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Volume 61 (1994)
- Issue 4 Pages 485-
- Issue 3 Pages 413-
- Issue 2 Pages 197-
- Issue 1 Pages 1-
Volume 61, Issue 2
Displaying 1-17 of 17 articles from this issue
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—A Review of 30 Year Footsteps in Department of Dental Anesthesiology—Yasuya Kubota1994 Volume 61 Issue 2 Pages 197-206
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
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Masao Yamamura1994 Volume 61 Issue 2 Pages 207-220
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSNormal saline solution flushing of the inner mandible was done on twelve dogs, to confirm the effect of hemorrhagic infiltration that occurs in the fatty marrow.
Histological examinations were performed at 1 hour, 5 days, 10 days, 2 weeks, 1 month and 3 months.
Results:
1. Marrow extrusion occurred at approximately 1 atm (injection pressure) .
2. At 1 hour, marrow cavities located between the 2 injection holes with the exception of the extraction sites were filled with infiltrated blood cells. Fatty marrow was moderately replaced by the infiltrated blood cells in the extraction cavities and outer distal areas of the injection holes.
3. A sequence of histogenetic events occurred. The area of bone formation gradually expanded in the fibrous tissue area.
4. Expansion of the bone formation area was almost completed at 2 weeks. Most of the original marrow was transformed into thin trabeculaeforming areas, and hematopoiesis and sinusoidal capillaries formed in the new marrow. These conditions at 2 weeks were similarly maintained at 1 month.
5. At 3 months, the number of trabeculae, sinusoidal capillaries and hematopoietic area decreased, with the increase of adipose cells.
6. These results indicate that the area of fatty marrow where the hemorrhagic infiltration occurred was transformed into the bone formation area, and the marrow activates particularly high between the period of 2 weeks and 1 month.View full abstractDownload PDF (18004K) -
Pai Tsun Kuo1994 Volume 61 Issue 2 Pages 221-236
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThe focus of this study is aimed on the degree of occlusal bearing capability of the dense apatite implant in the maxilla and its histological alteration.
The implants were placed in the M2 and M2 areas of the adult monkeys. The vertical dimension was raised by the implants, the opposite M1 M2 M3 and M3 M2 M1 were splinted together with the connected crowns. At 1, 3 and 7 months after loading, the tissue surrounding the implants and opposing M1 M2 M3 was examined histologically with the following results :
1. The formed and newly compacted lamellae and woven bone were seen along the implant supporting the trabeculae and the compact bone that supports the implant and gradually getting thicker until the third month.
2. Realignment and remodelling of the trabeculae and compact bone continously progressed from 3 months onward.
3. Bone formation and bone remodelling were also observed to have progressed widely towards the neighboring teeth, and bone remodelling in the maxillary sutures similarly occurred.
4. The splinted opposite teeth intruded gradually during the experiment.
5. In some implants, few fracture areas close to the surface were observed in the bone that was in contact with the implant.View full abstractDownload PDF (18517K) -
Takahide Komori, Tsuyoshi Takato, Keiko Yokoyama, Sadao Tomioka, Shige ...1994 Volume 61 Issue 2 Pages 237-241
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThe patients referred from our hospital at the Department of Oral Surgery, University of Tokyo, during the two years from January 1990 to December 1991 were analyzed statistically. The results were as follows :
1. Our subjects were 1, 152 patients (24.2% of first-time patients), 540 males and 612 females.
2. Concerning age distribution, the majority was in their forties, fifties and sixties.
3. More patients were from internal medicine, ENT clinic, plastic surgery and cardiothoracic surgery.
4. On the number of patients categorized by disease at other departments, the largest number was cardiovascular disease.
5. On the number of patients categorized by disease at our department, the majority were dental diseases (dental caries, marginal periodontitis and missing teeth) .View full abstractDownload PDF (465K) -
Hidekazu Takahashi, Hideo Nakamura, Naohiko Iwasaki, Naohisa Morita, N ...1994 Volume 61 Issue 2 Pages 242-249
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSRecently, several new products of investments for “quick heating” have been put on the Japanese market. The total casting procedure time for this quick heating method involves only one hour ; 30-minutes waiting after the start of mixing before placing the mold directly into the 700t furnace and 30-minutes heating in the furnace. The purpose of this study was to evaluate two variables effecting casting accuracy using these new investments.
The effect of thickness of the casting liner inside the casting ring and the effect of waiting time before placing the mold into the 700°C furnace were evaluated. A stainless-steel die with a convergence angle of 8° was employed. Marginal discrepancies of the crown between the wax patterns and castings were measured.
The size of the cast crown became larger when the thickness of the ring liner was thick and when the waiting time before placing the mold into the furnace was long. These results suggest that these new investments have the advantage of providing sound castings using short-time casting procedures. However, it is necessary to pay careful attention to the casting conditions for obtaining reproducible castings.View full abstractDownload PDF (2351K) -
Akihiko Morikawa1994 Volume 61 Issue 2 Pages 250-274
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThe purpose of this investigation is to detect vertically and buccolingually the occlusal force on the lower first molar in function and to make a two-dimensional vector analysis concerning the occlusal force.
The subminiature occlusal force measuring apparatus, which makes use of two-dimention load cell, is developed with the appratus equipped in the corona on the natural root of the tooth, each occlusal force on the single tooth is detected, when three subjects clench and masticate four kinds of test-foods.
Conclusions are as follows:
1. Average occlusal force exerts 3.6kgf during light clenching and 25.7kgf during heavy clenching. The average direction of occlusal force against the tooth axis exerts 21.2° during light clenching and 19.5° during heavy clenching.
2. The masticatory force intensity exerts the differences in the phases of mastication and the properties of the test-foods. The maximal masticatory force is 33.1-7.9kgf during the initial phase and 9.6-5.1kgf during the last phase of mastication.
3. Average direction of masticatory force against the tooth axis is 19.9° during the initial phase and 27.8° during the last phase of mastication.
4. The operating period of masticatory force per cycle is 0.331 second on the average during the process of mastication. The longest period is in the initial phase of mastication, and as the mastication proceed it gradually decreases.View full abstractDownload PDF (6466K) -
Tomohiko Yaka1994 Volume 61 Issue 2 Pages 275-289
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThe effects of different occlusal position on the masticatory muscle function were investigated on 5 subjects.
Two types of maxillary stabilization splints were fabricated in order to change the occlusal position. One type of the splints was to increase the occlusal height and the other was to shift the occlusal position laterally.
The EMG activities of the masseter (M) and the anterior and posterior temporal muscles (AT, PT) were measured in various occlusal positions at 50% of maximal voluntary activity of the M and AT.
The results were as follows:
1. When the occlusal height was increased,
1) The activity of the PT decreased in most subjects.
2) Asymmetry index (AI) of each tested muscle did not always indicate a similar value.
2. When the occlusal position was shifted laterally,
1) The activities of the ipsilateral AT and PT were higher than those of the contralateral side.
2) The AT of the AT and the PT changed gradually when the occlusal height was large while they changed greatly near the intercuspal position (IP) when the occlusal height was smaller. Therefore, the symmetry of the temporal muscle activity was thought to be influenced sensitively by the lateral shift of jaw position near the IP.View full abstractDownload PDF (4822K) -
Yuichi Hirayama1994 Volume 61 Issue 2 Pages 290-308
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThe purpose of this study is to examine the diagnostic accuracy in the detection of jaw lesions with computed panoramic radiography and to find optimal parameters for every diagnostic purpose. A phantom of an artificial mandibular bone was devised, and radiolucent and radiopaque jaw lesions were simulated by a wedge-shaped cavity.
Panoramic radiographies were taken by varying the position of the phantom and the parameters of computed radiography (CR) .
The results were as follows:
1. Detectability decreased more abruptly with CR than with conventional radiography with the increase of the distance from the focal trough.
2. The optimal relative gamma value (GA) of CR for the radiolucent lesions (air) was ; 1.2 for gradationally enhanced (L) images and 1.0 for frequency enhanced (R) images. The detectavility was not influenced with the changes in the spatial frequency areas (RE) .
3. The optimal parameters for the radiolucent lesions (water) were ; GA= 1.2, RE=0.2 -0.5, frequency enhancement ranks (RN) =1 for the L images, and GA =1.0-1.2, RN = 3-5 for the R images.
4. The optimal parameters for the radiopaque lesions (50% CaCl2 solution) were ; GA= 1.2 -1.6 for the L images and GA= 1.6, RE = 5.0, for the R images.
5. The clinical images with these optimal parameters were generally recognized as better than those with non-optimum parameters.View full abstractDownload PDF (10004K) -
Yutaka Hasegawa1994 Volume 61 Issue 2 Pages 309-328
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSEffect of 6 types of mouthguards on the vibratory characteristics of the human dry mandible was investigated by means of modal analysis with the impact test method. In this study, 20 test points were established on the mandible and the modal shape and damping ratio of the vibration of the mandible itself and the mandible each attached with a mouthguard were analyzed by using the FFT analyzer (CF-6400) and personal computer (PC-9801FA) with a modal analyzing software (VIBRANT-PC) .
The results were as follows :
1. With regard to the modal shape, there was almost no difference among the mandibles and each mandible with 6 types of mouthguard.
2. With regard to the damping ratio, there was a significant difference between the mandible itself and mandible with each mouthguard. And the effect of the mandible with each mouthguard on the damping ratio was different.View full abstractDownload PDF (6891K) -
Bin Zhong1994 Volume 61 Issue 2 Pages 329-352
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThe purpose of this study was to investigate the structures and functions of the gingival fibers extending in the mesiodistal direction (mesiodistal fibers) in the human gingiva of the upper molar region. They were observed by light and scanning electron microscopes.
The findings are as follows:
1. There is a large number of mesiodistal fibers in the buccal gingiva of the upper molar region.
2. In addition to the factor of the space, there exists a close relation between the development of the mesiodistal fibers of the buccal gingiva and the function in its region.
3. The mesiodistal fibers are made up of primary and secondary fiber bundles.
4. The bundles of the mesiodistal fibers compose the three dimensional network and are twisted.View full abstractDownload PDF (24569K) -
—Structures and Functions of Dentogingival Fibers—Shi An1994 Volume 61 Issue 2 Pages 353-374
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSIt was the purpose of this paper to observe the structural features and discuss the functions of the dentogingival fibers in the human gingiva of the upper premolar region. They were observed by a light microscope.
The results are as follows:
1. There is a large number of dentogingival fibers in the lingual gingiva of the upper premolar region.
2. Ten to fifteen dentogingival fibers form a bundle. And the bundle is twisted.
3. The dentogingival fibers increase in proportion to the thickening of the gingiva, and it seems that the dentogingival fibers is one of the main functional fibers.
4. Enlargement of the epithelial attachment and the increase of the fibers in the papillae accompany the cell differentiation of the epithelial basal cells.
5. It is observed that the tension of the dentogingival fibers extend widely to the epithelial cells of the stratum spinosum.View full abstractDownload PDF (18130K) -
Masashi Sato1994 Volume 61 Issue 2 Pages 375-397
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSThis study was designed to estimate objectively the hardness of the oral mucosa which is not directly supported by the bone. A new, easy-to-use hardness-measurement apparatus for measuring the oral mucosa free of the underlining bone was manufactured for trial use. The hardness values of the oral mucosa were evaluated quantitatively, resulting from pressing 2 mm into the mucosa with a 2-mm-in-diameter hand-held probe coupled to the hardness-measurement apparatus. Experimental and clinical confirmation was made that practical errors in hardness values are quite permissible when using this apparatus. This fool-proof method was further examined in extensive clinical application.
The normal mucous membrane of the tongue, the floor of the mouth, and the cheek respectively measure 4.45, 4.33, and 2.96 gf on average with this apparatus. Examining 26 cases of squamous cell carcinoma on the tongue, the floor of the mouth or the buccal mucosa (16.87-80.32 gf) revealed that the value of measurement of squamous cell carcinoma was as much as 2.31-19.06 times in comparison with the normal mucous membrane. Squamous cell carcinomas were ascertained to be statistically harder than the normal mucosa (p<0.001) and the tumor margins may be far more precisely clarified with this apparatus than with the human finger alone.View full abstractDownload PDF (11646K) -
[in Japanese], [in Japanese]1994 Volume 61 Issue 2 Pages 398
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]1994 Volume 61 Issue 2 Pages 399
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...1994 Volume 61 Issue 2 Pages 400
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
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[in Japanese], [in Japanese], [in Japanese]1994 Volume 61 Issue 2 Pages 401
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSDownload PDF (1754K) -
[in Japanese], [in Japanese], [in Japanese]1994 Volume 61 Issue 2 Pages 402
Published: June 30, 1994
Released on J-STAGE: October 08, 2010
JOURNAL FREE ACCESSDownload PDF (1991K)
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