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Biomedical subjects

A Muramatsu

Publications and source records attributed to A Muramatsu.

At least 19 recordsLinked to original sources
PubMed1979

[Studies on the performance of the dental air turbine handpieces. (Part 1). Air pressure and bur length to be influenced over the rotational performance of the air bearing type handpieces (author's transl)].

Air turbine handpieces are used as the dental cutting instruments for the clinical use and many appliances. But, there are no studies on the performance of air turbine handpieces. So, this paper shows the rotational performance of air turbine handpieces which are influenced over the supplying air pressure and cutting bur length. Experimentally used air turbine handpieces is air bearing type and it's set up air pressure to be supplied is 3.5 kg/cm2. So, in this experiments, the range of air pressure is 1.8 approximately 3.5 kg/cm2, which is established five stages. And the bur length of the rotational parts is 5 approximately 9 mm with five steps. As the results, the rotational performance of air handpieces are influenced over these factors of the air pressure and the bur length. And air pressure to be supplied are influenced to be not only over the rotational speed but the load for the putting a stop to the revolutions.

Air Pressure↗
PubMed1978

[(author's transl)].

Explore the source record for details and available documents.

Dental Cavity Preparation↗
PubMed1978

[Some studies on the ability appreciation of dental handpieces (author's transl)].

Dental handpieces are usually used for cutting teeth instruments of dental treatments. But as ability appreciation of cutting instruments are widely influenced with cutting tools and then these studies have scarcely been reported until now. This paper shows the one method of the ability appreciation of handpieces which are used for test bur as the cutting tools. Test apparatus used for ability appreciation are manufactured for trial as the same way as the dental treatments and experiments of handpiece are carried out. Handpiece test specimens are standard type (air bearing type) made by own country as basic characteristics and then compering with the ability of the type differences, standard, miniature, supertorque and air bearing type made by foreign country are experimented. These results of tests are examined the influence of service air pressure and load speed to be bases on the relation between push load revolution of test burs. And then equivalent efficiency of the works of handpieces are discussed for the experimental results of these characteristics.

Air↗
PubMed1978

[Studies on the cutting ability of dental diamond points--the trial manufacture of the cutting test apparatus (author's transl)].

Diamond points and tungstencarbite burs are used as the dental cutting tools for many appliance accordingly with the many purpose of used positions. Notwithstanding that the dental cutting tools have been usually applied for many purpose of dental treatment, the paper on these studies have scarcely been reported. In this studies the test of dental cutting tools curried out using the diamond points and examined these characteristics. As the problems on the cutting tests are the push load of cutting tools and the cutting quantities. This studies tried to make the test apparatus for the cutting test of dental diamond points considering to dental treatments. The glass plates used for photograph are used for cutting materials supposing to the enamel properties of teeth and the cutting tests put into practice for the types of diamond points with different diameter. The cutting characteristics of the diamond points are examined with the using of the test results and are appreciated with the considering to the test apparatus.

Dental High-Speed Equipment↗
PubMed1977

Familial medullary carcinoma of the thyroid through 3 generations.

A family with high genetic penetrance of medullary carcinoma of the thyroid was reported. Seven proven (6 patients and one autopsy case) and 2 probable cases of medullary carcinoma were present in 25 members through 3 generations. An endogemy had intervened in the prior generation of these cases. Preliminary results in clinicopathological examinations of 7 proven cases were as follows; clinically, all of the cases showed B type blood group. Glycosuria was found in 2 cases, and diarrhea in one case. Serum thyrocalcitonin being estimated in two cases showed high levels. The autopsy cases coexisted with medullary carcinoma of the thyroid and pheochromocytoma of the right adrenal. Pathologically, the majority of tumors occurred in both thyroid lobes, and were present from the middle to upper portion of the thyroid. The tumor showed a variety of histological features even in the same tumor. In the tumor cell, numerous membrane-limited granules were seen with an electron microscope. Amyloid was demonstrated only in the tumor tissue.

ABO Blood-Group System↗
PubMed1976

[Studies on the strength and the cutting performance of dental canal reamer. (I) Strength properties of raw materials of dental canal reamer and these standard (author's transl)].

Pulp canal reamers have been widely used for dental treatments of the root of teeth. The work's accuracy and cutting capability of these instruments are treated by the standarization of JIS and ADA etc. Especially Japanese industrial standarization (JIS) treated the dimensions of the configurations, materials and ability of dental canal reamers. But there is no report of the studies on the work and fracture strength of these dental instruments. So, this paper makes a report on these problems, which are the measurements of the diameter of the bite tips, are concerned the strength of the raw materials of dental canal reamers and are compared with the standarization (JIS) of these instruments. Test of the raw materials of reamers are tensile properties and are measured the strength and elasticity of these materials. And phase of fracture of these materials are investigated with the scanning electric microscope and the fracture modes are compared with the tensile strength properties.

Dental Instruments↗
PubMed1976

[Studies on the strength and the cutting performance of dental canal reamer. (II). Torsional strength and tip diameter of dental canal reamers (author's transl)].

Strength of pulp canal reamers are important problems for cutting treatments of the root of tooth at the dental regions. Reamers have been used as cutting tools by the twisting movements, and then, fracture of reamers are especially caused by the shearing stress at the bite tips. So, this paper treated the shear strength of dental canal reamers, which are torsional strength and twisting rigidity of these cutting instruments. And we made the torsional apparatus for cutting and twisting tests, and tested the torsional strength of raw materials and pulp canal reamers. Type of reamer's configuration are treated by Japanese industrial standard (JIS) and these properties are readjusted with dimensions of diameter of reamers. Shear strength of reamers are 120 approximately 140 kg/mm2 and strength of straight bar with taper are about two times of that of reamers which are about 40 kg/mm2 (except reamer's number 1, 2). Scattering of value of strength and torsional angle of these reamers are examined and showed the range of scattering of these properties. Effectiveness of torsional angle on the fracture properties are considered on the clinical treatments and treated the safety of fracture of these reamers.

Dental Instruments↗
PubMed1976

[Studies on the strength and the cutting performance of dental canal reamer. (III) Cutting performance and torsional fracture (author's transl)].

Characteristics of cutting torque and fracture strength of pulp canal reamers are important problems as for the severity used at many of dental cutting tools. And it is the most difficult problems that reamers are cutting tools to be used for magnification of root canals. So, this paper makes a report on the measurements of reamer's section and dimension of the under hole, which are required for cutting test, and on the safety of characteristics of dental canal reamers. Diameter of under hole are determined by the relationship of reamer's section. And these results of measurements are compared with the Japanese Industrial Standard values and we discussed the probabilities of the clearance of these dimensions. Cutting torque of reamers are measured with twisting test machine of our making. Concerning the safety of fractures, we apply the theoretical analysis for the fracture to torque of bite tips and estimated the fracture torque of cutting section of reamers. And probablity of twisting fracture of reamers are existed about from one half to one-fifth values for the dental reamers of practical used.

Dental Instruments↗
PubMed1976

[Mechanical studies on the dental bridges. (XI) Studies on the apportionment loads to be affected by the supporting conditions of two abutment teeth (author's transl)].

Abutment teeth have been treated as the elastic behavior at the supported conditions and apportionment loads are depended upon the elastic properties of the pontics and abutment teeth. So, this paper shows the apportionment loads of dental bridges and the dependence of the elastic constants of abutment teeth. Abutment teeth are rotated and sinked with digestive power on the pontics. So, the elastic constants of abutment teeth are given with k and K, which k, K are the sinked and rotated coefficients, which are expressed the elastic properties of these abutment teeth. Apportionment loads to be connected with the flexural rigidity of the pontics are calculated for two numerical examples (for the values of 3.6 x 10(3) kg-mm2 and 3.6 x 10(8) kg-mm2 of the concentrated and distributed loads).

Dental Abutments↗
PubMed1976

[Mechanical studies on the dental bridges. (XII) theoretical development of load analysis on the abutment teeth (author's transl)].

Load analysis of abutment teeth have been treated as the two abutment teeth problems, which are subjected on the concentrated and distributed loading conditions. And we considered the numerical analysis for these problems. Abutment teeth are supported with elastic condition, which are normal deflection and rotational movements. This paper shows the theoretical development of the load analysis of these problems. These pontics are supported with the numberless abutment teeth. Example problems are shown the concentrated and distributed load at the one span of these pontics. Therefore, we do not show the numerical examples of these problems but theoretical development of apportionment loads of these abutment teeth are represented to be concerned for many problems in this paper.

Dental Abutments↗
PubMed1975

Senile degenerative brain lesions and dementia.

In a study of senile degenerative lesions-including Alzheimer's neurofibrillary changes, senile plaques and amyloid angiopathy-the hippocampal area of the brain was examined by thioflavine T fluorescence microscopy in 146 consecutive autopsy patients over the age of 49. The incidence and quantity of neurofibrillary changes and senile plaques rose with age, and an approximate positive correlation in quantity was noted among the three kinds of degenerative change. The quantity of neurofibrillary lesions and senile plaques was significantly different between the demented and non-demented patients, but not between the severely and less severly demented patients. The cause of dementia was studied retrospectively, based on the extent of morphologic changes in the brain, thus classifying dementia into three types: degenerative, vascular, and mixed. Clinically, the mixed type resembled the vascular type with regard to major neurologic signs, and there was some similarity to the degenerative type with regard to mental features.

Aged↗