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頬粘膜咬傷に起因した頬部蜂窩織炎の1例
Get PDFapplication/pdfRecently, the development of various antibiotics and increasing awareness of oral hygiene have reduced the incidence of serious cellulitis of the cheek, including dental infections. However, some cases invoive serious disease throughout the mediastinal area in elderly patients and those with underlying diseases. This time, we report a case of cellulitis of the cheek due to a bite to the buccal mucosa. The patient was a 10–year–old male. The patient visited hospital and complained of swelling of the left cheek. At the first examination, diffuse redness and swelling accompanied by spontaneous pain and tenderness from the left cheek to surrounding area of the left orbit as well as trismus and swollen lymph nodes in the left submaxillary were noted. A crateriform traumatic ulcer with a diameter of 2.₅ cm and induration likely due to a bite of the left buccal mucosa and accompanied by tenderness were found. CT revealed a high–density region of the buccal fat layer in the left buccal soft tissues as well as extensive and significant swelling and inflammatory reaction. The infusion of antibiotics, draining the abscess through an incision, and the drainage procedure resulted in effective healing of the cellulitis 6 days after admission. Traumatic ulcer and cellulitis may recur due to bite. In addition, for the prevention of adverse habits including teeth grinding and clenching, as well as mental factors due to mental tension and frustration, it is very important to not only undergo dental or oral surgical treatments, but also to consult a psychotherapist or psychiatrist.journal articl
インプラント材としてのTi–6Al–4V 合金の変態温度と機械的性質の関係
Get PDFapplication/pdf要旨［目的］インプラント治療の普及に伴い，インプラント体の破折が数多く報告されるようになった。インプタント体の破折原因の一つには咬合関係を考えない不用意な埋植が挙げられるが，インプラント材料自体の強度不足も大きな原因である。現在インプラント材料としてはJIS第4 種純チ タンが主に使用されているが，耐力は500MPa，疲労強度は250MPa程度であるのに対し，チタン，アルミニウム，バナジウムの合金であるTi–6Al– 4V合金の耐力は800MPa，疲労強度は650MPa程 度と格段に大きく，破折しないインプラント材料 として注目されている。工業界ではTi–6Al–4V合 金の材質の向上を得るためには968℃で60分加熱し，溶体化処理を行い，ついで538℃で4時間加熱することが指示されている。大気中で加熱することは材料の酸化を誘発するために，これを回避 するにはガス雰囲気中での処理が必要になってくる。しかし，ガス雰囲気での熱処理には高額な装置を必要とする。したがって，大気雰囲気中での酸化を軽減するために加熱温度をできるだけ低くして，短時間での処理を検討する必要がある。Ti–6Al–4V合金は，500℃付近において変態が生じる。したがって，この温度を利用し，インプ ラント材料に，より適した材質に改良できる可能性がある。そこで，Ti–6Al–4V合金を450℃，500℃，550℃，600℃，650℃で加熱処理を行い，引張強さ，耐力，伸び，硬さ，金属組織について検討し，さらにX線回折により析出物についての検討を行った。［材料ならびに方法］実験には，Ti–6Al–4V合金（大同特殊鋼）直径5mm，長さ100mmを用い，以下の項目について検討した。1）変態温度の測定：加熱速度0.3℃/minの条件で1000℃までの熱膨張。2）熱処理：450℃，500℃，550℃，650℃，1時間500℃，0.5，1.0，1.5， 2 時間。3）引張強試験：引張り速度0.5mm/min，引張 強さ，耐力，伸びの測定。1．硬試験：試験片横断面の端から0.1mm，中間部の1.25mmと中心部のビッカース硬さ測定。2．金属成分の面分析：試験片横断面の中間部位，XMA（JEOL）使用。3．組織観察：試験片横断面の端，中間部，中心部，レーザー顕微鏡（オリンパス）使用。4．破断面の観察：引張試験後の破断面の観 察，電子顕微鏡（JEOL）使用。5．X線回折：直径8mmの棒材を厚さ1mmの板に流水下で削り出し，X回折装置 （JEOL）使用。［結果および考察］1．熱膨張試験より450℃から650℃の間に変態温 度が存在することが判明した。2．工業界の熱処理条件で処理したTi–6Al–4V合 金の引張強さは，処理前と比較して約12.7％増加，耐力は22％増加，硬さは46％増加したが，伸びは74％減少した。3．低温で熱処理した試験片の引張り強さは 500℃で処理した場合，処理前と比較して9.4％ の増加で，最大であった。耐力は500℃と550℃ はほとんど差がなく約24％の増加であった。硬さも500℃と550℃が約8.4％の増加であった。500℃の伸びの減少は，わずか11.3％であった。4．最も効果のあった500℃における加熱時間の影響は，60分加熱した試験片が引張り強さ，耐力，伸びにおいて，わずかに優れていた。5．X線回折の結果から，熱処理の効果はTi3Al規則格子の析出と，軟質なβ相の増大との兼ね合いによるものと考えられた。6．以上の結果から，Ti–6Al–4V合金を500℃で 60分加熱することにより，インプラント材料に適した性質を付与することができるものと考えられた。journal articl
Effect of substituting Trp for Leu at position 72 on the structure of Porphyromonas gingivalis superoxide dismutase
Get PDFapplication/pdfPorphyromonas gingivalis contains a single constitutive superoxide dismutase (SOD) that is active with either iron or manganese at the active site. The aim of this work was to evaluate the effect of the Leu ₇2 to Trp mutation on the structure of P. gingivalis SOD (Pg SOD) using lectrophoretic characterization. Leu ₇2, which is located near the active site metal, is substituted with Trp in aligned amino acid sequences of iron–containing SOD. The results of electrophoretic characterization and the expressed activity of mutant SOD suggest that mutant SOD have the same gross structure as wild–type SOD. We herein conclude that the integrity of Leu ₇2 is a necessary requisite for the metal–tolerant activity of Pg SOD.journal articl
Idiopathic macular hole displaced toward optic disc after vitrectomy with internal limiting membrane peeling.
Get PDFapplication/pdfPurpose: To compare the distance between the optic disc and the fovea (disc-to-fovea distance) before and after a successful closure of an idiopathic macular hole (MH) by pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling. Methods: This was a retrospective observational study of 37 eyes of 36 patients with a MH that had undergone PPV. The distance between the point of intersection of a blood vessel and the disc margin and the center of the opened or closed MH at 6 months after surgery was measured in the Spectralis HRA+OCT (Heidelberg Engineering, Germany) images. Results: The mean disc-to-fovea distance was significantly shorter postoperatively than preoperatively (3,783.7 ±308.5 μm and 3,914.5 ± 320.4 μm, respectively; P<0.0001). The distance in eyes with Stage 3 and 4 MH (n=22) was significantly greater than that in eyes with Stage 2 MH (136.7 ± 134.9 μm vs. 107.8 ± 107.8 μm, respectively; P=
0.012; n= 15). Conclusions: The significantly shorter postoperative disc-to-fovea distance in eyes with a closed MH especially Stage 3 and 4 MHs suggests that the fovea moves nasally after PPV with ILM peeling.journal articl
Mouse subcutaneous tissue reaction to calcium hydroxide-based.
Get PDFapplication/pdfMouse subcutaneous tissue reaction to an embedded calcium hydroxide-based root canal filling material was analyzed histopathologically. After the material was placed within the mouse dorsal subcutaneous tissues, we performed examinations using histopathological, histochemical and immunohistochemical techniques. Two weeks after embedment, the proliferation of granulation tissue had already begun to surround the calcification.
Most of the cells observed were macrophages. Likewise, multinucleated giant cells increased significantly. The multinucleated giant cells were observed as two types. In one, the centers of the giant cells were vacuoles, while in the others there were deeply stained calcifications with hematoxylin. Twelve weeks after embedment of the materials, further growth of multinucleated giants cells were sighted. Histochemically, von Kossa-stainpositive granules were observed within the macrophages and multinucleated giant cells as black fine granules. According to the TRAP stained specimens, the multinucleated giant cells especially reacted strongly at 4 weeks. However, the reaction became very weak at 12 weeks. CD68 immunohistochemical staining showed positive reactions in the cytoplasm of the proliferating macrophages and multinucleated giant cells. These results suggest that multinucleated giant cells are present in the surrounding tissues due to implantation of the calcium hydroxidebased root canal filling material, and that the presence of ACP in the cells is due to ingested calcium during active phagocytosis, which would disappear later on.journal articl