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Get PDFRoutine oral hygiene is important for the control of opportunistic pathogens in the oral cavity of institutionalized elderly individuals. We evaluated the effects of routine oral care on opportunistic pathogens at various time points after admission to a nursing home. Twenty-five elderly subjects living in the nursing home (mean age: 86.0±10.4 years) participated in the study. Caregivers and dental hygienists cleaned the teeth, dentures, tongue, and mucosa after each meal using both routine and professional oral care techniques. Opportunistic pathogens were collected from the teeth, tongue, and mucosal surfaces using a cotton swab; and the species of microbes were determined and the numbers were counted following cultivation on selective agar. Regular oral care including professional oral care was found to be effective for reducing infections by many kinds of opportunistic pathogens on the teeth surfaces and the oral environment without food residue during a long-term study (6 months). Further, this care after 1 month significantly reduced infections by opportunistic pathogens on mucosal surfaces in subjects without dentures; however, this was not observed in those with dentures. Our data shows the importance of regular oral care in cleaning hard and soft surfaces of the oral cavity improves the oral health of the institutionalized elderly.departmental bulletin pape
Get PDFNeural progenitor cells (NPCs) and bone marrow stromal cells (BMSCs), both of which can differentiate into neural phenotypes, are important candidates for transplantation therapy in the central nervous system (CNS). In most cases of BMSC transplantation, functional recovery is recognized even if few transplanted cells survive in the host tissue. A reason for this may be that transplanted cells produce neurotrophic factors (NFs), which enhance neuronal survival and neurite outgrowth after CNS injury. To provide additional insight into cell therapy, we investigated the types of NFs and receptors that are expressed in NPCs and BMSCs in vitro. Both cells expressed the mRNA of nerve growth factor (NGF), cilliary neurotrophic factor (CNTF), glial cell line-derived neurotrophic factor (GDNF), and their receptors in the proliferative state. Real-time PCR analysis showed that mRNA expression of GDNF was relatively low in NPCs although its receptor was highly expressed. We thus tested if the overexpression of GDNF in NPCs affected neural differentiation without FGF-2. The overexpression of GDNF did not affect mRNA expression of β-III tubulin and neuron specific enolase (NSE), but both GDNF and GFRα1 overexpression increased the expression of neuronal markers. These results suggest that augmentation of both GDNF and GFRα1 could have positive effects during neural tissue repair.departmental bulletin pape
Get PDFRecently, improvement of the properties of dentin surface using dental lasers to increase bonding strength has been anticipated in the field of adhesive dentistry. The objective of this study was to investigate changes in the surface properties of human dentin after ArF excimer laser irradiationat different irradiation times, pulse repetition rates and energy densities. The SEM images of the irradiated surfaces were observed, and the contact angle and the roughness of the irradiated surface were measured. As a result, SEM demonstrated that the dentin surface became irregular following ArF excimer laser irradiation. When the energy density increased, the irregularity became more minute and dentinal tubules were more easily identified. By contrast, such changes were not observed when the irradiation time and pulse repetition rate were changed. Moreover, as energy densities increased, the contact angle tended to decrease and the surface roughness tended to increase. These results suggested that the area of the irradiated surface and wettability increased after irradiation with the ArF excimer laser. Consequently, irradiation with ArF excimer lasers could improve the surface properties and be potentially useful for adhesive dentistry.departmental bulletin pape
Get PDFAcrylic bone cement is self-curing cement comprising of liquid and powder component of methyl methacrylate (MMA). It has been used extensively in orthopedics; however, adverse effects were associated with its use. Hence we investigated in this paper the possibility of new cement utilizing methacrylates with lower toxicity than MMA. LD50s of candidate monomers were determined with administration to the medullary cavity of the rat's femur. 2-Ethylhexyl methacrylate (EHMA) and trimethylolpropane trimethacrylate (TMP) demonstrated greater LD50 values of 187 mg/kg and 380mg/kg, respectively, than MMA (108 mg/kg); they were selected as the liquid components of the new cement. The copolymer of EHMA and cyclohexyl methacrylate was then selected as the powder component. With this combination, we developed the new cement (EHMA cement). Temperature rise during polymerization of EHMA cement was 9°C–13°C, which was significantly lower than that of conventional cement. The compression strength of the polymerized EHMA cement was 57 MPa without TMP, and 67 MPa with TMP (15 wt%). Thus we concluded that new EHMA cement was slightly inferior in the compression strength than the conventional cement. However, it was characterized by the low toxicity of utilized monomers and the low temperature rise during polymerization.departmental bulletin pape
Get PDFTissue-nonspecific alkaline phosphatase (TNSALP) and Ca-ATPase are known to play roles in bone mineralization, but how these enzymes contribute to appositional mineralization has been illusive. Here we examined the active sites of these enzymes in appositional mineralization using the bones of young rats being administered with 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) for 5 days. The doses of HEBP totally abolished mineralization of newly formed bone matrix except in matrix vesicles (MVs), and hence allowed precise localization of MVs and phosphatase reactions within non-mineralized extracellular matrix. Intense TNSALP and ATPase reactions were confirmed along the limited portions of osteoblast membranes where intimate cell-cell contacts were maintained. Diffuse reactions of these enzymes were throughout the osteoid implicating efflux of TNSALP and ATPase molecules into extracellular matrix from the osteoblast membranes. Phosphatase reactions associated with MVs varied both in intensity and location among the individual vesicles; newly formed MVs were almost free of reactions but appeared to gain those activities later in the osteoid. These data suggest that TNSALP and ATPase are released from the osteoblast membrane and later integrated into MVs within the osteoid. The osteoblasts may thus regulate appositional mineralization of bone from a distance at least in part by providing phosphatases via MVs.departmental bulletin pape
Get PDFOcclusal stimuli and the periodontal healing of replanted teeth have been reported to be related. However, the mechanism for preventing dentoalveolar ankylosis remains unclear. Basic fibroblast growth factor (bFGF/FGF-2) is considered as a key factor in wound healing. The purpose of this study was to evaluate the relationship between occlusal stimuli, bFGF, and the periodontal healing after tooth replantation. Five-week-old male rats were divided into non-occluded, occluded, and recovery groups. The right maxillary first molars were replanted in all groups, and the left maxillary first molars in the 2-week occluded group without replantation were served as nontreated. An anterior bite plate was attached to the maxillary and mandibular incisors to produce occlusal hypofunction in the non-occluded group and was then removed after 1 week in the recovery group. Histological observations were performed after 1 and 2 weeks of the experimental period. After 2 weeks, the non-occluded group had detectable ankylosis and obvious periodontal tissue stricture. Meanwhile, the occluded and recovery groups showed enlarged and thickened periodontia without ankylosis. The number of bFGF-positive cells in the occluded and recovery groups significantly increased as compared to in the non-occluded group. These results suggest that occlusal stimuli enhance the production ofbFGF in the periodontal healing of replanted teeth and prevent dentoalveolar ankylosis.departmental bulletin pape
Get PDFThe aim of this study was to investigate changing mechanical properties of the bolus during mastication and to quantify mechanical properties of the final bolus at swallowing. Changing mechanical properties of the bolus of three different types of foods (rice cracker, cheese and peanuts) by twelve normal dentitions were investigated by principal component analysis (PCA) on six mechanical properties (rupture energy, elasticity, viscosity, hardness, cohesiveness and adhesiveness). The raw data of cohesiveness immediately before swallowing was always constant. In all three food samples, the results by PCA on six parameters indicated that cohesiveness was independent from the remaining five parameters, and two factors were extracted on these five parameters by PCA. Furthermore, factor structure of bolus at swallowing showed no difference between the three food samples in spite of the variations in the raw data. The mechanical properties of swallowable bolus were clarified for the first time.departmental bulletin pape
Get PDFThe national survey on health and welfare conducted in 1999 reported approximately 15% of people, who had some dental problem, suffered from oral malodor. Oral malodor was ranked the fourth highest dental complaints in Japanese. However, there is a scarcity of epidemiological studies assessing the prevalence of oral malodor in the general population. Thus the aims of this study were to assess the prevalence of oral malodor and its relationship with oral health indicators among general adults aged 40 to 75 years in Akita Prefecture, Japan. The prevalence of oral malodor, diagnosed using the organoleptic method, revealed that approximately 37% of subjects had oral malodor. Logistic regression analysis suggested that oral hygiene, periodontal disease and oral dryness were influential factors which could cause oral malodor. Hence oral malodor related health education, preventive interventions such as tooth and tongue brushing instruction, and treatment regimens targeting periodontal disease should be incorporated into community oral health programs. Such an approach would bring about not only a reduction in the complaint of oral malodor condition, but also the promotion of overall oral health.departmental bulletin pape
Get PDFWe studied the effect of cigarette smoke extract (CSE) on a three-dimensional (3-D) co-culture model with epithelial cells and mesenchymal cells to clarify how epithelial cells protect lung tissue from cigarette smoke in-vivo. Two types of gels were prepared. The one was the co-culture of human fetal lung fibroblasts (HFL-I) embedded in type-I collagen gel, with alveolar epithelial cells (A549) cultured covering the top of the gel. The other was HFL-I cells alone. After 48 hours from CSE exposure, gel contraction, levels of fibronectin, transforming growth factor(TGF)--β1 and GSH were assessed. CSE inhibited fibroblast-mediated gel contraction and this inhibition was lessened in co-culture associated with higher GSH concentration and TGF-β1 level as compared to the level in HFL-I cells alone. CSE lowered fibronectin level to a lesser extent in co-culture as compared to the level in HFL-I cells alone. Exogenous TGF-β1 restored the inhibition of gel contraction by CSE independent of GSH level. Cigarette smoke may interfere with 3-D co-culture gel contraction by diminishing GSH, fibronectin and TGF-β1 action in the epithelial-mesenchymal interaction.departmental bulletin pape
Get PDFThe purpose of this in vitro study was to investigate the effect of hardness on the reduction of stress transferred to tissues around implants using a resilient material applied to the female parts of the ball attachment in maxillary implant overdentures. A cast chrome-cobalt framework was mounted onto a maxillary acrylic edentulous model, which contained two implants and four strain gauges attached to the implant. Ball abutments were screwed into the implant. One abutment was connected to a dedicated metal cap embedded in the housing, while the others were connected to resilient test materials with four different hardnesses. Loads were applied using a universal testing machine with a magnitude of 50 N. The sums of the absolute values recorded from the four strain gauges were used for stress evaluation. The measured strains were analyzed statistically using two-way ANOVA and multiple comparisons. A resilient material with hardness 90 exhibited strains that did not differ significantly from the control. In contrast, the other resilient materials showed significantly reduced strains under all conditions. In this limited study, application of resilient silicone materials with approximate hardness 80 to the female parts of ball attachments significantly reduced the stress on the tissues around the implant.departmental bulletin pape