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水酸化カルシウム系糊剤根管充填材に対する組織反応
Get PDFapplication/pdfWe injected five kinds of calcium hydroxide pastes subcutaneously into the dorsal area of 6-week-old anesthetized male ddY mice. Two days, 1 week and 3 weeks after injection, the removed tissue surrounding the injection site was examined histopathologically from mice in each group. The following results were observed: necrotic tissue with calcification in some parts, and granulation tissue proliferation including macrophages and foreign body giant cells, in each group. These changes were restricted to the injection sites in all groups, and there was no damage around the tissue. The tissue reactions to the five kinds of examined pastes were nearly the same.journal articl
歯科用セメントの曲げ強さにおけるサーマルサイクルの影響
Get PDFapplication/pdfVarious types of cementing materials were subjected to thermocycling (between 4℃ and 60℃ for 1,000, 3,000, and 10,000 cycles) and storage in 37℃ in water for equivalent duration to the total thermocycling time. These samples were then subjected to bend strength and fracture strain tests. Fractographic studies were also conducted on fractured surafecs. The main results obtained are as follows; 1. Bend strengths of LC, HG, EC and FL sample groups increased even after 10,000-cycled thermocycling treatment. On the other hand, LM sample group showed a decrease in bend strengths. 2. Bend strengths of LC, HG, EC, FL and LM sample groups which were stored in 37℃ water for 375 hours were higher than those of the 24-hours storage in 37℃ water. 3. Fracture strain of LC, HG, EC, FL and LM sample groups thermocycled for 10,000 cycles decreased. Similar result was obtained for same sample groups which were stored in 37℃ water for 375 hours. 4. With fractured surfaces of LC, HG, and EC sample groups, spherical cavities were observed, suggesting that reaction gas was entrapped.journal articl
歯冠幅径の削減を行ったアーチレングンスティスクレパンシー解決法
Get PDFapplication/pdfIt is very important to resolve the imbalance between tooth size and alveolar bone length, that is the dental arch length discrepancy, when we make a treatment plan for an orthodontic patient. This imbalance needs the same amount of space on the dental arch to resolve the arch length discrepancy. Orthodontists usually apply four premolar extraction, dental arch expansion and molar distalization to resolve this problem. As another orthodontic method tooth width reduction to resolve the discrepancy has been developed by Jack Sheridan since 1985. In his report, this method reduced the percentage of the extraction case. The purpose of this study was to present an orthodontic case treated with this method, to introduce how to calculate the width of dental enamel using dental X ray film and how to reduce the enamel, and finally to clarify the importance of clinical usage of this method. As the result, it was possible to calculate correctly the enamel width using dental X ray film and personal computer digital processing methods, and to apply the width for enamel reduction clinically. This enamel reduction method was understood to be an available method for resolving the moderate imbalance of tooth size discrepancy easily and quickly, as well as comparing expansion of dental arch or distalization of molars.journal articl
Difference in treatment outcome of British and Japanese surgical class III patients associated with mandibular setback
Get PDFapplication/pdfThe purpose of this clinical research was to examine the racial differences in skeletal morphology of skeletal Class III abnormalities and in the ortho-surgical treatment outcome of Class III malocclusion associated with mandibular setback sagittal osteotomy between Japanese and British Caucasian female adult Class III patients. The sample consisted of 35 Class III Japanese female surgical subjects in MDU Hospital and 30 Class III British subjects (23 female and 7 male). The operative procedure was solely a backward sliding sagittal split osteotomy with a wire fixation. True skeletal open bite cases associated with high mandibular plane angle were excluded. The original skeletal differences in Japanese and British Caucasian Class III subjects showed a significant difference in the length of the anterior cranial base (S-N) (p<0.001). The Japanese Class III subjects showed a significant difference in the parameters of U 1-UR and L 1-LR to palatal plane and Go-Me to palatal plane (p<0.001), and in the axis of maxillary incisor to S-N (p<0.01) and S-N-L 1 (p<0.05). At post-retention (1 year after op.), Go-Me to ANS-PNS and the length of Go to the palatal plane and Ar-Go (ramus height) related to the vertical position of point Go showed a larger difference (from p<0.05, 0.01 to 0.001). The Japanese surgical cases showed a more vertical problem with the increased mandibular plane angle compared to the British Caucasians.journal articl
キトサンを結合体とした自己硬化型骨補填材の研究
Get PDFapplication/pdfA self-curing type of bone filling material has been developed by mixing chitosan solution and admixed powder. The chitosan solution was prepared by dissolving 85% de-acetyl chitosan and 99% deacetyl chitosan with organic acids, and the powder was a mixture of hydroxyapatite particles, CaO powder, and ZnO powder. The bone filling materials were compressed to form samples for compression tests. The Ca ions, P ions, Zn ions and pH value were measured. The main findings were as follows; 1. The compression strength of bone filling materials using 85% de-acetyl chitosan showed a maximum value of about 13 MPa at 1 day after immersion in physiological saline solution, followed by a continuous decrease down to 2 MPa. On the other hand, the bone filling material prepared with 99% de-acetyl chitosan did not show a remarkable decrease in compressive strength, however, it exhibited a continuous but smaller decrease by immersion time than the filling material prepored with 85% de-acetyl chitosan, because 85% de-acetyl chitosan gel could be more easily dissolved by 99% de-acetyl chitosan. 2. The changes in pH value of both 85% and 99% de-acetyl chitosan bone filling materials showed minimum values at 1 day after immersion, followed by a continuous increase with time, and the pH value of bone filling material containing 99% de-acetyl chitosan was higher than that with 85% de-acetyl chitosan material. 3. The dissolved Ca ions from the bone filling material with 85% de-acetyl chitosan reached its maximum at 28 days and minimum at 56 days after the immersion into physiological solution. The dissolved Ca ions from the bone filling material containing 99% de-acetyl chitosan exhibited its maximum at 1 day and its minimum at 28 days after the immersion, but there was no difference between these two types of materials. 4. The dissolved P ions from bone filling materials containing 85% and 99% de-acetyl chitosan had similar trends of continuous increase with time, and there was no difference between the two materials. 5. With regard to the dissolved Zn ions, the bone filling material made using 99% de-acetyl chitosan showed smaller values than that made with 85% de-acetyl chitosan, except at 56 days after the immersion.journal articl
歯周病原菌Porphyromonas gingivalisと関連菌のタンパク分解酵素と鉄獲得機構
Get PDFapplication/pdfPorphyromonas gingivalis, an oral indigenous bacterial species has been implicated in the pathogenesis of adult human periodontitis. This microorganism lacks, however, sydero-phore system which serves the purpose of iron uptake function in bacteria. Therefore, an alternative mechanism responsible for iron uptake system must be found in P. gingivalis. In this review, the present knowledge of acquisition of iron source and possible role of endo-geneous proteolytic enzymes in the iron uptake system in periodontopathogens including P. gingivalis and its related species.journal articl