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高分子電解質錯体と骨芽細胞との相互作用
若林 克敏
1996 年 40 巻 5 号 p.
831-842
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to assess whether polyelectrolyte complexes (PECs) produced by the combination of oppositely charged polyelectrolyte aqueous polycations and polyanions were suitable as new biomaterials for the reconstruction of osseous tissue (carrier of BMP).
The 90 types of PEC, produced by combining 6 types of polycations with 15 types of polyanions, were coated on cell culture dishes to investigate the interactions between various types of PEC and osteogenic cell line MC 3 T 3-E 1 cells at the cellular level, and emphasis was placed on cell adhesion, proliferation, and differentiation. Among the 90 types of PEC studied, 18 were equal to or nearly equal to those on non-PECcoated control dishes with respect to cell adhesion, proliferation, and ALP activity. Properties and surface charge associated with differences in the functional groups of the polymers appeared to be important factors in cell adhesion, proliferation, and differentiation.
These results suggested that the 18 types of PEC that showed good cell adhesion, proliferation, and differentiation are carriers that have no negative effect on the physiological functions of cells; these PECs are promising as biomaterials for the reconstruction of osseous tissue (carrier of BMP).
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各種ラミネートベニア材料の光透過性について
島田 和基, 河原 一茂, 宮島 和臣, 小見山 信, 中本 宏, 杉澤 肇, 今 悟, 朝比奈 利早子, 桟 淑行, 五十嵐 孝義
1996 年 40 巻 5 号 p.
843-852
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
To evaluate light transmission of various laminate veneer materials, spectral transmittance, and the value of L*a*b* using transmitted light and luminous transmittance were determined. The results were as follows:
1. Porcelain
In short wavelength light, i.e., violet to blue light, transmittance decreased conspicuously. Spectral and luminous transmittance decreased as thickness of masking dentin increased.
2. Dicor
The difference between spectral and luminous transmittance due to presence or absence of white layer was slight, and the decrease of transmittance in short wavelength light was little. By applying shading porcelain, transmittance decreased.
3. IPS Empress
In luminous transmittance, light was transmitted more in the order of Ti, T2, O1, and O2. After staining, decrease of transmittance in short wavelength light was greater than that before staining.
4. Comparison between different types of materials
In all of the three types of materials, transmittance decreased in short wavelength light, and the difference of transmittance was noted at this site. In luminous transmittance, light was transmitted more in the order of Dicor, Porcelain, and IPS Empress.
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第2報金属組織学的検討
鬼塚 雅, 中島 厚生, 松下 容子, 門川 明彦, 末永 健市, 自見 忠
1996 年 40 巻 5 号 p.
853-860
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
Though cast restoration is the major skill to make prosthesis today, sintered metal restoration by brush application is being investigated and has wide possibilities. As metallographic examination, sintered specimens (S) and conventional cast specimens (C) were compared by SEM observation, X-ray mappings and volume of surface roughness. The results were as follows:
1. In comparison of surface roughness of polished cutting surfaces after casting, surface roughness C was smaller than S. SEM observation showed few micro pits on the S surface, and there were some spaces which were supposed to be gas holes. While the cutting surface of C was generally rough, the S surface showed brush streaks and indentations which averaged 3μm in depth, in the intergranular area.
2. After the corrosion test in aqua regia, both C and S showed corrosion on the polished surface. The intergranular area was corroded on the C surface and showed tortoise-shell pattern, and selective corrosion was observed inside the crystal grain. There were fusions and spaces between alloy grains of S, and the width of the space was smaller than that of C. No element was found in this space by elementary analysis, hence these spaces were empty. As for the results of surface roughness, S was smaller than C.
Based on these results, it is suggested that the corrosion resistance of S is superior to that of C from the metallographical point of view.
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三次元光弾性実験による応力解析
南 弘之, 鬼塚 雅, 中島 厚生, 山邉 成志, 中島 由佳, 野村 賢介, 嶺崎 良人, 自見 忠
1996 年 40 巻 5 号 p.
861-871
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to investigate the stress distribution of all-ceramic crowns made of castable glass ceramics coping with and completely veneered by dental porcelain, using three-dimensional photoelastic stress analysis technique under a static load. Two-layered photoelastic models were made of epoxy resin. Four different loading sites were chosen, and stress was frozen.
The results obtained in each model were as follows:
1. Severe stress was observed in the vicinity of loading sites, and there was a strong possibility of fracture.
2. Relatively low tensile stress was observed at the incisal half of the labial surface and around the cingulum of the lingual surface.
3. Relatively high compressive stress was observed around the labial and lingual cervixes. This is considered to be mesiodistal tensile stress, and may be related to cervical semicircular fracture, with tensile stress around the cingulum.
4. Danger of fracture from the internal surface was suggested.
5. Compressive and tensile stresses tended to decrease in areas away from loading sites, compared to the partially veneered type, and superiority of complete veneered type was indicated.
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セラミック研磨材の材質と粒径が表面性状に及ぼす影響
谷 信幸, 山森 徹雄, 阿久津 三幸, 植原 典子, 島崎 政人, 高橋 秀美, 清野 和夫, 長山 克也
1996 年 40 巻 5 号 p.
872-877
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to investigate the surface texture and the cutting depth of denture base resin after barrel finishing, in association with the component and the particle size of the ceramic polishing materials. Board-shaped specimens were provided to examine the surface texture, and cylindrical specimens were provided to measure the cutting depth. The test surface of the board-shaped specimens were polished with a rag wheel and polishing material (0.05 pm aluminium oxide powder) before barrel finishing. The test surface of the cylindrical specimens were polished in the same manner, and then the polished surface was masked with adhesive tape except for a circular hole which was five millimeters in diameter. The barrel finishing was performed for twenty minutes with six kinds of ceramic polishing materials respectively. After barrel finishing, the surface texture and the cutting depth were measured with a surface texture measuring apparatus. Then the specimens were observed under a scanning electron microscope. The results were as follows:
1. As the diameter of ceramic polishing materials increased, the value of the surface roughness and the cutting depth increased.
2. The surface texture of denture base resin was influenced by components of polishing materials when the diameter of the ceramic polishing material was 2 or 4 mm.
3. The cutting depth of the denture base resin was not influenced by components of polishing materials.
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第2報マスキングポーセレンの着色成分にデンティンを用いた場合の色調構築精度
多田 建造, 永井 成美, 辰巳 浩輝, 沢藤 太, 遠藤 忠治, 石橋 寛二, 村田 幸男
1996 年 40 巻 5 号 p.
878-883
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
Porcelain laminate veneer crown is an excellent system to improve the color of a discolored tooth in the anterior region having occlusal contact. Since masking porcelain of porcelain laminate veneer crown has opacity for hiding the discolored tooth, it was difficult to give a high translucency to the laminate crowns by conventional methods.
The purpose of this study was to produce the natural color and excellent appearance of laminate crowns with adequate translucency using the Computer Color Matching (CCM) System to compensate opacity of masking porcelain.
Construction of CCM sample, discolored layer, and procedure of CCM formulation are the same as part 1.In this study, 1 kind of opaque porcelain was used as the hiding element, and 3 kinds of dentin were used as the coloring element. According to the CCM formulation, masking porcelain was baked and the CCM samples were made.
In comparison of the target color and CCM sample, both reflectance curves were very similar and color difference dE was under 3.0. Furtheremore, CCM samples showed the color to be indistinguishable from the target color by the naked eye.
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実験条件について
小林 國彦
1996 年 40 巻 5 号 p.
884-894
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to investigate the experimental conditions of in vitro attrition testing that can predict clinical performance of restorative materials in the occlusal contact area.
The experiments were performed using the sliding abrasion testing machine developed in our department. The upper specimens, made of extracted sound human premolar teeth and a commercial posterior composite resin (Clearfil Photo-Posterior, Kuraray), were made into hemispherical shapes (five each). The lower specimens, made of extracted sound human maxillary anterior teeth, were flattened smooth with emery papers. A load was applied between the upper and lower specimens which were slid in solution under various different conditions. After the specimens were slid a certain number of times under load, wear was evaluated by measuring the width and depth of the lower specimens.
The results showed that there was a considerable difference in the wear of tooth enamel between composite resin to enamel and enamel to enamel in every condition, and that the weight of load, kind of solution, and sliding speed all had an effect on the wear. The cause of this difference remains to be explored. A definite conclusion cannot be drawn due to the insufficient number of experiments, but experimental conditions that were similar to the actual condition in the oral cavity were obtained.
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第1報タンニン・フッ化物合剤による齲蝕予防
山賀 保, 辰巳 滋也, 曽我 幸史, 小野 雅則, 糸坂 直志, 野首 孝祠
1996 年 40 巻 5 号 p.
895-900
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
Non-coping method for overdenture abutment teeth has several advantages such as avoiding mechanical irritation to the marginal gingiva, allowing patients to make a smooth transition to the overdenture, and facilitating the detection of caries of abutment teeth in their early stage. Tannin-fluoride (HY) preparation strengthens both the inorganic and organic components of teeth. In this study, the preparation was used for caries prevention of the non-coping abutment teeth for periods varying from one to twelve years.
Seventy (76.9%) of 91 observation teeth were still non-coping abutment teeth, 14 teeth (15.4%) needed coping restoration, and 7 teeth (7.7%) were extracted due to caries (2 teeth) or periodontal disease (5 teeth).
The percentages of coping restoration and extraction due to caries in the HY treatment group showed a tendency to be lower than those in the non-treatment group, especially in periods of five to eight years (p>0.05).
It became clear that the non-coping method could be useful for overdenture abutment in caries prevention such as the tannin-fluoride preparation.
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その1. ピシホール形成器, ピンホールの精度ならびに部位の設定
山下 敦, 白井 知恵子, 今井 誠, 岡本 壮一郎
1996 年 40 巻 5 号 p.
901-908
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
To diminish the amount of irreversible tooth reduction during preparation for a fixed restoration of missing teeth, supplementary preparation of small pins in addition to conventional tooth reduction techniques has been advocated. Among them, the most epoch-making one might be UDA system reported by S. Sandhaus in 1985, making it possible to support the conventional pontic structure with minimal tooth reduction (pin holes) prepared on the proximal tooth surfaces of the abutment teeth. However, the diameter and length of the pins and the head size of the preparation instrument was eventually too big for Japanese adults who have less thick teeth. On the basis of the concept, we redesigned the whole system (pin size, preparation instrument head) for Japanese adults. Furthermore, to reinforce the reduced mechanical retention ascribed to the reduced adherent area of the newly-designed smaller pin to the smaller pin hole, titanium-nickel shape memory alloy was utilized. In this paper, the detail of the pinhole preparation instrument was described and its redone precision of the holes prepared by the instrument was assessed. The standard deviation range of the diameter of the prepared pin-holes was from 1/100 to 5/100 mm. Based on the X-ray estimation of the enamel and dentin thickness in the proximal tooth surface of an extracted tooth sample, the most suitable pin hole position for each tooth was advocated.
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内野 高明
1996 年 40 巻 5 号 p.
909-916
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to investigate the kinesiological regulation of mandibular motor system.
Nine healthy participants were instructed to do rhythmical jaw tapping movement at the opening distance of 1-2, 5, 10, 15, 20, 30 mm, Maximun, and ad
lib.
The results were as follows:
1. Visual feed-back caused the regulation of the opening distances. The effect persisted more than 30 sec after the feed-back training.
2. Mean closing velocity was most significantly varied with various opening distances. Mean opening velocity, cycle time, and appearance rate of plateau phase were also significantly influenced by them.
3. Cycle time was constant within the ranges of opening distances of 1-2 mm to 5 mm and of 10 mm to 20 mm.
4. As the opening distance increased, mean closing velocity and opening velocity significantly became faster, and the adjustable range of the former was wider than the latter.
5. The appearance rates of the plateau phase at 30 mm- and maximum-opening tappings were higher than those at 1-2 mm-and ad
lib-tappings.
6. The above results suggested that the regulating mechanism of jaw tappings with constant opening distance would consist of the layered regulation system, which would make the duration of tooth contact phase fixed and cycle time constant.
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咬合挙上が舌形状に及ぼす影響について
市川 哲雄, 森川 葉子, 堀内 政信, 松本 直之
1996 年 40 巻 5 号 p.
917-921
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The tongue is a principal organ of the masticatory system that helps to prepare the food bolus with coordination of the teeth and mandible. Dynamic measurement method of the tongue shape was developed using an ultrasonic and CCD camera systems. The ultrasonic system consisted of a 3.5 MHz transducer whose beam scans the sector area of 90 degrees angle along the dorsum and the detector. To know the relative position of the probe to the head, markers attached to the probe and glasses detected using a CCD camera simultaneously during the ultrasonic measurement. Both signals of the ultrasonic and CCD camera were superimposed in an image signal using an audio-visual mixer and then the signal was digitized by a computer. The tongue and palatal shapes at a desired time were measured with image processing software after adjusting the movements of the head and probe.
The tongue shape to the palate was measured at the rest position of occlusion and at the time of increase of vertical dimension. The anterior portion of the tongue was coherent to the anterior palatal contour at the rest position. The tongue was often positioned to rear-downward at the time of increase of vertical dimension with the decrease of curvature of tongue.
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北山 展弘, 戸田 伊紀, 河村 達也, 権田 悦通
1996 年 40 巻 5 号 p.
922-926
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
Recently, more concern has been directed to pen-abutment tissues as they relate to the marginal design of the superstructure, hygiene management, and sequelae of peri-implantitis. Especially, since penabutment tissues lack periodontium, whether or not they play a role as a biological defense mechanism against various external stimuli has been in question. In this study, the microvasculature around implant was investigated.
Titanium screw-type implants were used in this study. Three adult Japanese monkeys were used. At weeks 2, 4, and 8 after the abutment connection, the animals were sacrificed, and microvascular casts were prepared for examination by scanning electron microscopy.
At week 8, as was observed at weeks 2 and 4, the capillary network surrounding the abutment had developed a running horizontal structure and was well defined. At the superior margin of the alveolar bone, the pen-abutment capillary network was anastomosed to the periosteum capillary network. Extension of the pen-abutment capillary network into the alveolar bone surface corresponding to the fixture flange was not observed.
If peri-implantitis exacerbates, or lasts long, due to poor microvascularization lacking periodontal ligament in this region, it is easy for external stimuli to cause damage the alveolar bone. Hygiene control around the implant is more important than around natural teeth.
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第1報イオンピュアTMの各種毒性試験
水川 一廣, 田中 孝明, 妻鹿 純一, 小林 平, 渡辺 官
1996 年 40 巻 5 号 p.
927-932
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
Hitherto, many kinds of anti-bacterial reagents have been developed. Those anti-bacterial reagents could be divided into two groups such as organic and inorganic reagents. The silver-inorganic reagents have been interesting as a substitute for the organic reagent, since those inorganic reagents might resolve the problems of organic reagents such as the short-term durability of anti-bacterial effect, degeneration by proceeding or heating operation, and physical irritation. The purpose of this study was to investigate whether or not the silver-inorganic reagents could be applied biologically to dental materials. Ionpure
TMwas used as the silver-inorganic anti-bacterial reagent. Biological reactions of Ionpure were measured by the standard biological tests such as the toxic tests proposed by OECD and patch test by Kawai's method.
The results were as follows
1. In acute toxicity testing by oral ingestion of Ionpure, no mortality of mice was observed by the single dose of 5, 000 mg/kg. Lethal dose by oral ingestion of Ionpure was estimated to be more than 5, 000 mg/kg. The general condition, including the average weight, did not indicate abnormal signs during the experimental period. Furthermore, no pathological finding was observed in the internal organs by dissection after testing.
2. In the dermal sensitization by modified Draize test, the eye irritation test, and the mutagenesis test, Ionpure was evaluated to be negative, whereas the evaluation of the patch test by Kawai's method was semi-negative.
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第1報試作双極針電極と刺入方向指示装置
岡部 良博, 榎澤 宗司, 藍 稔, 屋嘉 智彦, 佐藤 雅之, 西山 暁
1996 年 40 巻 5 号 p.
933-939
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
In order to conduct the EMG activity of the human medial pterygoid muscle, a bipolar needle electrode (Thumbtack type) was newly devised and an aid (Needle indicator) to insertion of the electrode into the muscle was made.
Then the activity of the medial pterygoid muscle during clenching was recorded by using them and investigated.
The results were as follows:
1. The bipolar needle electrode formed as a thumbtack was easy to handle and to insert into the medial pterygoid muscle.
2. The apparatus, which could indicate the orientation of the medial pterygoid muscle on the mandibular angle, was very useful when inserting the electrode into the muscle.
3. The original waves of EMG during tasks were clear and did not hinder the quantification of EMG.
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第4報スレッドピッチが周囲骨内応力に及ぼす影響
松下 恭之, 古谷野 潔, 鳥谷 浩平, 伊山 規矩子, 平井 友成, 末次 恒夫
1996 年 40 巻 5 号 p.
940-945
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to investigate the effect of various thread pitches on stress distribution in bone around a dental implant. Both bone-bonded and bone-adapted titanium cylindrical implants were studied by finite element analysis. In the bone-adapted model, the slip element was used at the interface between the bone and implant. The results were as follows:
1. In bone-bonded titanium implants, stress concentration was observed at the cortical bone around the neck of the implant. Various thread pitches scarcely affected stress distribution and stress value in bone around the implant.
2. In bone-adapted titanium implants, stress concentration was observed widely at the cancellous bone around thread ridges and bottom of the implant as well as at the cortical bone around neck of the implant. Stress value in bone reduced as the thread pitch became small. These results suggested that smaller thread pitch was better from the biomechanical point of view.
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梶村 幸市, 塩山 司山, 山森 徹雄, 伊藤 創造, 細川 貢, 島崎 伸子, 有住 達也, 石橋 寛二, 石沢 均
1996 年 40 巻 5 号 p.
946-951
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The surface characteristic of titanium was improve by developing a hydroxyapatite film on top of an anodic titanium oxide film containing Ca and P via hydrothermal treatment (SA treatment). This study was conducted to investigate how SA treated implants affect the surrounding bone tissue based on early stage histological observations after insertion.
Cylindrical plasma sprayed pure titanium implants and SA treated plasma sprayed pure titanium implants were inserted into the mandible of beagles. Four weeks after insertion, undercalcified samples were observed by light microscopy.
The results suggested that SA treated implants have more contact directly with surrounding bone tissue than titanium implants, leading to the conclusion that SA treatment increased the compatibility of the titanium surface, and was found to be a useful method for inducing early bone formation around implant.
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山下 潤朗
1996 年 40 巻 5 号 p.
952-963
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
Surface strain of crowns and bridges were measured by the strain gauge method. A static load was applied with occlusal force in vivo and with a universal testing machine
in vitro.
The conclusions were as follows:
1. The marginal portion under the cusp loaded in function was strained largely in the crowns both
in vivoand in vitro. The strain tended to be localized.
2. In the bridges, the marginal portion under the cusp loaded in function was strained largely
in vitro.However, the whole portion of the bridges was strained in vivo.
3. The bridge's strain value was large on the buccal and the lingual marginal portions of the distal retainer and on the distal connector
in vivo. The magnitude ranged between 700 and 1, 000 με under the occlusal force of 200 N.
4. The strain distribution of the bridges which differ from those of the crowns is complex and is affected by many factors such as abutment tooth mobility and jaw deformation, in addition to span length, marginal shapes, and metal thickness.
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池田 圭介, 河野 正司, 土田 幸弘, 松山 圃士, 大竹 博之
1996 年 40 巻 5 号 p.
964-971
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to investigate an optimum condition for tapping movements for bite registration. The closing path of inicisal and condylar tracking points were measured with a system for recording jaw movements in 6 degrees of freedom during tapping mevements in five normal subjects under various conditions such as different head positions (Camper plane, Frankfort plane; parallel to the floor), tapping frequency (2 Hz, 3 Hz), and interincisal distance (20 mm, 30 mm).
The most stable position of the condyle was found by plotting both tracking points, on which almost pure mandibular rotation was observed. Each tapping condition was evaluated by comparing the incisal path's range of rotation of the vertical component, which was termed the rotation value of the mandible.
Results: When the head was positioned on the Camper plane, with a 3 Hz tapping frequency at a interincisal distance of 30 mm, the highest rotation value was found ; the most posterior closing path of the mandible recorded at the most condylar stable position did not cause posterior displacement of the condyle.
It is concluded that a reliable bite registration can be obtained by using the most posterior closing path of the mandible as reference when the above mentioned tapping conditions are met.
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第1報3次元有限要素解析の導入
篠原 直幸, 石田 修, 門川 明彦, 中原 淳, 松下 容子, 奥家 信宏, 梶原 浩忠, 嶺崎 良人
1996 年 40 巻 5 号 p.
972-979
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
Direct retainer's arm is placed on an abutment tooth when an edentulous space is restored by prosthetic treatment with a removable partial denture. Various attempts have been made to investigate the effects of the retainer of a partial denture on an abutment tooth during functional loading. However, no analysis seems to have been reported about the effects of retainers on the abutment teeth when the denture base rotates toward and away from an edentulous ridge. Attention was paid to the lower second premolar tooth, and the three-dimensional finite element method was used.
The results were as follows:
1. When only a retentive force was applied, the von Mises stress in the periodontal ligement increased.
2. When both retentive and reciprocal forces were properly applied, the von Mises stress in the periodontal ligament was less than that with the retentive force only.
3. When both retentive and reciprocal forces were properly set, and a reciprocal force was one-third of a retentive one, the value of the von Mises stress was within 2.4 MPa. Thus, it was suggested that the reciprocation effectively released the stress in the periodontal ligament of an abutment tooth.
4. Effective factors for stress relaxation of the periodontal ligament were suggested to exist in the design of a retainer's arm.
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服部 孝治, 畑 好昭, 後藤 真一
1996 年 40 巻 5 号 p.
980-992
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
Tension, strength, and tarnish test pieces and die model for deformation measurements were prepared by using 12% Au-Pd-Ag alloys containing 20% Cu (GC Castwell MC 12, GCW) and 10% Cu (Tokuriki, New Paragold, TKG). The test pieces were heated at 700, 750, 800, 850, and 900°C for 10 min, and after solution heat treatment (solHt), softening heat treatment (SHt) was performed by quenching them. Then half of them were furnace-cooled from 450°C to 250°C over a 30 min period and subjected to hardening heat treatment (HHt). Then the measured values were analyzed in relation to the temperature of solHt, and the results were as follows.
1. Vickers hardness (Hv) increased almost linearly at solHt of 750°C and above when SHt was performed with GCW, whereas with TKG, there was no change in Hv from 700 to 850°C.
2. When subjected to HHt by identical furnace cooling, the hardness of GCW increased as the temperature of solHt rose, whereas with TGK it was increased by solHt at 750°C and above.
3. When GCW was solution heat-treated at 850°C and hardening heat-treated, tensile strength reached at least 1, 000 MPa, but when heat-treated at 900°C, SHt and HHt strength diminished considerably.
4. Elongation of GCW after SHt was 20% when solHt at 750°C, and decreased linearly as the temperature rose. The treatment temperature did not have much effect on TKG.
5. HHt elongation decreased in inverse proportion to the temperature of solHt.
6. Deformation of most of the models occurred during quenching.
7. Lightness after the tarnish test, L*, was not greatly affected by the temperature of SHt.
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上田 康夫
1996 年 40 巻 5 号 p.
993-1003
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The introduction of CAD/CAM technology was tried for the improvement of the quality of prosthetic restoration and of efficiency of the dental technician's work.
In this study, CAD was examined as a method for prosthetic restoration, and as a result, the conclusions were as follows:
1. In order to design a tooth crown form by computer, it was necessary to freely treat a tooth crown form that has a complex three-dimensional freedom curved surface.
2. For this purpose, voxel model, spline model, and rational bezier model were examined. The data of the voxel model was easy to treat but difficult to transform effectively, and the problem there of was the quantity of data increased when the surface was smoother. In case of the rational bezier model, it was possible to transform the model according to expectation.
3. As one method of transformation of the tooth crown form using rational bezier surface, it was advantageous to transform without changing the control points by changing the weight-parameters.
4. The CAD system for prosthetic restoration was based on MCCM-solid-model using rational bezier surface, and it was found to be possible to make the prosthetic restoration in this CAD system like those made in dental technical work.
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松本 真二, 更谷 啓治
1996 年 40 巻 5 号 p.
1004-1014
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to investigate daily variation of horizontal (labio-lingual) tooth mobility by measuring viscoelastic properties of periodontium. Horizontal tooth mobility of maxillary central incisors was measured by an automatic diagnostic system for tooth mobility.
Three males and five females participated in this study. Their periodontal conditions were clinically normal. Horizontal tooth mobility was measured once a day between 11: 30 a.m. and 12:30 p.m. before lunch. Basal body temperature was also recorded for the females. Measurements were repeated daily except for holidays, for about 30 days in the males and about 50 days in the females. Horizontal tooth mobility was determined for three viscoelastic parameters (C
1, C
2, and k).
Daily variations were in each of the parameters in the males and females. Two parameters (C
1, C
2) were smaller during the high temperature period of the menstrual cycle (luteum phase) than during the low period (follicular phase). It was concluded that daily variations exist in horizontal tooth mobility in both sexes, and horizontal tooth mobility is greater during the luteum phase than during the follicular phase.
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西田 美香, 古谷野 潔, 小川 隆広, 末次 恒夫
1996 年 40 巻 5 号 p.
1015-1020
発行日: 1996/10/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to investigate the characteristics of masticatory movement in different chewing regions. Eleven normal subjects were instructed to perform the masticatory movement in two different regions, canine/premolar region and molar region. The masticatory movement was measured by 3-D Mandibular Movement Analyzing System. The results were as follows:
1. A significant difference was found in the opening distance between canine/premolar chewing and molar chewing.
2. A significant difference was found in the lateral displacement of the lowest point of chewing between canine/premolar chewing and molar chewing.
3. A significant difference was found in the frontal angle of chewing between canine/premolar chewing and molar chewing.
4. A significant difference was not found in the chewing cycle between canine/premolar chewing and molar chewing.
5. A significant difference was found in the displacement of kinematic axis between canine/premolar chewig and molar chewing.
It was suggested that there was great difference between canine/premolar chewing and molar chewing.
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1996 年 40 巻 5 号 p.
1023
発行日: 1996年
公開日: 2010/08/10
ジャーナル
フリー
