著者

Yaeko Hara Hiroshi Shiratsuchi Takaaki Tamagawa Ryosuke Koshi Chihiro Miya Maki Nagasaki Tetsuo Ohyama Shunichi Oka Hideaki Sakashita Tadayoshi Kaneko

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

vol.60, no.3, pp.321-328, 2018 (Released:2018-09-23)

参考文献数

31

被引用文献数

7

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Recently, reports regarding a foreign body in the maxillary sinus have considerably increased, with the majority being iatrogenic cases resulting from dental treatment. This study involves an extensive review of the Japanese literature, including 112 papers from 1978 to 2017. These papers documented total 407 cases of a foreign body in the maxillary sinus. Among the 392 cases for which treatment details were available, the Caldwell-Luc approach was used for 216, the alveolar approach for 116, extraction using nasal endoscopy for 15, and extraction using oral endoscopy for eight. Spontaneous passage occurred in 19 cases, follow-up with medication was used in 17, and “other” was noted in one. This study determined that surgical removal remains the most common method for treating both tooth roots and other foreign bodies and that the Caldwell-Luc approach is used in majority of the surgeries. No marked differences were noted among the removal methods used in relation to the foreign body type.

著者

Serina Taguchi Futoshi Komine Kei Kubochi Ryosuke Fushiki Fumiaki Kimura Hideo Matsumura

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0383, (Released:2018-08-25)

参考文献数

35

被引用文献数

8

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This study examined the effect of silane and phosphate functional monomer on bond strengths between a resin-based luting agent joined to a lithium disilicate ceramic (IPS e.max) and silica (quartz) materials. The e.max and quartz specimens were assigned to 6 groups with different priming/bonding agents, namely, Clearfil Porcelain Bond Activator, Clearfil Photo Bond, Clearfil Photo Bond Universal with Clearfil Porcelain Bond Activator, Clearfil Photo Bond Catalyst with Clearfil Porcelain Bond Activator, Clearfil Photo Bond with Clearfil Porcelain Bond Activator, and unprimed. The corresponding specimens were bonded by using a resin-based luting agent (Panavia V5). Shear bond strengths were determined before and after 5,000 thermocycles. For both the e.max and quartz specimens, the Clearfil Photo Bond Universal with Clearfil Porcelain Bond Activator group had the highest pre- and post-thermocycling bond strength values. Combined use of silane in the acidic environment of a phosphate functional monomer and initiators enhances bond strength of a resin-based luting agent to e.max ceramic and quartz materials.

著者

Miho Obayashi-Ishii Satsuki Saito Daisuke Omagari Masatake Asano Tomohiko Ishigami

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0380, (Released:2018-08-25)

参考文献数

29

被引用文献数

2

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Magnetic attachments are commonly used for overdentures. The deleterious effects of exposure to magnetic flux on human health have not been substantiated so far; nevertheless, there is a need to understand the extent of magnetic field exposure in the oral area resulting from the use of magnetic attachments. The purpose of this study was to investigate the influence of a magnetic field on oral squamous cell carcinoma. Tumor cells cultured on a magnetic plate were compared with those not cultured on a magnetic plate (controls). The cells were seeded at a density of 1 × 105 cells/well and cultured for 6 days. The influence of the magnetic field on cytokine production was examined by cytokine array analysis. Secretion of platelet-derived growth factor-AA (PDGF-AA) was measured by enzyme-linked immunosorbent assay and Western blotting. The expression of PDGF-AA messenger RNA was examined by real-time polymerase chain reaction, whereas nuclear factor-kappa B activity was measured by luciferase assay. The results indicated that the magnetic field inhibited the secretion of PDGF-AA, thereby inhibiting PDGF-AA-induced expression, thus reducing the risk of cancer recurrence.

著者

Shigenori Hirai Yusuke Hayashi Motohiro Ito Toshihiko Amemiya Ko Dezawa Yoshinori Arai Ken-ichiro Ejima Shigeki Shimba Kazuya Honda

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0390, (Released:2018-08-25)

参考文献数

19

被引用文献数

5

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Brain and muscle Arnt-like protein-1 (BMAL1) knockout mice exhibit accelerated aging, abnormal glucose metabolism, and impaired adipocyte differentiation, among other phenotypes, which are effects associated with the BMAL1 gene. No study has investigated temporal changes in the deformation of the mandibular condyle and the presence of calcification in areas surrounding the mandibular condyle. In a study of 12 C57/BL strain mice under inhalation anesthesia, we collected images of the mandibular condyle at 6 weeks after birth and then every 5 weeks from 10 to 25 weeks after birth. At 25 weeks, deformation of the mandibular condyle was seen in 8 of 12 joints in BMAL1 knockout mice and in 2 of 12 joints in wild-type mice. At 20 and 25 weeks, deformation in areas surrounding the mandibular condyle, which are known to undergo calcification, was seen in 2 of 12 joints in BMAL1 knockout mice and in 0 of 12 joints in wild-type mice. BMAL1 knockout mice exhibited premature aging of the mandibular condyle, which suggests that circadian rhythms affect mandibular condyle morphology.

著者

Hiroshi Kudo Osamu Takeichi Kosuke Makino Keisuke Hatori Bunnai Ogiso

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0412, (Released:2018-08-12)

参考文献数

45

被引用文献数

6

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Silent information regulator 2 homolog 1 (SIRT1) inhibits oxidative injury and has anti-inflammatory effects. SIRT1 may be involved in healing of periapical periodontitis; however, SIRT1 expression in periapical periodontitis lesions has not been investigated. This study evaluated SIRT1 expression and a marker of oxidative stress—8-hydroxy-2’-deoxyguanosine (8-OHdG)—in periapical granulomas. First, we used real-time polymerase chain reaction to determine whether U-937 monocytes express SIRT1. U-937 cells treated with the SIRT1 activator resveratrol exhibited the highest SIRT1 mRNA level after 6-h incubation. By contrast, treating cells with the SIRT1 inhibitor sirtinol returned SIRT1 expression level to that of the control. In addition, immunocytochemical analysis using cytospin specimens showed that U-937 cells co-expressed SIRT1 and Ki-67. Dual-color immunofluorescence imaging showed that round cells in periapical granulomas co-expressed SIRT1 and 8-OHdG; however, neither was expressed in healthy gingival tissues. The number of 8-OHdG-expressing cells was significantly greater than the number of SIRT1-expressing cells. Our findings suggest that macrophages express SIRT1 and that wound healing in periapical granulomas is enhanced by a SIRT1-mediated reduction in the level of oxidative stress.

著者

Takanobu Yamamoto Akira Hasuike Ryosuke Koshi Yasumasa Ozawa Manami Ozaki Tatsuya Kubota Shuichi Sato

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0362, (Released:2018-08-12)

参考文献数

16

被引用文献数

3

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We used radiological and histological analyses to evaluate the effects of mechanical barrier permeability in a rat model of calvarial guided bone augmentation (GBA). The calvaria of 20 rats were exposed, and one of four types of plastic caps (an occlusive cylindrical plastic cap; a plastic cap with no top; a plastic cap with three holes; and a plastic cap with four holes) was randomly placed on both sides. Newly generated bone in the plastic caps was evaluated with micro-computed tomography (micro-CT) and histological analysis. Micro-CT volumetric analysis and decalcified hematoxylin and eosin-stained sections showed that GBA barrier permeability was inversely associated with the quantity of augmented bone obtained. Masson’s trichrome staining showed that collagen in newly generated bony tissue was more mature in plastic caps with three holes than in those with more-permeable or more-occlusive barriers. Bone augmentation was inhibited in specimens exhibiting invasion of soft tissue through penetrating holes, and barrier permeability was associated with the quantity of augmented bone developed. In conclusion, moderate barrier permeability is optimal for development of mature augmented bone.

著者

Ryosuke Murayama Yuko Nagura Kabun Yamauchi Nobuyuki Moritake Masayoshi Iino Ryo Ishii Hiroyasu Kurokawa Masashi Miyazaki Yumiko Hosoya

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0256, (Released:2018-07-09)

参考文献数

40

被引用文献数

5

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We used optical coherence tomography to examine the effect of a coating material containing surface reaction-type pre-reacted glass-ionomer (S-PRG) filler on primary enamel demineralization in 18 extracted human primary teeth. The pulp was removed, and each tooth was ultrasonically cleaned with distilled water. Six teeth were treated with 0.1-M lactic acid buffer solution (De group). In the second group (n = 6), a thin film of coating material was applied before demineralization (PRG group). A third group (Control group; n = 6) was maintained in artificial saliva. Using optical coherence tomography, we measured peak signal intensity (dB) and width at 1/e2 (µm) at predetermined locations on the enamel surface and calculated integrated values. All data were analyzed with ANOVA and the Tukey-Kramer test (α = 0.05). Although changes in integrated values differed between groups, there was a small but significant increase in the Control group and a small but significant decrease in the De group. In the PRG group, integrated values were significantly higher at 7 days after the start of the experiment and significantly increased thereafter. Our findings indicate that a coating material containing S-PRG fillers may prevent primary enamel demineralization.

著者

Kyoko Mukaida Kotoe Mayahara Rina Sanuki-Suzuki Takahiko Tamura Noriyoshi Shimizu

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

vol.60, no.2, pp.316-319, 2018 (Released:2018-06-20)

参考文献数

7

被引用文献数

3

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For treatment of severe bimaxillary protrusion in adults, a condition known to be among the most difficult to manage, both the maxillary and mandibular anterior teeth must be fully retracted using all the extraction space available. This article reports the treatment of an adult with severe high-angle bimaxillary protrusion. To correct the protrusion of the anterior teeth, orthodontic anchor screws (OASs) were used to provide absolute anchorage during anterior retraction. Acceptable occlusion, facial profile, and balance were achieved. OASs appear to be very useful for treatment of severe bimaxillary protrusion in adults.

著者

Hiroyasu Koizumi Takaya Ishii Tomoyo Okazaki Masahiro Kaketani Hideo Matsumura Takayuki Yoneyama

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

vol.60, no.2, pp.285-292, 2018 (Released:2018-06-20)

参考文献数

38

被引用文献数

20

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The castability, mechanical properties, and fracture characteristics of Ti-15Mo-5Zr-3Al alloy were compared with those of Ti-6Al-7Nb alloy and pure titanium (CP Ti) for application of this β-type titanium alloy in cast dental prostheses. Cast specimens were prepared with a centrifugal casting machine. A tensile test was performed according to ISO standard 22674. The castability index for Ti-15Mo-5Zr-3Al was lower than those for Ti-6Al-7Nb and CP Ti. The tensile strength of Ti-15Mo-5Zr-3Al was 852 MPa, which was lower than that of Ti-6Al-7Nb and higher than that of CP Ti. The proof strength of Ti-15Mo-5Zr-3Al was 799 MPa, which was comparable to that of Ti-6Al-7Nb and higher than that of CP Ti. The elastic modulus of Ti-15Mo-5Zr-3Al was 81.0 GPa, which was lower than the values for Ti-6Al-7Nb and CP Ti. Elongation of Ti-15Mo-5Zr-3Al was 5.1%, which was comparable to that of Ti-6Al-7Nb and less than that of CP Ti. The shape of the fractured segment was narrower for Ti-15Mo-5Zr-3Al than for Ti-6Al-7Nb and CP Ti. The deformation characteristics of Ti-15Mo-5Zr-3Al may result in decreased stress relative to increased strain during plastic deformation in the stress-strain diagram. In conclusion, Ti-15Mo-5Zr-3Al alloy has a low elastic modulus and exhibits limited ductile plastic deformation in cast dental prostheses.

著者

Moeko Kato Yasuhiro Namura Takayuki Yoneyama Noriyoshi Shimizu

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0356, (Released:2018-05-31)

参考文献数

23

被引用文献数

5

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This study investigated the effect of the vertical position of the canine on changes in the frictional/orthodontic (F/O) force ratio of nickel-titanium (Ni-Ti) archwires during the initial levelling phase of orthodontic treatment. Frictional and orthodontic forces were measured by using low-friction brackets and Ni-Ti archwires with three different cross-sectional sizes and force types. To simulate canine malocclusion (first premolar extraction case), the upper right canine was displaced gingivally by 1 to 3 mm and the inter-bracket distance between the upper right lateral incisor and second premolar was set at 15 mm or 20 mm. A three-point bending test was performed to measure the orthodontic force of each Ni-Ti archwire. Frictional forces were measured with a universal testing machine and dental arch models by pulling parallel to the end of the archwire at a crosshead speed of 0.5 mm/min. F/O force ratio was calculated and analysed statistically. At a displacement of 3 mm, few archwires had F/O force ratios of less than 1.0, at which orthodontic force overcame frictional force, thus ensuring extrusion of the canine. For effective tooth movement, orthodontists should use Ni-Ti archwires with an F/O force ratio of less than 1.0.

著者

Jun Lee Chisato Yamate Masato Taira Masamichi Shinoda Kentaro Urata Mitsuru Maruno Reio Ito Hiroto Saito Nobuhito Gionhaku Toshimitsu Iinuma Koichi Iwata

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0238, (Released:2018-05-24)

参考文献数

34

被引用文献数

2

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Prefrontal cortex activity is modulated by flavor and taste stimuli and changes during swallowing. We hypothesized that changes in the modulation of prefrontal cortex activity by flavor and taste were associated with swallowing movement and evaluated brain activity during swallowing in patients with dysphagia. To evaluate prefrontal cortex activity in dysphagia patients during swallowing, change in oxidized hemoglobin (z-score) was measured with near-infrared spectroscopy while dysphagia patients and healthy controls swallowed sweetened/unsweetened and flavored/unflavored jelly. Total z-scores were positive during swallowing of flavored/unsweetened jelly and negative during swallowing of unflavored/sweetened jelly in controls but negative during swallowing of sweetened/unsweetened and flavored/unflavored jelly in dysphagia patients. These findings suggest that taste and flavor during food swallowing are associated with positive and negative z-scores, respectively. Change in negative and positive z-scores may be useful in evaluating brain activity of dysphagia patients during swallowing of sweetened and unsweetened food.

著者

Hisashi Suguro Osamu Takeichi Makoto Hayashi Teinosuke Okamura Akiko Hira Yoriyuki Hirano Bunnai Ogiso

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0092, (Released:2018-04-16)

参考文献数

25

被引用文献数

4

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Transparent epoxy resin root canal models were used to evaluate vertical condensation techniques for obturating lateral canals. The root canal model was configured with a straight main root canal and four right-angled lateral canals at 1.0 and 3.0 mm from the apex. Root canal obturation was performed with Thermafil, Obtura II, or NT condenser. Obturation volume in lateral canals was measured by three-dimensional microcomputed tomography, and one-way analysis of variance was used to analyze differences between groups. Lateral canals at 1.0 and 3.0 mm were uniformly filled by all obturation methods. Among the three obturation methods, Thermafil resulted in the highest obturation volumes for all lateral canals.

著者

Wakako Miyama Yasuki Uchida Mitsuru Motoyoshi Keiko Motozawa Moeko Kato Noriyoshi Shimizu

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

vol.60, no.1, pp.147-153, 2018 (Released:2018-03-24)

参考文献数

28

被引用文献数

3

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This study examined the relationship of vertical and horizontal changes in the alveolar bone crest with upper incisor movement after orthodontic treatment. Tooth movement was measured on lateral cephalograms. Vertical and horizontal changes in the median alveolar crest and distance from the cementoenamel junction and anterior nasal spine to the alveolar crest were measured with cone-beam computed tomography. The incisal edge moved distally, and the cervical point intruded significantly and moved distally. The median alveolar crest decreased by 3.80 ± 2.05 mm. The distance from the labial cementoenamel increased significantly, by 0.35 ± 0.38 mm. The vertical distance from the anterior nasal spine decreased significantly, and the alveolar crest moved distally. Vertical tooth movement was positively associated with change in the distance from the labial cementoenamel junction and inversely associated with vertical change in the distance from the anterior nasal spine on the labial and palatal sides. Lingual tooth movement was positively and negatively correlated with horizontal changes in the labial and palatal alveolar crest and vertical change in the palatal alveolar crest. The lingual movement of incisors was related to labial bone resorption. Greater lingual and extrusive movement of incisors led to a greater decrease in the alveolar bone crest.

著者

Kunihiko Sawada Toshihiko Amemiya Shigenori Hirai Yusuke Hayashi Toshihiro Suzuki Masahiko Honda Johnny Sisounthone Kunihito Matsumoto Kazuya Honda

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

vol.60, no.1, pp.137-141, 2018 (Released:2018-03-24)

参考文献数

23

被引用文献数

5

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We compared the diagnostic reliability of 3.0-T magnetic resonance imaging (MRI) for detection of osseous abnormalities of the temporomandibular joint (TMJ) with that of the gold standard, cone-beam computed tomography (CBCT). Fifty-six TMJs were imaged with CBCT and MRI, and images of condyles and fossae were independently assessed for the presence of osseous abnormalities. The accuracy, sensitivity, and specificity of 3.0-T MRI were 0.88, 1.0, and 0.73, respectively, in condyle evaluation and 0.91, 0.75, and 0.95 in fossa evaluation. The McNemar test showed no significant difference (P > 0.05) between MRI and CBCT in the evaluation of osseous abnormalities in condyles and fossae. The present results indicate that 3.0-T MRI is equal to CBCT in the diagnostic evaluation of osseous abnormalities of the mandibular condyle.

著者

Yoshimasa Takeuchi Hiroyasu Koizumi Mika Furuchi Yohei Sato Chikahiro Ohkubo Hideo Matsumura

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

vol.60, no.1, pp.1-7, 2018 (Released:2018-03-24)

参考文献数

32

被引用文献数

49

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Accurate impressions are essential in fabri-cating dental restorations and fixed dental prostheses. During the last decade, digital impression systems have improved substantially. This review discusses the accuracy of digital impression systems for fabrication of dental restorations and fixed dental prostheses. A literature search in PubMed was performed for the period from July 2010 through June 2017. The search keywords were Cerec, digital impression, direct digitalization, indirect digitalization, and intraoral scanner. Only relevant studies are summarized and discussed in this review. In general, the latest systems have considerably reduced the time required for impression making, and the accuracy and marginal fit of digital impression systems have recently improved. Restorations and fixed dental prostheses fabricated with currently available digital impression systems and intraoral scanners exhibit clinically acceptable ranges of marginal gap in both direct and indirect procedures.

著者

Ilda P. Ribeiro Joana M. Rodrigues Alexandra Mascarenhas Nadezda Kosyakova Francisco Caramelo Thomas Liehr Joana B. Melo Isabel M. Carreira

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.16-0811, (Released:2018-02-26)

参考文献数

54

被引用文献数

7

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Oral carcinoma develops from squamous epithelial cells by the acquisition of multiple (epi) genetic alterations that target different genes and molecular pathways. Herein, we performed a comprehensive genomic and epigenetic characterization of the HSC-3 cell line through karyotyping, multicolor fluorescence in situ hybridization, array comparative genomic hybridization, and methylation-specific multiplex ligation-dependent probe amplification. HSC-3 turned out to be a near-triploid cell line with a modal number of 61 chromosomes. Banding and molecular cytogenetic analyses revealed that nonrandom gains of chromosomal segments occurred more frequently than losses. Overall, gains of chromosome 1, 3q, 5p, 7p, 8q, 9q, 10, 11p, 11q13, 12, 13, 14, 17, 18p, 20, Yp, and Xq were observed. The largest region affected by copy number loss was observed at chromosome 18q. Several of the observed genomic imbalances and their mapped genes were already associated with oral carcinoma and/or adverse prognosis, invasion, and metastasis in cancer. The most common rearrangements observed were translocations in the centromeric/near-centromeric regions. RARB, ESR1, and CADM1 genes were methylated and showed copy number losses, whereas TP73 and GATA5 presented with methylation and copy number gains. Thus, the current study presents a comprehensive characterization of the HSC-3 cell line; the use of this cell line may contribute to enriching the resources available for oral cancer research, especially for the testing of therapeutic agents.

著者

Tetsuro Watase Kohei Shimizu Hiroki Komiya Kinuyo Ohara Koichi Iwata Bunnai Ogiso

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.16-0854, (Released:2018-02-26)

参考文献数

21

被引用文献数

9

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A study was conducted to evaluate the mechanisms underlying ectopic orofacial pain associated with tooth pulp inflammation in rats. We observed a significant decrease in the head withdrawal threshold (HWT) response to mechanical and heat stimuli applied to the ipsilateral facial skin upon application of complete Freund’s adjuvant (CFA) to the upper first molar (M1TP) in comparison to application of vehicle. A large number of trigeminal ganglion (TG) neurons showed transient receptor potential vanilloid 1 (TRPV1) immunoreactivity (IR), and some of them were retrogradely labeled with fluorogold injected into the facial skin. A large number of cells showing IR for glial fibrillary acidic protein (GFAP) were observed in the 2nd compared to the 1st or 3rd branch regions of the TG, and TG cells innervating the facial skin were also surrounded by GFAP-IR cells. After administration of TRPV1 antagonist into the facial skin of M1TP CFA-treated rats, the decrease of HWTs in response to mechanical and heat stimulation of the facial skin was significantly reversed. The present findings suggest that the excitability of TG neurons is enhanced upon tooth pulp inflammation, leading to overexpression of TRPV1 in TG neurons innervating the facial skin, and that satellite glial cells are also activated, resulting in the development of ectopic orofacial pain.

著者

Niina Tsurumachi Daisuke Akita Koichiro Kano Taro Matsumoto Taku Toriumi Tomohiko Kazama Yoshinao Oki Yoko Saito-Tamura Morio Tonogi Noriyoshi Shimizu Masaki Honda

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.16-0786, (Released:2018-02-26)

参考文献数

38

被引用文献数

4

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Dedifferentiated fat (DFAT) cells were isolated from mature adipocytes using the ceiling culture method. Recently, we successfully isolated DFAT cells from adipocytes with a relatively small size (<40 μm). DFAT cells have a higher osteogenic potential than that of medium adipocytes. Therefore, the objective of this study was to determine the optimal concentration of collagenase solution for isolating small adipocytes from human buccal fat pads (BFPs). Four concentrations of collagenase solution (0.01%, 0.02%, 0.1%, and 0.5%) were used, and their effectiveness was assessed by the number of small adipocytes and DFAT cells isolated. The total number of floating adipocytes that dissociated with 0.02% collagenase was 2.5 times of that dissociated with 0.1% collagenase. The number of floating adipocytes with a diameter of ≤29 μm that dissociated with 0.02% collagenase was thrice of those dissociated with 0.1% and 0.5% collagenase. The number of DFAT cells that dissociated with 0.02% collagenase was 1.5 times of that dissociated with 0.1% collagenase. In addition, DFAT cells that dissociated with 0.02% collagenase had a higher osteogenic differentiation potential than those that dissociated with 0.1% collagenase. These results suggest that 0.02% is the optimal collagenase concentration for isolating small adipocytes from BFPs.

著者

Akimasa Tsujimoto Wayne W. Barkmeier Toshiki Takamizawa Hidehiko Watanabe William W. Johnson Mark A. Latta Masashi Miyazaki

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.16-0815, (Released:2018-01-29)

参考文献数

40

被引用文献数

13

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This study evaluated the simulated localized wear of resin luting cements for universal adhesive systems using different curing modes. Five resin luting cements for universal adhesive systems were evaluated and subsequently subjected to wear challenge in a Leinfelder-Suzuki wear simulation device. Overall, 20 specimens from each resin luting cement were photo-cured for 40 s (dual-cure group), and 20 specimens of each material were not photo-cured (chemical-cure group). Simulated localized wear was generated using a stainless steel ball-bearing antagonist in water slurry of polymethylmethacrylate beads. In addition, scanning electron microscopy (SEM) observations of resin luting cements and wear facets were conducted. Significant differences in simulated wear and SEM observations of wear facets were evident among the materials in the dual- and chemical-cure groups. The simulated wear and SEM observations of wear facets of G-CEM LinkForce and Panavia V5 were not influenced by the curing mode. SEM observations of resin luting cements were material dependent. In most cases, dual curing appears to ensure greater wear resistance of resin luting cements than chemical curing alone. The wear resistance of some resin luting cements appears to be material dependent and is not influenced by the curing mode.

著者

安斉 碕 赤坂 巌 木下 孝明 石辺 尚明 友清 直 東 節男

出版者

Nihon University School of Dentistry

雑誌

The Journal of Nihon University School of Dentistry (ISSN:00290432)

巻号頁・発行日

vol.17, no.3, pp.66-72, 1975

被引用文献数

1

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From the experimental results it is made out that both PAC and ZPC, when soaked in water, show contraction and weight change to a great degree. That is, PAC shows contraction in dimension ranging from 0<I>i</I>20% to 0.28% 30 minutes after the beginning of mixing, while ZPC shows 0.24% of contraction. From the comparison of PAC and ZPC in the velocity of contraction in the initial stage of setting, it is presumed that PAC, as compared with ZPC is very slow in the velocity of setting reaction and unstable, for in the case of PAC, contraction continues for about 10-20 days, while ZPC becomes almost stable after 5 days. That is, it is presumed that contraction and weight decrease appearing in the initial stage of setting are closely related to the setting reaction. It is generally considered that the setting reaction of polyacrylic acid whose molecular formula is (CH<SUB>2</SUB>CHCOOH) n is due to the chelate bond between COOH of polyacrylic acid and Zn ion dissociated from ZnO, accompanied with dehydration, but it has not been confirmed as yet. But, at least, it can be presumed that the form of this bond would be -O-Zn-O-C-O- and Zn<OO>C-.<BR>Again, it is considered that as the result of chelate bond, water formed is gradually scattered outside from the set product of cement and consequently the weight decrease proceeds gradually. That is, it is presumed that the setting reaction due to chelate proceeds comparatively slow to continue for a long time. This is obvious from the fact of weight decrease, too. It is indeed a very interesting fact that in all cases except D, the weight change curves are rising from a day after, indicating the weight increase becoming larger gradually, and though there are some possible reasons for this fact such as the association between COOH group, the hydrophilic group existing in the molecule of polyacrylic acid, and H<SUB>2</SUB>O, water absorption due to the pores in the surface of set products and the transformation of zinc oxide ZnO into zinc hydroxide Zn(OH)<SUB>2</SUB>, still there remain points not yet clarified in this phenomenon. Again, as D, though the weight decrease can be seen up to 20 days after, from the fact that its weight increases slightly after 30 days, it can be presumed that in this case too, like in other cases, weight increase is ultimately continuing. But in this case, the setting reaction is considered_ very slow.<BR>On the other hand, it is a wonder that the dimensional change curves show contraction despite the weight increase. But from the fact that contraction becomes larger as time goes on, it can be presumed that the weight increase, unrelated to contraction caused by the setting reaction, is mainly due to the water absorption at the surface of set products.<BR>Anyway, it is obvious that PAC has contractivity and water absorbability. From this very fact it can be presumed that there is the possibility of the excellent adhesive strength of PAC being gradually deteriorated.<BR>Next, the dimensional and weight changes after 30 days in case the powder-liquid ratio is varied are as follows : in case the amount of powder is increased by 20% as compared with the standard consistency, the contraction rate decreases by approximately 50%, and the weight increase becomes very slow. Contrarily, in case the amount of powder is decreased by 20%, the results become completely reversed.<BR>The above fact suggests that in case the amount of powder is increased, ZnO showing a filler effect in the set products presumably suppresses the contraction. Again, the increase of the amount of powder means the relative decrease of polyacrylic acid, and it is understood that the weight change decreases because of the decrease of the unreacted acid and the decrease of the pore rate.<BR>At any rate, by making the amount of powder increased it becomes possible to make the dimensional and weight changes with the passage of time smallest, and undoubtedly the efficiency of cement can be