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矯正力の正しい臨床応用のために
Get PDFapplication/pdfAt the present time, there are many forms of multibanded appliances in common use in our daily orthodontic practice. With this mechanism all the teeth can be moved in every direction, even the root movement being possible. Though success in orthodontic treatment depends on the efficiency of the appliances, the knowledge of basic biological problems is so much important to avoid the unfavorable reactions of teeth and alveolar bone which may be caused by malmanipulation. When the teeth have been subjected to excessive forces without biological considerations of the orthodontic procedure, there are marked root resorption, necrosis oftoothinvesting structures, pain and loosened teeth. From the stand point of clinical orthodontist, we dealt with reconsiderations of "What kind of force causes less tissue damage?" in this article.journal articl
Additional Properties of a Bacteriocin-like Agent (Acnecin) of Propionibacterium acnes
Get PDFapplication/pdfPurified acnecin showed that it exerted bacteriostatic activity against susceptible indicator cells without adsorption on the cells, and its activity lost by treatment with Na-periodate or lysozyme. Acnecin inhibited also production of an extracellular enzyme (Ribonuclease) of acnecin-susceptible strain.journal articl
下顎第三大臼歯の植立状況による同歯牙および第2大臼歯の齲蝕発現部位のX線学的考察
Get PDFapplication/pdfUsing 585 X-ray films taken for the treatment in the hospital of Matsumoto Dental College during one year between May, 1978 and April, 1979, caries regions of mandibular second and third molars were investigated with the relation to the plantations of the third molars. 1) The plantation of mandibular third molars against the second molars can be classified six types, disto-angular type, vertical type, slightly mesio-angular type, intense mesio-angular type, horizontal type and impacted type. 2) As the result of this investigation, vertical type was most common, 37%, horizontal type 21%, intense mesio-angular type 16%, slightly mesio-angular type 8%. Impacted type was relatively common, 11%, conversely disto-angular type was rare, 7%. 3) Intense mesio-angular type was more common in the male than in the female and horizontal type was similarly, conversely vertical type was more common in the female. 4) The frequency of the caries from distal contact point on mandibular second molars was 40% in the C type, i. e. mandibular third molars erupted completely and slightly mesio-angular. And in the D type, i. e. mandibular third molars erupted incompletely and intense mesio-angular, 50%. These showed very high rate. 5) Frequency of the caries from mesial contact point on mandibular third molars was 48% in the C type, and 38% in the D type. These showed very high rate. 6) No relations of caries region of mandibular second and third molar were observed in the A type and B type. In the C type, distal surface caries on mandibular second molars and mesial surface caries, mesio-occlusal surface caries, mesio-disto-occlusal surface caries on third molars were often seen. The D type showed distal surface caries on mandibular second molars and occlusal surface caries on third molars. In the E type occulusal surface caries and disto-occlusal surface caries on mandibular third molars were also observed.journal articl
フッ素分離における拡散条件の検討
Get PDFapplication/pdfSeparation is necessary to the determination of fluoride in most types of biological samples except bone and teeth. At present, the diffusion procedures have widely used because many samples can be dealt with at one time and high temperatures are not required. In 1967 D. R. Taves discovered that diffusion of fluoride was greatly accelerated by the presence of silicone grease containing acidified sample and led to the development of a new procedure for rapid diffusion of fluoride at room temperature, using hexamethyldisiloxane (HMDS). Consequently, we studied several conditions concerning acidified samples containing HMDS in diffusion. Diffusion bottle on the market (Tupper Ware Minicup) was used and filter paper (12×25 mm) was hanged for trapping of fluoride. The results of several experiments are summarrized as follows: 1. As trapping solution 0.5 M sodium hydroxide was effective in fluoride recovery rate compared with 0.5 M magnesium succinate. 2. The concentration of perchloric acid for evolution of fluoride ranging 2.7 to 2.7×10^M makes no difference in recovery of fluoride. 3. HMDS in sample solution shortened the diffusion time. In addition to that, shaking of diffusion bottle shortened the diffusion time up to 30 to 60 minutes at room temperature.journal articl
頭部X線規格写真ならびにパノラマX線写真上でみられる歯の異常について
Get PDFapplication/pdfOrthodontists take lateral head plates, panoramic radiographs and dental X-rays for treatment and diagnosis, almost as a routine. So they have a big chance to find the abnormal development of hard tissues on X-rays. But, there is little material concerning pathosis or teeth abnormalities observed on the lateral cephalometric and panoramic radiographs. The purpose of this paper is to review and classify the abnormalities of teeth noted on the X-ray films of oral regions.journal articl
歯根透明象牙質のMicroradiographyとElectron-microscopy,第2報 とくに波長分散形とエネルギー分散形との比較観察
Get PDFapplication/pdfUsing the same materials as of the first report, transparent root dentin was studied by means of microradiography, electron-microscopy both of transmission and scanning, field limited diffraction, wavelength dispersive x-ray spectroscopy and energy dispersive x-ray analysis. Results are as follows: 1. The transmission and scanning electron-microscopies revealed that the crystals of calcium salt deposited in the dentinal tubules (Figs. 2, 3, 5) were much smaller than that of intertubular dentin which were in big needle-like shape (Figs. 2-4). 2. Although the crystals of intertubular dentin arranged in some order due to collagen fibers (Figs. 3, 4), the ones in the dentinal tubules put in disorder (Figs. 3,5). 3. The quantitative analysis by the energy dispersive x-ray analyser showed that the emission counts of Ca and P were somewhat higher in the depositions in the dentinal tubules than in the intertubular dentin. However it was noticed that quantitative differences between the two were changed markedly in the different sites examined (Table 1). 4. By the elementary analysis with the wavelength dispersive x-ray spectroscope, it was observed that the depositions in the dentinal tubules contained the elements of Ca, P, Mg, Na, S, O and that the counts of Ca, P and Mg were 10% higher in the depositions than in the intertubular dentin (Table 2).journal articl