in Ba aspiration rats, and upregulation of Il1b was seen in ICA aspiration rats. NICA did not cause obvious histologic changes or expressions of inflammatory cytokines and fibrosis-related genes in the lungs.ConclusionsBa caused significantly more acute lung inflammation in a rodent model than did ioinic and nonionic iodinated CAs. Nonionic contrast did not cause any discernible inflammatory response in the lungs, suggesting that it may be the safest contrast for videofluoroscopic swallow studies.Level of evidenceNA Laryngoscope, 129:1533-1538, 2019

Application of artificial intelligence in the dental field : A literature review

Purpose: The purpose of this study was to comprehensively review the literature regarding the application of artificial intelligence (AI) in the dental field, focusing on the evaluation criteria and architecture types. Study selection: Electronic databases (PubMed, Cochrane Library, Scopus) were searched. Full-text articles describing the clinical application of AI for the detection, diagnosis, and treatment of lesions and the AI method/architecture were included. Results: The primary search presented 422 studies from 1996 to 2019, and 58 studies were finally selected. Regarding the year of publication, the oldest study, which was reported in 1996, focused on “oral and maxillofacial surgery.” Machine-learning architectures were employed in the selected studies, while approximately half of them (29/58) employed neural networks. Regarding the evaluation criteria, eight studies compared the results obtained by AI with the diagnoses formulated by dentists, while several studies compared two or more architectures in terms of performance. The following parameters were employed for evaluating the AI performance: accuracy, sensitivity, specificity, mean absolute error, root mean squared error, and area under the receiver operating characteristic curve. Conclusion: Application of AI in the dental field has progressed; however, the criteria for evaluating the efficacy of AI have not been clarified. It is necessary to obtain better quality data for machine learning to achieve the effective diagnosis of lesions and suitable treatment planning

Does Periodontal Tactile Input Uniquely Increase Cerebral Blood Flow in the Prefrontal Cortex?

We previously studied the effect of peripheral sensory information from sensory periodontal ligament receptors on prefrontal cortex (PFC) activity. In the dental field, an alternative dental implant without periodontal sensation can be applied for missing teeth. In this study, we examine whether periodontal tactile input could increase cerebral blood flow (CBF) in the PFC against elderly patients with dental implants lacking periodontal tactile (implant group), elderly individuals with natural teeth (elderly group), and young individuals with natural teeth (young group). The experimental task of maintaining occlusal force as closed-loop stimulation was performed. Compared with the young group, the elderly group showed significantly lower CBF. Contrastingly, compared with the young group, the implant group showed significantly lower CBF. There were no significant differences between the elderly and implant groups. Regarding the mean occlusal force value, compared with the young group and the elderly group, the implant group had a numerically, but not significantly, larger occlusal force exceeding the directed range. In conclusion, the periodontal tactile input does not uniquely increase PFC activity. However, increased CBF in the PFC due to the periodontal tactile input in the posterior region requires existing attention behavior function in the PFC