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Volume 58 (1991)
- Issue 4 Pages 643-
- Issue 3 Pages 591-
- Issue 2 Pages 355-
- Issue 1 Pages 1-
Volume 58, Issue 2
Displaying 1-16 of 16 articles from this issue
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Challenge to Angle's orthodonticsFujio Miura1991 Volume 58 Issue 2 Pages 355-362
Published: 1991
Released on J-STAGE: October 27, 2010
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Tadao Iida1991 Volume 58 Issue 2 Pages 363-379
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSThe purpose of this study was to clarify the interrelation of the tooth crown diameters using statistical methods.
The material consisted of 414 dental casts from orthodontic patients in the Japanese female.
The mesiodistal diameters of all permanent teeth on the left side were measured, excluding the third molars. These values were examined by correlation coefficient matrix and multivariate analyses such as multiple regression, principal component and canonical correlation, etc..
The results were as follows:
1) The tooth crown diameters showed a strong intercorrelation within each jaw and between both jaws.
2) When the incisors and the canine were large in size, the premolars and the molars tended to be small.
3) When the incisors and the molars were large in size, the canine and the premolars tended to be small.
4) When the incisors and the premolars were large in size, the canine and the molars tended to be small.
5) All of the teeth except the upper lateral incisor were classified according to size into the four groups of incisors, canines, premolars and molars.
6) The dentition with small teeth tended to show a spaced arch.View full abstractDownload PDF (3003K) -
Tetsuya Yoda1991 Volume 58 Issue 2 Pages 380-402
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSPerforations of the temporomandibular joints (TMJs) disc were made in the rabbits and repaired with autogenous dermal grafts. The healing process was investigated histologically Twenty-one rabbits (forty-two TMJs) were divided into 3 experimental groups.
Group 1. Six TMJs in which the superior aspects of the discs were exposed by the incision of the articular eminence. Group
2. Fifteen TMJs in which the discs were perforated.
Group 3. Twenty-one TMJs in which the dermal grafts were sutured on the disc perforations.
The results obtained were as follows: In group 2, all perforations were not repaired, except in one case. In group 3, 14/19 grafted disc perforations were repaired. One week after surgery, young, loose, collagenous tissue from the synovial membrane lined the margins of the perforations. Two weeks after surgery, vascularity from the synovial membrane and young collagen fibers were seen in the area of the repaired perforations. Four weeks after surgery, long and thick collagen fibers bridged the perforations.View full abstractDownload PDF (31231K) -
Shigeyuki Matsumoto1991 Volume 58 Issue 2 Pages 403-446
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSThe purpose of this study is to discuss the stuctural changes of the surrounding tissue around the implant cavity when the influence of tooth extraction is still remaining. At 3 months after the extraction of the dog lower teeth, implant cavities were prepared. Histological examinations were performed on the specimens at 30 minutes, 2 days, 5 days and 10 days.
Results : 1) At 3 months after the tooth extraction, enhanced bone remodeling looks like a typical one in the compact bone area.
2) The bones formed after the extraction, by alternate resorption and formation with time, were replaced by higher differentiated ones.
3) At 5 days, by the implant cavity formation, bone addition is seen on the inner and outer surfaces of the compact bone.
4) Inside the extraction socket, the changes in the shape and structure of the trabeculae, which are influenced by the implant cavity preparation, are seen near the deep zone of the implant cavity and gradually with time they could be seen in the shallow zone and away from the implant cavity.
5) The newly formed trabeculae inside the implant cavity are mainly type I and on a part of the suface there is the addition of type II.View full abstractDownload PDF (33198K) -
Atsuhiro Kinoshita1991 Volume 58 Issue 2 Pages 447-474
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSThe purpose of this study was to investigate the structure of the matrix in regenerated cementum on surgically denuded root dentin and on acid-demineralized root dentin in dogs. Nondecalcified specimens were examined two to 16 weeks after surgery. The arrangement of the matrix fiber, the fiber component and the crystal deposition of the cementum were studied by light microscopy and electron microscopy.
The results were as follows:
1. There were many differences in the structures of regenerated cementum. The differences were dependent on the presence of resorption of the root dentin, existence of lamellar structure, and density of Sharpey's fibers.
2. Regions without surface resorption of dentin exhibited a dense deposition of crystallites and a rare arrangement of collagen fibrils at the cementodentinal junction.
3. Regions of surface resorption of dentin exhibited a layer where dentinal and cemental crystallites were amalgamated, and/or dentinal and cemental matrix fibers were interdigitated at the cementodentinal junction.
4. Regions subjected to artificial demineralization by citric acid exhibited similar structure to that where surface resorption of dentin was observed.
5. It is suggested that the resorption of dentinal surface during the healing process of a surgically created wound in periodontal tissue occurred as an intermediate stage followed by the establishment of a stronger bind by the increase of superficial contact area at the cementodentinal junction.View full abstractDownload PDF (22283K) -
Effects of Glass-Ceramics on Growth and Differenti. a¥tion of Human Periodontal Ligament-derived CellsHitoshi Mukohyama1991 Volume 58 Issue 2 Pages 475-489
Published: 1991
Released on J-STAGE: November 29, 2010
JOURNAL FREE ACCESSThe hybrid-type dental implants which are composed of substrates and periodontal ligamentderived cells are expected to form the periodontal ligament-like tissue around the dental implant. The purpose of this study was to investigate the possibility of the application of glass-ceramics GC) as the substrate using the human periodontal ligament-derived cells (PL cells) . (The growth and differentiation of the PL cells on the GC were investigated, as compared to the hydroxyapatite plates and the conventional plastic dishes. The Ca concentration of the media was also measured. The results were as follows:
1) The PL cells were fibroblastic of spindle shape. The population doubling time was approximately 26 hours.
2) The PL cells exhibited an alkaline phosphatase (ALPase) activity, collagen productivity and responsiveness to 1α, 25-dihydroxyvitamin D3.
3) The PL cells proliferated favorably both on the mirror-polished and 2000-polished GC plates as well as on the hydroxyapatite plates.
4) The ALPase activity of the PL cells on the GC increased in a time-dependent manner.
5) The GC released Ca into the media.
The PL cells possessed some characteristics of periodontal ligaments, and the growth and differentiation of the PL cells were not impaired significantly on the GC. The GC also provided the dental implant with enough biocompatibility and strength. These results promised the usefulness of the GC as the possible substrate for the hybrid-type dental implants.View full abstractDownload PDF (6442K) -
Histological Observation on Implant and Im. p¥lant Covered with Autogenous Iliac Bone. ¥Shuichiro Ishihara1991 Volume 58 Issue 2 Pages 490-528
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSThe purpose of this study was to investigate the possibility of applying the hydroxyapatite implant and the hydroxyapatite implant covered with autogenous iliac bone to the augmented mandible. Three months after the extractions of the lower P3, P4, and M1 of mongrel dogs, alveolar ridge augmentations were performed widely with porous hydroxyapatite granules. After one month, the hydroxyapatite implants were inserted in the iliac bone of the same dog. Four months after the augmentation, the hydroxyapatite implant and the hydroxyapatite implant covered with autogenous iliac bone were implanted only in the augmented area with the granules of the mandible. Two months later, specimens were taken out and fixed by 10% formalin alcohol. They were embedded in polyester resin and undecalcified sections were prepared. The sections were stained with toluidine blue and observed under light microscope.
Results:
1) Bone ingrowth was seen in most parts of the intergranular spaces and in some spaces fibrous connective tissues were observed.
2) The hydroxyapatite implant was partly attached to the bone. But a large surface of the implant was connected to the fibrous tissues among the granules.
3) The hydroxyapatite implant covered with the iliac bone was combined with the bone of the intergranular spaces.View full abstractDownload PDF (25652K) -
Tohru Nakajima1991 Volume 58 Issue 2 Pages 529-544
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSThe purpose of this study was to investigate the hypergravity-induced responses and their mediators of osteoblastic cell line, MC3T3-E1. The synchronized G1 or the S Phase cells were exposed to 5 and 18×g hypergravity at 37°C. The migration velocity was measured and the morphology was observed. MC3T3-E1 cells were cultured for 1, 2 or 3 days at 37°C, exposing to 5, 10, 20 and 40×g hypergravity. The proliferation, prostaglandin E2 (PGE2) production rate and alkaline phosphatase (ALPase) activity were measured. The results were as follows:
1) In the G1 phase of the cell cycle, the migration of MC3T3-E1 cells was increased by 18×g. In the S phase, the morphology altered depending on the g-stress.
2) The proliferation of MC3T3-E1 cells was enhanced at 20 and 40×g but reduced at 10×g. The proliferation of HeLa cells and JTC-12 cells was also enhanced at 40×g.
3) Indomethacin (10-5M) reduced the proliferation of MC3T3-E1 cells induced by 40×g. But indomethacin (10-5M) did not reduce the proliferation of HeLa cells.
4) The increase of the released PGE2 from the cells depended on the time (1-8h) and the gravity (1-40×g) .
5) The increase of the ALPase activiy of MC3T3-E1 cells also depended on the gravity.
These results suggest that the hypergravity enhanced the proliferation of MC3T3-E1 cells via PGE2-mediated mechanism.View full abstractDownload PDF (8964K) -
Kouji Araki, Atsushi Takeda, Arata Ebihara, Hiroyuki Matsumoto, Hideak ...1991 Volume 58 Issue 2 Pages 545-554
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSIn clinical education in dentistry, it is very important and significant that the undergraduate students themselves treat the patients. According to the rapid progress of dental science, the complexity and the highdegree of the quality of education increase more and more, so that it is a requisite to make our efforts to enrich the quality of the practice at all times.
In this paper, we investigated and statistically analyzed the result of 3, 359 cases (test cases: 304, general cases: 3, 055) which were treated endodontically by the undergraduate students of Tokyo Medical and Dental University in the four classes of 1979, 1982, 1986 and 1989.
Both the number of the treated cases and the patients decreased year by year. Only the patients above sixty years old showed a tendency to increase in number. The result of the test cases was not always representative of the result of the general cases.
If the clinical instructors for the undergraduate students grasp the detailed results of this study, we can expect that they can guide and train the undergraduate students more effectively.View full abstractDownload PDF (1850K) -
[in Japanese], [in Japanese], [in Japanese], [in Japanese]1991 Volume 58 Issue 2 Pages 555-565
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSTapering and branching of the nerve fibers cause the conduction velocity (CV) along the axon to be unequal. The purpose of this study was to investigate the response properties of the myelinated and unmyelinated nerve fibers in the cat tooth pulp. Electrophysiological recordings were made from the functional single fibers innervating the lower canine tooth pulp in 25 adult cats anesthetized with pentobarbital sodium after the application of four types of stimuli to the canine tooth. A total of 272 single pulpal nerve fibers was identified. A-fibers (n=215) were divided into two groups: One (Ac, n=55) consisting of the fibers whose intrapulpal CVs were less than 2m/s and the extrapulpal CVs of more than 2m/s, and the other (At, n=160) consisting of the fibers whose CVs were more than 2m/s both inside and outside the tooth pulp. Fiftyseven C-fibers (C) were also found. None of C, 47% of At and 46% ofAc responded to the rapid elevation of the temperature. None of At, 38, % of Ac and 53% of C responded to the continuous heat. None of C, 20% of At and 20% of Ac responded to the hydrostatic pressure. None of At, 86% of Ac and all of C responded to bradykinin. These results suggest that the functional difference between the pulpal A-and C-fibers is not clear and that the Ac-fibers may complicate the dental and pulpal pain.View full abstractDownload PDF (1901K) -
Fujio Miura, Kunimichi Soma, Takehiro Kuroki, Toshihiko Fukawa, Tetsuy ...1991 Volume 58 Issue 2 Pages 566-579
Published: 1991
Released on J-STAGE: October 27, 2010
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[in Japanese]1991 Volume 58 Issue 2 Pages 580
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSDownload PDF (225K) -
[in Japanese], [in Japanese]1991 Volume 58 Issue 2 Pages 581
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSDownload PDF (2206K) -
[in Japanese], [in Japanese]1991 Volume 58 Issue 2 Pages 582
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSDownload PDF (181K) -
[in Japanese]1991 Volume 58 Issue 2 Pages 583
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSDownload PDF (228K) -
[in Japanese]1991 Volume 58 Issue 2 Pages 584
Published: 1991
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSDownload PDF (1657K)
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