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Human cellular cementum has incremental lines that demarcate individual cementum lamellae. The structural and functional details of the lines remain poorly understood. This study was designed to examine human cellular cementum using light microscopy, scanning electron microscopy, and contact microradiography and to elucidate the ultrastructure of incremental lines and their significance in cellular cementogenesis.Longitudinal paraffin and ground sections of human mandibular molars were prepared. Paraffin sections were stained with hematoxylin, or hematoxylin and eosin, or impregnated with silver. Hematoxylin-stained sections were observed via scanning electron microscopy using NaOH maceration. Silver-impregnated sections were further stained with hematoxylin. Hematoxylin-stained ground sections were examined using contact microradiography.The incremental lines were found to be collagen fibril-poor layers. The outer area of each cementum lamella consisted of highly mineralized fibrils involved in constructing an alternating lamellar structure, whereas the inner area consisted of irregularly arranged, less highly mineralized, fibrils. The incremental lines corresponded with the innermost sites of the inner area.Based on the obtained findings, we suggest that cellular cementogenesis progresses as follows. (1) Cementoblasts alternate between low-to high-activity states. (2) In the earliest low-activity stage, cementoblasts generate poorly mineralized, fibril-poor, incremental lines. (3) As cementoblasts recover activity, fibril-organization and mineralization advance in the cementum. (4) In the high-activity stage, cementoblasts reach full activity and construct the highly mineralized, alternating lamellar structure. (5) Cementoblasts revert back to the low-activity stage. (6) The above processes are repeated, thus, alternately generating the incremental lines and cementum lamellae.

We present a case of 6-year- and 10-month-old boy with an impacted primary molar. An x-ray photograph revealed the impacted mandibular right primary second molar with small hard tissue on the crown of the tooth as an obstacle. We extracted the small hard tissue and the mandibular right primary second molar. A histopathological examination of the obstacle revealed a tooth germ containing dental papilla, dentin, and enamel. The obstacle was diagnosed as the tooth germ of the mandibular right second premolar. In conclusion, the early detection of impacted primary molars is important for children's healthy growth and development. (C) 2022 The Authors. Published by Elsevier Ltd on behalf of Japanese Society of Pediatric Dentistry.

This study examined the effects of N-acetylcysteine (NAC) on the inflammatory reactions of murine osteoblastic cells cultured on the 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate (4-META/MMA)-based resin. Superbond CB however, they were suppressed by NAC. Furthermore, PGE2 production in the culture medium was increased in SB, whereas NAC decreased the PGE2 production. NAC lowered the ROS level in the culture medium and significantly increased the intracellular GSH level. The present in vitro study demonstrated that NAC might be effective for dental material detoxification.

In the case of complete luxation with dental trauma, delayed replantation leads to a higher probability of root resorption. We evaluated the efficacy of N-acetylcysteine (NAC) as a root canal medication for trauma-associated root resorption. A rat dental trauma model was used. In the test group, mesial root pulpectomy was carried out after tooth extraction. NAC was applied as a root canal medication followed by replantation. We euthanized the rats after two weeks, excised the maxilla, and prepared thin sections, followed by H-E and TRAP staining. Furthermore, RAW264.7 cells were treated with RANKL and NAC. The effects of NAC on osteoclast differentiation were investigated by determining the numbers of osteoclasts and nuclei and quantifying osteoclast-related mRNA expression levels by real-time PCR. The level of root resorption and number of odontoclasts tended to be lower in the NAC groups than in the control group. In terms of osteoclast differentiation, the total number of osteoclasts was lower in both the 5 and 10 mmol/L NAC groups than in the control group. Real-time PCR revealed that the expression levels of RANK, NFATc1, DC-STAMP, CD47, and cathepsin K were lower in the 10 mmol/L NAC group. NAC tended to inhibit root resorption and reduce the number of odontoclasts. NAC also inhibited the expression of osteoclast-related genes. Overall, NAC reduced the number of odontoclasts, inhibited bone resorption, and influenced the inhibition of osteoclast differentiation, fusion, and functions. Therefore, we suggest that NAC may be beneficial in the treatment of root resorption. (C) 2020 Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All rights reserved.

Microtubules of the eukaryotic cytoskeleton are involved in critical cellular processes, including mitosis, cell motility, and intracellular transport. They are assembled from tubulin heterodimers that contain different α-tubulin (TUBA) and β-tubulin (TUBB) isotypes. Among these isotypes, Class III β-tubulin (TUBB3) is highly expressed in the brain and testes, and aberrant expression has been reported in a multitude of human cancer types. In this study, we investigated TUBB3 expression in the developing mouse teeth using immunohistochemistry. Similar to previous research, immunohistochemistry with TUBB3-specific antibodies showed immunoreactivity in the nerve fiber around the tooth germ. However, TUBB3 immunoreactivity was minimal or not seen at all in the tooth germ at early cytological and histological differentiation stages of developing teeth. However, the immunoreactivity was intense in odontoblasts during dentin formation and in most ameloblasts at the secretory stage. Intense immunoreactivity was observed only in some ameloblasts at the maturation stage. Similar to the immunoreactivity in ameloblasts and odontoblasts, the immunoreactivity was intense in cementoblasts during cementum formation. The spaciotemporal profiles of TUBB3 expression suggested that TUBB3 may be correlated to some cellular process at the mineralization stage of tooth development.

Stem cells from human exfoliated deciduous teeth (SHED) are mesenchymal stem cells with multipotent differentiation potential present in the dental pulp tissue of the deciduous teeth. SHED produce secretions that have immunomodulatory and regenerative functions. In the present study, we investigated the effects of SHED-conditioned medium (SHED-CM) on osteopenia induced by the ovariectomy (OVX) phenotype and its corresponding immunological changes. Eleven-week-old female C3H/HeJ mice were subjected to OVX. SHED-CM was administered intraperitoneally in these mice for 4 weeks starting immediately after OVX. SHED-CM improved bone mass after OVX and elevated the polarization of M2 macrophages in the peritoneal cavity. SHED-CM also suppressed an OVX-induced increase in interferon-γ (INF-γ) and interleukin-17 (IL-17) concentrations in the peripheral blood. Inhibition of M2 macrophage polarization with neutralizing antibodies did not reduce the concentration of IFN-γ and IL-17 in peripheral blood, which were increased by OVX, and did not alleviate osteopenia induced by the OVX phenotype. Mechanistically, these findings suggest that SHED-CM alleviates bone resorption by suppressing the activation of IFN-γ and IL-17 cells by polarizing M2 macrophages. In conclusion, our data indicate that SHED-CM contains active secretions that may have promising efficacy to ameliorate OVX-induced osteopenia. We suggest that SHED-CM has the potential to be used as a novel therapeutic agent to inhibit osteoporosis.

In this study, we attempted to localize the immunoreactivities of podoplanin/E11/gp38 and CD44, a counterpart possessing a high affinity to podoplanin/E11/gp38, as well as endomucin-immunoreactive blood vessels in the regions of odontoblast layers and the underlying sub-odontoblastic layers in murine tooth germs. Endomucin-reactive small blood vessels were scattered throughout the dental papillae of the tooth germs at postnatal day 1 but came to be localized close to the odontoblast/sub-odontoblastic layers until day 3. After postnatal day 5, small blood vessels were seen in odontoblast cell layers, while blood vessels with relatively larger diameters were seen forming in sub-odontoblastic layers. Immunoreactivities of podoplanin/E11/gp38 and CD44 were not detectable in the cells of dental papillae facing the inner enamel epithelium at postnatal day 1. However, at around postnatal days 3-5, podoplanin/E11/gp38 was localized in the odontoblast layer but not in the sub-odontoblastic layer, whereas CD44 was observed in the sub-odontoblastic layer but not in the odontoblast layer. The exclusive immunolocalization of podoplanin/E11/gp38 and CD44 in the odontoblast layers and sub-odontoblastic layers was seen after postnatal day 3 of the tooth germs, when the mesenchymal cells of dental papillae have already differentiated into mature odontoblasts at the cusp tip. Taken together, it seems likely that endomucin-reactive small blood vessels extended to the podoplanin/E11/gp38-positive odontoblast layers, whereas endomucin-reactive large blood vessels were already present in CD44-immmunopositive sub-odontoblastic layer, indicating the cellular regulation on the vascularization of endomucin-reactive endothelial cells during odontogenesis of the tooth germs.

Background/purpose: Circadian rhythm is an endogenous daily variation observed in most physiological functions including salivary secretion. Irregular lifestyle causes many diseases such as obesity and sleep disorders. The aim of this study is to examine the effects of the timings of sleep and meal on the prevalence of dental caries. Materials and methods: Study was conducted at university hospital in Japan. We asked 230 children (1-16 years old) to record the following life habits for 8 days: waking time, bedtime, mealtimes, snacking frequency, and tooth brushing frequency. We analyzed sleep habits from all data and compared dental caries and life habits using data from subjects with primary (2-7 years old) or permanent (11-16 years old) dentition period. Results: The number of dental caries assessed using the decay or filled teeth (dft) index correlated with bedtime, supper time, regularity of supper time, and snacking frequency in subjects with primary dentition. Multiple regression analysis revealed that bedtime and snacking frequency were mutually independent risk factors for dental caries. No correlations were found between the prevalence of dental caries and other measurement items. The number of caries correlated with the regularity of supper time and age in subjects with permanent dentition. Conclusion: Children with daily life habits associated with eveningness have a higher prevalence of dental caries. (C) 2019 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.

Objective The objective of the present in vitro study was to evaluate the influence of endodontic irrigation systems on the removal of smear layer and ion diffusion of calcium hydroxide through dentinal tubules in root external resorption models. Materials and methods Forty single-rooted teeth were divided into four groups (G1, G2, G3, and G4) according to the irrigation regimens: G1, saline solution; G2, 10% sodium hypochlorite with ultrasonic irrigation; G3, 14% EDTA with ultrasonic irrigation; G4, 14% EDTA with ultrasonic irrigation → 10% sodium hypochlorite with ultrasonic irrigation. Ultrasonic irrigation lasted 45 seconds and all the roots were irrigated with 2 mL of saline solution. In experiment 1, the samples were observed on the root canal wall using scanning electron microscope and the percentage of opened dentinal tubules (POD) was calculated. Experiment 2 evaluated the diffusion of calcium ions through dentinal tubules. Results In the middle region of root canals, the mean POD values were 0.11, 5.02, 82.17 and 96.72 in G1, G2, G3, and G4, respectively. In the apical region of root canals, the mean POD values were 0.06, 0.43, 4.41, and 12.70 in G1, G2, G3, and G4, respectively. The diffusion of calcium ions in G4 was significantly high in all groups. Conclusion This study demonstrated that a combination of EDTA and sodium hypochlorite with ultrasonic irrigation was most effective in removing the smear layer and ion diffusion from the root canal to the surrounding media.

Special AT-rich sequence-binding protein 2 (SATB2)-associated syndrome (SAS) is characterized by alterations of SATB2. Its clinical features include intellectual disability and craniofacial abnormalities, such as cleft palate, dysmorphic features, and dental abnormalities. Here, we describe three previously undiagnosed, unrelated patients with SAS who exhibited dental abnormalities, including multiple odontomas. Although isolated odontomas are common, multiple odontomas are rare. Individuals in families 1 and 3 underwent whole-exome sequencing. Patient 2 and parents underwent targeted amplicon sequencing. On the basis of the hg19/GRCh37 reference and the RefSeq mRNA NM_001172517, respective heterozygous mutations were found and validated in Patients 1, 2, and 3: a splice-site mutation (chr2:g.200137396C > T, c.1741-1G > A), a nonsense mutation (chr2:g.200213750G > A, c.847C > T, p.R283*), and a frame-shift mutations (chr2:g.200188589_200188590del, c.1478_1479del, p.Q493Rfs*19). All mutations occurred de novo. The mutations in Patients 1 and 3 were novel; the mutation in Patient 2 has been described previously. Tooth mesenchymal cells derived from Patient 2 showed diminished SATB2 expression. Multiple odontomas were evident in the patients in this report; however, this has not been recognized previously as a SAS-associated phenotype. We propose that multiple odontomas be considered as an occasional manifestation of SAS.

Megacystis microcolon intestinal hypoperistalsis syndrome (MMIHS) is a rare congenital anomaly characterized by abdominal distension, distended non-obstructive urinary bladder, microcolon, and intestinal hypoperistalsis. Although facial manifestations have been reported, oral findings in MMIHS patients have never been described. Here, we report the case of a 4-year 10-month-old girl with MMIHS who visited our clinic for delayed tooth eruption. Oral examination revealed that she had a high and narrow palate, gingival hyperplasia, impacted teeth, and delayed eruption. X-ray images showed no congenital lack of primary and permanent teeth. This is the first report of oral findings of an MMIHS patient.

Purpose Proper root canal irrigation is essential for endodontic treatment. To evaluate the effectiveness of several root irrigation regimens, the extent of the removal of smear layer from the root canal in primary teeth was analyzed. Methods Fifteen extracted human primary teeth were divided into five groups and subjected to the following irrigation regimes: Group 1, needle irrigation with saline; Group 2, needle irrigation with 5% sodium hypochlorite (NaOCl); Group 3, ultrasonic irrigation with 5% NaOCl; Group 4, needle irrigation with 14% ethylene diamine tetraacetic acid (EDTA); Group 5, ultrasonic irrigation with 14% EDTA. The percentage of open dentinal tubules (POD) in the irrigated root canal was analyzed using a scanning electron microscope. Results POD for Groups 4 and 5 were significantly higher than Groups 1, 2, and 3 ( p p Conclusion These results suggest that root canal irrigation with NaOCl using an ultrasonic effectively removed smear layer from the root canal in primary teeth.

In this study, we investigated the cytocompatibility of ceramic nanoparticles on different types of cells. All ceramics nanoparticles investigated in this study except Copper oxide (CuO) exhibited good cytocompatibility and cell viability (90% or more) even at 20 ppm concentration. In contrast, CuO nanoparticles caused cell inflammation, and their effect depended on their particle size. Confocal fluorescence microscopy measurements indicated that some particles had penetrated into the cells. These results indicate that except CuO nanoparticles, all other ceramic nanoparticles reported herein exhibited excellent cytocompatibility even for lung epithelial cells.

We assessed the biocompatibility of nano-sized ceramic particles with several cells types. Though these particles have less than 100 nm in diameter, they act as submicron-sized particles in saline by aggregation that was estimated using laser diffraction particle size analysis (LDS). they act as submicro-sized particles in saline by aggregation based on laser diffraction particle size analysis (LDS). Several types of cells (osteoblasts, osteosarcoma and hepatocyte cells) were exposed to these particles and their cytocompatibility was estimated. Not only the cytotoxic assay but also their static and dynamic morphology under nanoparticles exposure were investigated. The intercellular uptake of particles was determined using a confocal fluorescence microscope. The particles used in this study did not inhibit cellular activity or growth even when their concentrations were high. Only copper oxide particles caused acute cytotoxicity depending on the particle size. The cytotoxicity assay, dynamic behavior of the nanoparticle-exposed cells and their examination under a confocal fluorescence microscope suggests that the irritative reaction was induced by contact between the cells and particles, whereas eluted copper ions are not dominant factor. These results indicate that nano-sized particles used in this study have excellent biocompatibility except copper oxide ones.

Stressful stimuli induced by immobilization are perceived as acute stress in rats. This acute stress activates corticotropin-releasing hormone (CRH) neurons in the hypothalamic paraventricular nucleus (PVN), resulting in stimulation of the hypothalamic-pituitary-adrenal (HPA) axis. The ventral ascending noradrenergic bundles (V-NAB) from the brainstem innervate the PVN. To investigate the relationship between the response of the HPA axis and the V-NAB, we examined changes in plasma corticosterone, the final output of the HPA axis, and extracellular noradrenaline (NA) in the PVN following immobilization stress in rats that received bilateral 6-hydroxydopamine (6-OHDA) lesions of the V-NAB. 6-OHDA microinjection into the V-NAB reduced the magnitude of the responses of plasma corticosterone and extracellular NA in the PVN following immobilization stress. Our results suggest that V-NAB innervation of the PVN is involved in immobilization stress-induced activation of the HPA axis.

To corroborate the hypothesis that mastication affects the motivation to get food, we examined the effects of dietary consistency on the development of meal anticipation in locomotor activity of rats subjected to restricted daily feeding (RF), in which food supply was restricted to a fixed time each day. RF of both liquid and solid meals produced anticipatory locomotor activity. However, the strength of the activity in rats subjected to RF of liquid meal was lower than that in rats subjected to RF of solid meal. These results suggest that the feeding-associated circadian oscillation that developed by feeding with liquid meal is less potent than that in the case of feeding with solid meal. Furthermore, mastication for digesting solid meal might be one of the factors that determine the strength of the feeding-associated circadian oscillation.

In this study, we produced europium-doped yttoria (Y2O3:Eu) nanoparticles and investigated their photoluminescent properties and biocompatibility. The Y2O3:Eu nanoparticles showed excellent photoluminescent properties and cytocompatibility. We also analyzed the photophysical properties of the nanoparticles in PMMA films. When the Y2O3:Eu nanoparticles were incorporated in the polymer film, they showed a strong red emission spectrum, similar to that seen with the particles alone. Energy dispersive X-ray spectroscopy (EDS) measurements indicated that the particles were distributed homogeneously in the PMMA film. Such materials could be applied not only to optoelectronic devices but also to biomedical applications such as bioimaging tools or luminescent medical/dental adhesive materials.

This study was performed in order to determine how immobilization stress in the early postnatal period or in the late postnatal period affects growth in the developing rat, and the response of the hypothalamus-pituitary-adrenocortical (HPA) axis in adult rats subjected to subsequent novel stresses. In addition, the effects of maternal deprivation (MD) within the same period of exposure to immobilization stress were also examined. We used two different types of immobilization stress and two different types of MD: immobilization stress for 30 min per day from postnatal day 7 (P7) to P13 (IS-E group); immobilization stress for 30 min from P15 to P21 (IS-L group); MD for 30 min per day from P7 to P13 (MD-E group); and MD for 30 min per day from P15 to P21 (MD-L group). The IS-E group showed a significant reduction in body weight that was maintained until at least P40 when compared with the control group. On the other hand, the IS-L group showed a significant reduction in body weight at only postnatal day (P) 20 when compared with the control group. Furthermore, the IS-E group showed a larger HPA response to novel stress than the IS-L and control groups in adulthood. The MD-E group showed a significant reduction in body weight that was maintained until at least P20 when compared with the control group, but did not show a larger HPA response to novel stress, except at T30 (30 min after exposure to novel stress) than the control group in adulthood. The MD-L group did not show a significant reduction in body weight or increased HPA response when compared with control rats. These results suggest that repeated immobilization stress, but not MD, in the early postnatal period induces long-term effects on growth and HPA response to novel stress in adulthood. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

We investigated morphologies, size distributions and elemental compositions of dental debris formed by cutting/grinding teeth or dental alloys. The average size of debris formed by cutting/grinding dental alloy was around 100 μm and that of teeth was 20 μm. The debris formed by grinding with diamond or carborundum point had isotropic irregular shape, while the debris formed by cutting with carbide bar had characteristic lathe-cut shape. The elemental analysis indicated that the debris formed by grinding dental alloy with carborundum point consisted of not only the particles of the alloy but also the particles of Si compounds with the size of around 10 μm. The particles of Si compounds would be formed by abrasion of the grinding instrument (carborundum, SiC). Similarly, the debris formed by grinding with diamond point also contained submicro-sized particles consisting of C compounds. The results indicate that the morphology and composition of dental debris are varied depending on the combination between the workpiece and the cutting/grinding materials and that the dental debris consist of both the workpiece and the cutting/grinding materials in some combination. In addition, some of the debris of tooth had the size less than 2 μm, which has a potential to induce inflammation. Though the inflammation can be expected at low level, it is required to investigate the details in future.

In this study, we examined the effects of fissure sealants on inhibition of demineralization of primary teeth using an automatic pHcycling system. Three fissure sealants were used: Teethmate F-1 2.0 (TM), BeautiSealant (BS), and Fuji III LC (IIILC). Using an automatic pH-cycling system, the specimens (n=12) were repeatedly demineralized and remineralized. Specimens were subjected to transverse microradiography (TMR), and changes in integrated mineral loss (IML) and lesion depth (Ld), indicated as ΔIML and ΔLd, respectively, were calculated. In addition, fluoride levels in the enamel were assessed using microparticle-induced gamma-ray emission/particle-induced X-ray emission (n=3). IIILC showed the lowest values for ΔIML and ΔLd, followed by BS and then TM. The highest amount of fluorine in the enamel was observed for IIILC, followed by TM and BS. All fissure sealants inhibited demineralization in primary teeth.

Cytotoxicity and cell behavior to micro / nanoparticles of TiO2 and CuO was evaluated using the viability measurement and time-lapse observation. After cultured, osteoblastic cells MC3T3-E1 were exposed to particles. After 24 hour exposure, their morphology was observed using a SEM and the viability was measured. Cells exposed to TiO2 indicated no or very low decrease of viability. The results were independent of the particle size. On the other hand, the viability of cells exposed to CuO decreased with the concentration, and showed the size dependence. The nanosized CuO indicated higher toxicity compared with micro-sized one. Dynamic behavior of cells exposed to nanoparticles, was succeeded to observe in a time-lapse method for 24 hours. The observation showed that the cells exposed to CuO became dead after forming a spherical shape. This is consistent with the image taken by SEM. Time-lapse observation made it possible to see the dynamic reaction process from cell contact to particles at first, the following cell activity response and finally to cell death, which revealed a considerably different morphology from the static cell observed after fixation by conventional method.

We succeeded in determination the biodistribution of several nano-sized particles administered to mice through the tail vein. After administration, these particles were observed in the lung, liver and spleen. The distribution behaviors depend upon not only chemical species but also the particles size. To estimate their cytocompatibility, these particles were exposed to osteoblastic cell at several concentrations. When the concentration reached at 10 ppm, their viability remained at 80% or more even nano-sized particle contained rare earth element. Only CuO particles indicated the viability decrease. The effect depended on the particle size. These results suggested that the chemical species played a dominant key in the biodistribution and biocompatibility of nanoparticles compared with the size-effect.

In this study, we prepared two-types of water-dispersible carbon nanotubes (CNTs) and investigated their biodistribution in mice as well as bio-/cyto-compatibility. After administration, their organs were excised at various post-injection times, then observed using both optical and transmission electron microscopy (TEM). The color of the liver and lung markedly darkened, suggesting that administered CNTs reached these organs. By TEM observation, the CNTs were found in the liver and lung. They were observed even in the kidney and spleen, though their distributions in those organs were very low compared with that in liver and lung. Therefore, most of the administered CNTs would be accumulated in the liver or lung. However, the time profile of the body weight of CNT-administered mice was close to that of control mice. In addition, we estimated the cytocompatibility of the water-dispersible CNTs for hepatocytes. According to a TNF-alpha assay of the cells cultured with CNTs, the expression level was almost the same as that of the control. These results suggested that the water-dispersible CNTs have good bio-/cyto-compatibility under this condition.

Introduction The purpose of this study was to evaluate the cytotoxicity of mineral trioxide aggregate (MTA) and its potential detoxification by an antioxidant amino acid, N -acetylcysteine (NAC). Methods Rat dental pulp cells extracted from rat maxillary incisors were directly cultured on MTA with or without NAC in culture me-dium. The number of cells and their spreading behavior were both assessed 24 hours after seeding. The intracellular levels of reactive oxygen species (ROS) and glutathione (GSH) were also assessed after 24 hours of culture. Results The number of cells attached to MTA was 60% greater when NAC was added to the culture medium. In addition, the area and perimeter of the cells were found to be 2-fold greater in the culture containing NAC. Cells cultured on MTA alone showed large ROS concentrations, which disappeared when the medium was supplemented with NAC. The intracellular GSH level, however, increased 3.5-fold with NAC addition. Conclusions This study demonstrated that the presence of NAC in environments can substantially improve attachment and spreading behaviors of dental pulp cells on MTA. This biological effect was associated with an im-provement in the cellular redox system by NAC and warrants further exploration of NAC for determining its therapeutic value in improving the biocompatibility of MTA.

Development of scaffolds consisting of micro-/nano-sized materials have attracted a great deal of attention for their potential use in tissue engineering tools. We prepared a cell culture scaffold of carbon nanotubes, which is a typical bio-inert nanomaterial, and then investigated the surface morphology and properties. A three-dimensional nano-level network structure was observed using a scanning electron microscope and an atomic force microscope. The scaffold also exhibited excellent protein absorption. In order to apply the obtained scaffold to the cultivation of osteoblast cells, the cytocompatibility was comparable to that of a conventional cell culture dish. [DOI: 10.1380/ejssnt.2011.80]

Current dental restorative materials are only used to fill the defect of hard tissues, such as dentin and enamel, because of their cytotoxicity. Therefore, exposed dental pulp tissues in deep cavities must be first covered by a pulp capping material like calcium hydroxide to form a layer of mineralized tissue. However, this tissue mineralization is based on pathological reaction and triggers long-lasting inflammation, often causing clinical problems. This study tested the ability of N-acetyl cysteine (NAC), amino acid derivative, to reduce cytotoxicity and induce mineralized tissue conductivity in resin-modified glass ionomer (RMGI), a widely used dental restorative material having dual cure mechanism. Rat dental pulp cells were cultured on untreated or NAC-supplemented RMGI. NAC supplementation substantially increased the percentage of viable cells from 46.7 to 73.3% after 24-h incubation. Cell attachment, spreading, proliferative activity, and odontoblast-related gene and protein expressions increased significantly on NAC-supplemented RMGI. The mineralization capability of cells, which was nearly suppressed on untreated RMGI, was induced on NAC-supplemented RMGI. These improved behaviors and functions of dental pulp cells on NAC-supplemented RMGI were associated with a considerable reduction in the production of intracellular reactive oxygen species and with the increased level of intracellular glutathione reserves. These results demonstrated that NAC could detoxify and functionalize RMGIs via two different mechanisms involving in situ material detoxification and antioxidant cell protection. We believe that this study provides a new approach for developing dental restorative materials that enables mineralized tissue regeneration.

We incidentally encountered an anomaly of the cervical vertebrae during orthodontic examination of an 8-year-old boy with cleft lip and palate. Klippel-Feil syndrome was diagnosed by the orthopedic specialist to whom he had been referred for detailed examination. This case report shows the results of axial multislice-helical computed tomography with three-dimensional reconstructions of the cervical vertebrae. Furthermore, we evaluated the frequency of congenital anomalies on lateral cephalogram in patients with cleft lip and palate or cleft palate and non-cleft controls from among all patients in our orthodontic clinic.

The aim of this study was to evaluate calcium charge and release of conventional glass-ionomer cement (GIC) containing nanoporous silica (NPS). Experimental specimens were divided into two groups: the control (GIC containing no NPS) and GIC-NPS (GIC containing 10 wt % NPS). The specimens were immersed in calcium chloride solutions of 5 wt % calcium concentration for 24 h at 37 &deg, C, whereupon the calcium ion release of the specimens was measured. The calcium ion release behavior of GIC-NPS after immersion in the calcium solution was significantly greater than that of the control. Scanning electron microscopy and electron-dispersive X-ray spectroscopy results indicated that calcium penetrated inside the GIC-NPS specimen, while the calcium was primarily localized on the surface of the control specimen. It was demonstrated that NPS markedly improved the calcium charge and release property of GIC.

The internal distribution behavior of micro/nanosized ceramics and metal particles administered into the tail vein of mice was determined using magnetic resonance imaging, scanning X-ray analytical microscopy and inductively coupled plasma-atomic emission spectroscopy. After administration through the tail vein of mice, the particles circulated by blood flow reached and then remained temporarily in certain organs. In this study, we determined that the distribution behaviors in body depend upon the chemical species and the size of the particles.

Idiopathic osteosclerosis (IO) is a localized, well-defined, intrabony radiopaque lesion within cancellous bone. The causes of IO are still unknown and most lesions are nonexpansile and asymptomatic, so they are often detected incidentally on radiographic examination for other purposes. In the case of jaw lesions, IO is considered to be of no clinical significance and usually requires no treatment. This paper describes two clinical cases about the long-term treatments and observations of mandibular IO in adolescents. The lesions were associated with abnormal tooth root formation and tooth malposition. In these cases, the orthodontic treatments finished successfully without any complication despite the lesions. IO in the jaw needs regular follow-up to ensure normal orofacial development during adolescence.

Imogolite is a naturally occurring hydrous aluminosilicate clay mineral. It has nano-tubular structure similar to that of single-walled carbon nanotubes. Imogolite is a subject of interest in the pedological field, but to date there has been no bioapplications of this substance. In this study, we investigated the cellular response of osteoblast-like cells to imogolite scaffolds. To reveal the morphology, proliferation and osteoblastic functional mineralization, we cultured human osteoblast-like cells (Saos-2) and mouse osteoblast-like cells (MC3T3-E1) on the scaffolds. The surface characteristics of the imogolite scaffold were drastically changed depending on the amount of imogolite on the dish. With the increase of imogolite concentration, the surface morphology of scaffolds changed from an island-like shape in random orientation to a self-organized fiber texture aligned in the same direction, and finally full coverage in a random orientation with plural layers. Both types of osteoblast were widely spread on the imogolite scaffolds compared to their appearance in a conventional culture dish (control). The proliferation of the two types of osteoblast showed potentially useful trends. In cellular function, there was greater mineralization of both types of osteoblast on imogolite scaffolds than that of the control. Saos-2 and MC3T3-E1 cells showed good biocompatibility in addition to the enhanced osteoblastic mineralization. Therefore, imogolite is expected to be useful as a scaffold material for bone tissue engineering.

Carbon nanotubes (CNT) and their derivatives with different structure and compositions have unique features. In the present study, cell proliferation was performed on various nanotubes such as single walled CNTs, multiwalled CNTs and imogolite which is nanotubes of aluminosilicate. SEM observation of the growth of osteoblast-like cells cultured on CNTs showed the morphology fully developed for the whole direction, which was different from that extended to the one direction on the usual scaffold. Numerous filopodia were grown from cell edge, extended far long and combined with CNT meshwork. Apatite precipitation in simulated body fluid, affinity for proteins and saccharides, and nanosize meshwork structure with large porosity would be the properties responsible for these cell adhesion and growth. Imogolite showed the similar properties to CNTs. Nanotubes could be the favorable materials for biomedical applications.

Introduction Recently, mineral trioxide aggregate (MTA) has been routinely used for endodontic treatment. It is well-known that MTA induced secondary dentin formation in pulp cavity when it was applied to dentin, whereas its cytotoxicities were unclear. The purpose of this study was to evaluate the effect of MTA on rat clonal dental pulp cells, RPC-C2A. Methods This study was conducted to observe the response of RPC-C2A cells on MTA with reverse-transcriptase polymerase chain reaction, Western blot analysis, and enzyme immunoassay. Data were compared by analysis of variance. Statistical significance was established at P Results MTA significantly caused an up-regulation of cyclooxygenase-2 (COX-2) and inducible form of nitric oxide synthase (iNOS) mRNA expression. Furthermore, MTA caused inhibitory kappa B (IκB) phosphorylation and translocation of nuclear factor–kappa B (NF-κB) subunits to nucleus. Curucumin, an inhibitor of NF-κB activation, suppressed MTA-induced COX-2 and iNOS mRNA expressions. In addition, MTA increased the production of prostaglandin E2 in comparison with the controls. Conclusions MTA induces inflammation via NF-κB signaling system.

MicroRNAs (miRNAs) are small non-coding RNAs that are emerging as important post-transcriptional gene regulators. miR-206 is unique in that it is expressed only in skeletal muscle, including the myoblastic C2C12 cell line. In C2C12 cells, miR-206 expression was reduced dramatically after bone morphogenetic protein (BMP)-2 treatment. The down-regulation of miR-206 expression was also observed after co-transfection with constitutively-active Smad1 and Smad4, which are the intracellular signaling molecules of the BMP pathway. BMP-2 also reduced miR-206 expression in the presence of α-amanitin in a similar manner to that in the absence of α-amanitin. Moreover, the expression of pri-miR-206 was increased upon BMP-2 treatment for 6 h compared to that in the absence of BMP-2. These results suggested that BMP-2 down-regulates miR-206 expression at the post-transcriptional level, by inhibiting the processing of pri-miR-206 into mature miR-206, and that BMP-2 could regulate miRNA biogenesis by a novel mechanism.

The Wiskott-Aldrich syndrome protein (WASP), which is defective in Wiskott-Aldrich syndrome (WAS) patients, is an intracellular protein expressed in non-erythroid hematopoietic cells. Previously, we have established methods to detect intracellular WASP expression in peripheral blood mononuclear cells (PBMNCs) using flow cytometric analysis (FCM-WASP) and have revealed that WAS patients showed absent or very low level intracellular WASP expression in lymphocytes and monocytes, while a significant amount of WASP was detected in those of normal individuals. We applied these methods for diagnostic screening of WAS patients and WAS carriers, as well as to the evaluation of mixed chimera in WAS patients who had previously undergone hematopoietic stem cell transplantation. During these procedures, we have noticed that lymphocytes from normal control individuals showed dual positive peaks, while their monocytes invariably showed a single sharp WASP-positive peak. To investigate the basis of the dual positive peaks (WASP(low-bright) and WASP(high-bright)), we characterized the constituent linage lymphocytes of these two WASP-positive populations. As a result, we found each WASP(low/high) population comprised different linage PBMNCs. Furthermore, we propose that the difference between the two WASP-positive peaks did not result from any difference in WASP expression in the cells, but rather from a difference in the structural and functional status of the WASP protein in the cells. It has been shown that WASP may exist in two forms; an activated or inactivated form. Thus, the structural and functional WASP status or configuration could be evaluated by flow cytometric analysis.

Repeated or chronic stress is known to produce structural and functional changes in the rat brain, and in particular, alter the response of the hypothalamic -- pituitary -- adrenal (HPA) axis to subsequent new stress. Occlusal disharmony via placement of acryl cap on the lower incisors of rats is perceived as chronic stress. To determine the response of the HPA axis to subsequent new stress in rats with occlusal disharmony, we measured plasma corticosterone levels in these rats after subjecting them to new stress. Plasma corticosterone levels in rats with and without incisal cap increased and reached a peak 30 min after exposure to the new stress. However, a later decrease in plasma corticosterone levels from peak levels was found in rats with incisal cap compared with rats without incisal cap. This finding suggests that occlusal disharmony alters the response of the HPA axis to subsequent new stress.

Wnt/beta-catenin signaling plays an important role in the developing skeletal system. Our previous studies demonstrated that Wnt/beta-catenin signaling inhibits the ability of bone morphogenetic protein (BMP)-2 to suppress myotube formation in the multipotent mesenchymal cell line C2C12 and that this inhibition is mediated by Id1. In this study, we examined the role of intracellular signaling by Wnt/beta-catenin and BMP-2 in regulating the expression of osteoprotegerin (OPG) and of the receptor activator of NFkappaB ligand (RANKL). OPG expression was induced by Wnt/beta-catenin signaling in C2C12 cells and osteoblastic MC3T3-E1 cells. Silencing of glycogen synthase kinase-3beta also increased OPG expression. In contrast, R expression was suppressed by Wnt/beta-catenin signaling. In a transfection assay, beta-catenin induced the activity of a reporter gene, a 1.5 kb fragment of the 5'-flanking region of the OPG gene. Deletion and mutation analysis revealed that Wnt/beta-catenin signaling regulates transcription of OPG via a promoter region containing two Wnt/beta-catenin responsive sites. BMP-2 enhanced Wnt/beta-catenin-dependent transcriptional activation of the OPG promoter. In response to BMP-2 stimulation, Smad 1 and 4 interacted with Wnt/beta-catenin responsive sites. These results show that the regulation of OPG expression is mediated through two transcription pathways that involve the OPG promoter.

Nanoparticles may invade directly into the internal body through the respiratory or digestive system and diffuse inside body. The behavior of nanoparticles in the internal body is also essential to comprehend for the realization of DDS. Thus it is necessary to reveal the internal dynamics for the proper treatments and biomedical applications of nanoparticles. In the present study the plural methods with different principles such as X-ray scanning analytical microscope (XSAM), MRI and Fluorescent microscopy were applied to enable the observation of the internal diffusion of micro/nanoparticles in the (1) whole body level, (2) inner organ level and (3) tissue and intracellular level. Chemical analysis was also done by ICP-AES for organs and compared with the results of XSAM mapping.

Repeated immobilization stress tests in the early postnatal period were performed to determine the effects on the growth of developing rats as well as the response of the HPA axis to subsequent novel stress in adulthood. In addition, effects of maternal deprivation (MD) with the same period of the exposure to immobilization stress were also examined. We used 2 different types of immobilization stress and 2 different types of MD: immobilization stress for 30 min/day from postnatal day 7 (P7) to P13 (IS7-13 group); immobilization stress for 30 min on P7 (IS7 group); MD for 30 min/day from P7 to P13 (MD7-13 group); and MD for 30 min on P7 (MD7 group). Body weights were lower in the IS7-13 group than in the control group from P10 to P50, although body weight gain in the MD7-13 group was only transiently affected. Stress-induced corticosterone levels in the IS7-13 group were higher than in the control group and did not return to baseline levels until at least 120 min after the termination of stress, whereas temporal variations of stress-induced corticosterone levels did not differ between the IS, MD7-13, MD7, and control groups. Repeated immobilization stress in the early postnatal period induced long-term effects on the growth of developing rats and stress response of the HPA axis to the novel stress in adulthood, although a single immobilization stress, periodic MD, or a single MD had little effect.

A 10 year-3 month-old boy with root resorption of the right central incisor associated with impaction of the right canine in the maxilla was referred to our dental clinic by a private general dental practitioner. He had Down syndrome with slight intellectual impairment and no congenital heart disease. Since the results of the mental development age test indicated that his development age was probably more than 4 years and 8 months, we decided that we could treat the patient by using behavior management techniques. We explained the procedures for comprehensive dental treatment in a simplified manner to the patient by using behavior management techniques. The use of enhanced behavior management techniques enabled him to accept comprehensive dental treatment that included extraction of the central incisor and orthodontic and restorative treatments of the impacted canine. We were able to complete the treatments and obtain a good outcome.

Recently, one-bottle resins adhesives have been developed to reduce the number of clinical steps of resin application. They are now widely used in clinical dental practice. However, little is known regarding the detailed mechanism of bond degradation. Therefore, this study evaluated the durability of one-bottle resin adhesives using long-term water storage testing. Resin-dentin bonded specimens were prepared using five commercially available one-bottle resin adhesives. The specimens were sectioned perpendicular to the adhesive interface to produce beams and stored in distilled water for 24 hours (control), 100, 200, and 300 days. After the water storage, each beam was subjected to a microtensile bond test and then SEM fractography was performed on the fractured surface. Compared to the bond strength at 24 hours after bonding (control), the bond strength of all tested adhesives were significantly decreased after 100 or more days in water. SEM fractography revealed a typical type of deterioration in the adhesive-composite interface that might cause a decline in bond strength after aging.

Autoantibodies to autoimmune enteropathy-related 75 kDa antigen (AIE-75) and villin are disease markers of immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome which is characterized by a peripheral tolerance defect. On the other hand, anti-tryptophan hydroxylase-1 (TPH-1) antibodies are detected in autoimmune polyendocrinopathy, candidiasis, ectodermal dystrophy (APECED), a central tolerance defect, especially when complicated with gastrointestinal dysfunction. However, to date, anti-AIE-75 and anti-villin antibodies or anti-TPH-1 antibodies have not been tested in APECED or IPEX syndrome, respectively. In the present study, we confirmed the disease specificity of both anti-AIE-75 and anti-TPH-1, although anti-villin antibodies were detected in some patients with APECED. Our observation suggests that immunotolerance to AIE-75 depends on the peripheral mechanism, whereas the tolerance to TPH-1 depends on the central mechanisms.

The purpose of this study was to examine changes in functional parameters of patients with anterior crossbite in primary dentition during orthodontic treatment. Occlusal contact area (OCA), average bite pressure (ABP) and integrated occlusal load (IOL) were measured. Data obtained before the start of treatment (period A), data obtained when crossbite had improved (period B) and data obtained when the appliance had been removed (period C) were compared. OCA showed the lowest value in period B, and then gradually increased. ABP increased until period B and then declined or became constant. OCA and IOL showed significant differences in periods A and B and periods B and C (p