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ピンブリッジ法
山下 敦, 今井 誠, 白井 知恵子
1996 年 40 巻 3 号 p.
419-425
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Several less-invasive intervention techniques for single or several missing teeth, e.g., a fixed partial denture supported by resin-bonded cast retainers, single-standing bone-anchored prosthesis, have been advocated to recover its functionality. However, the non-invasiveness of the techniques could never be estimated sufficient in consideration of risk-benefit. Recently, we developed a fixed partial denture supported by tiny shape memory alloy (Ti-Ni alloy) pins attached to proximal surfaces of abutment teeth by an adhesive composite resin cement. Strong retention of the tiny proximal pins could be accomplished by the morphological recovery within the Titanium-nickel shape memory alloy end and excellent adhesivity of the adhesive resin, tooth surfaces, and Ti-Ni alloy. A pontic for the prosthesis was permanently fixed with an adhesive composite resin cement and estimated functional recovery were excellent under a small amount of tooth reduction. The special advantages of this method were the excellent less-invasiveness of the total procedure and the promised long-term durability.
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森戸 光彦, 細井 紀雄
1996 年 40 巻 3 号 p.
426-432
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
The dental magnetic attachment exerts less force laterally on an abutment tooth than conventional dental attachments, so it has wide application to various prosthesis. However, some defects of MRI are produced due to the magnetism of the keeper. Therefore, three kinds of stainless steel used as dental magnetic keeper and a composite resin fabricated with stainless steel powder as filler were examined to investigate the extent of the distortion of MRI. Factors for examination were differences and size of keepers. The purpose of this study was to explore the possibility of expanding the range of diagnosis with MRI, in relation to improvement of the keeper. The results were as follows:
1. The SUS 430 stainless steel, as a material for the dental magnetic keeper, had the least distortion of MRI, and the distortion increased in the order of composite resin, SUS 447 J 1 and AUM 20.
2. Keepers that were cut on both sides in parallel, had smaller diameters, or were thinner had less influence.
3. In order to minimize the effect on MRI, it was suggested that it may be necessity to investigate materials and miniature the dental magnetic keeper.
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実験的咬合干渉が自律神経機能に及ぼす影響
豊田 將盟
1996 年 40 巻 3 号 p.
433-441
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
As part of a study to clarify the effects of changes in the stomatognathic system on autonomic functions, experimental occlusal interference was applied to the mandibular molar on the primary mastication side in 10 healthy subjects with natural teeth. Then examination was carried out on daily changes in the heights of digital plethysmograms and the R-R intervals on the electrocardiogram as well as their coefficients of variation. The results were as follows:
1. The heights of digital plethysmograms had decreased 24 hours after the interference was applied but increased daily after its removal, returning nearly to the pre-interference value after another 48 hours. The coefficient of variation had increased 24 hours after the interference was applied but decreased daily after its removal, nearly recovering the pre-interference value after 48 hours.
2. The R-R interval on the electrocardiogram had decreased 24 hours after the interference was applied but had nearly recovered its pre-interference value 24 hours after the interference was removed. The coefficient of variation had decreased 24 hours after the interference was applied but recovered daily after its removal, nearly recovering the pre-interference value after 48 hours.
3. These results suggest that abnormalities such as occlusal interference in the stomatognathic system induce functional abnormalities and that these affect both sympathetic and parasympathetic functions in the autonomic nervous system. One week after the removal of interference, each parameter had nearly recovered its pre-interference value. This suggests that normalization of the stomatognathic system is involved in the normalization of the autonomic function.
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高橋 裕, 川口 稔, 立井 大介, 稲永 昭彦, 宮崎 光治, 羽生 哲也
1996 年 40 巻 3 号 p.
442-447
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
The effect of the four types of surface treatment methods was evaluated to improve the bond strength between the self-curing acrylic resin and the abrasion-resistant plasticdenture teeth. All of the surface treatment methods significantly increased the bond strength. Specimens without surface treatment showed surface fractures after the bond test. As for the surface treatments using the silane coupling agent and 5% hydrofluoric acid-UDMA, most specimens showed surface fractures. The mechanically-roughened specimens (polished with # 100-SiC paper, sandblasted) showed cohesive fractures in self-curing acrylic resin. Although the bond strengths of specimens with or without surface treatment were significantly reduced after the thermocycle test (5, 000 cycles), most specimens that underwent the mechanical-roughening treatment showed cohesive fractures. The results of this study suggested that surface treatments of mechanicalroughening were effective methods to improve the bond strength and the bond durability of self-curing acrylic resin to occlusal surfaces of cross-linked abrasion-resistant plastic denture teeth.
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第1報予備調査結果
柏原 稔也, 市川 哲雄, 川本 苗子, 蟹谷 英生, 堀内 政信, 弘田 克彦, 三宅 洋一郎, 松本 直之
1996 年 40 巻 3 号 p.
448-453
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Dental treatment must meet the needs of the rapidly increasing elderly people in Japan. In addition, geriatric inpatients also increased with the increase of elderly people. Investigation was carried out to determine the oral condition and microflora in denture plaque of elderly patients in two geriatric hospitals and Tokushima Dental Hospital. The difference between healthy patients and geriatric inpatients was. discussed. The results of the preliminary survey were as follows:
1. Inpatients in a geriatric hospital were more elderly, and the frequency of edentulous patients was fairly high. The prognosis of the denture was poor because of high frequencies of low residual ridge and oral diskinesia.
2. Denture plaque of geriatric inpatients had the following characteristics compared to that of healthy elderly patients.
1) Numbers of total bacteria, Streptococci, Candida, and Staphylococci in isolated denture plaque of the geriatric inpatients were larger than those of healthy patients.
2) Linear relationships between numbers of total bacteria and Streptococci and between numbers of Candida and Staphylococci were found.
3) The frequency of MRSA in the geriatric inpatients was higher than in the healthy patients.
4) Numbers of total bacteria and Streptococci in denture plaque obtained in the inpatients with heart disease and cerebrovascular accident were much larger than those in the inpatients without these diseases.
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吉田 清彦, 兼平 治和
1996 年 40 巻 3 号 p.
454-458
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
An investigation was carried out on the influence of vibratory stimuli on mandibular position sense during opening and closing movements. Eight subjects were instructed to memorized 4 reference positions that were 5, 10, 15 and 20mm from the intercuspal position (ICP) using mandibular kinesiograph. Then they were required to open and close their mouths 20 times', and this was repeated from superior or inferior to reference position to reproduce memorized position with their eyes closed. Then a 100Hz vibratory stimulus was applied for 20 seconds to the mentalis and the above jaw movements were repeated. After application of stimulus from above (closing approach), the perceived mandibular position became lower than the reference position. On the other hand, from below (opening approach), it became significantly higher. Twenty experimental sequences were significantly changed. During movement, the vibratory stimulus effect disappeared in the early stage. It was found that the mandibular position sense was affected by vibratory stimuli. It was suggested that the muscle spindle played an important role as the neuronal mechanism controlling mandibular position.
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Hiding powerを指標とした不透明性の評価
里館 たまき, 永井 成美, 沢藤 太, 遠藤 忠治, 辰巳 浩輝, 多田 建造, 石橋 寛二
1996 年 40 巻 3 号 p.
459-463
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Translucency is a very important factor for obtaining an esthetic porcelain laminate veneer crown. This translucency is greatly affected by the opacity of the masking porcelain layer, but there is no objective criterion to evaluate the opacity. In general, opacity is well evaluated by hiding power. Therefore, hiding power of masking porcelain was calculated in this study using the ASTM (American Society for Testing and Materials) method.
The reflectance value of each masking porcelain sample containing 5, 10, 15, 20, 25, or 30% opacity of pink, white, yellow, and blue were measured with white and black backing, and hiding power was calculated using its scattering coefficients. Hiding power increased in proportion to the opacity and ranged from 100 to 1, 400 for any shade. Color difference dE between white and black backing increased rapidly under the 25% opacity.
It was concluded that (1) the opacity could be analyzed as hiding power and (2) hiding power under 20% opacity is very effective on visibility.
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第1報マスキングポーセレンの着色成分にオペークを用いた場合の色調構築精度
辰巳 浩輝, 永井 成美, 多田 建造, 沢藤 太, 角江 信彦, 伊藤 邦彦, 石橋 寛二, 村田 幸男
1996 年 40 巻 3 号 p.
464-469
発行日: 1996/06/01
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 an occlusal contact.
Since musking porcelain 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 using the Computer Color Matching (CCM) system to compensate opacity of musking porcelain. CCM sample is composed of three layers: surface layer, musking layer, discolored layer. CCM formulation for musking porcelain was calculated to give optimum color to the CCM sample. The formulation indicated the mixing ratio of the translucent (TL) and three kinds of opaques selected from 8 (white, yellow, blue, pink, gray, A1, A2, A3). In accordance with the CCM formulation, musking porcelain was baked and the CCM porcelain samples (underlaying layer + musking porcelain layer: 0.3mm+surface layer: 0.3mm) was made.
Compared to the target color and CCM sample, both reflectance curves are very similar and the color differences dE ranged from 2.0 to 4.0. Furtheremore, CCM sample showed the color to be indistinguishable from the target color by the naked eye.
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大島 浩, 畦崎 泰男, 宅間 巌, 池田 直也, 井上 宏, 南川 和彦, 杉原 富人, 中村 正明
1996 年 40 巻 3 号 p.
470-476
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
An investigation was carried out on the effect of hardened cements of tetracalcium phosphate and dicalcium phosphate dihydrate with 20-40%(w/w) citric acid solution (TeCP/DCPD) on the cell viability of L-929 cells and ROS-17 cells. The effects of commercial products such as cements containing hydroxyapatite (HAP) and tricalcium phosphate (TCP) were compared with those of TeCP/DCPD by using the neutral red assay and extraction method. Silicone rubber and zinc chloride were also included as a negative and positive controls respectively. The presence of TeCP/DCPD with 40% citric acid lowered the cell viability, and application of gelatin to and autoclaving TeDCPD with 40% citric acid kept the cell viability low. However, the cell viability obtained with TeCP/DCPD with 20 or 30% citric acid was similar to that obtained with of HAP, TCP or the negative control. These findings suggested that TeCP/DCPD can be used as bone graft material, however, further testing
in vivo is needed.
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今野 龍彦
1996 年 40 巻 3 号 p.
477-488
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Newly-developed all ceramic and metal ceramic crowns are alternatives to conventional porcelain jacket crowns (PJC) and porcelain fused to metal crowns (PFM).
Two types of metal ceramic crowns, made by sintering precious metals, were investigated as to adaptation and strength in clinical applications.
The results were as follows:
1. The prime factors in adaptation of crowns are the method of impression used for making a duplication die with the HERATEC (HT) system, and the method of applying the bonding agent between duplication die materials and the metal of the DEGUSINT (DG) system.
2. The strengths of these new metal ceramic crowns depend on the thickness of the sintered metal layer.
3. The strength of the HT crown is equal to the value of PJC and is one-third that of PFM, while the strength of the DG crown is two times that of the HT crown and the PJC and 0.7 times that of PFM.
4. To increase the strength of these new crowns, with the HT system, the thickness of the sintered metal layer and the mechanical strength of Au-Pd layer must be increased, and the number and the diameter of bubbles in the metal ceramic conjunction layer, should be decreased. With the DG system, it is necessary to increase the mechanical strength of the sintered metals. Thus it is necessary to investigate the sintering conditions.
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ダエット デメトリオ G.
1996 年 40 巻 3 号 p.
489-500
発行日: 1996/06/01
公開日: 2010/11/26
ジャーナル
フリー
The purpose of this study was to investigate the control mechanisms of jaw opening size and masticatory muscle activity affected by food bolus size and hardness in the early phase of mastication. Five healthy subjects participated in the study. Sphere-shaped gelatin with five different sizes and three different hardnesses were used.
Electromyographic activity (EMG) of bilateral masseter, anterior temporal muscles, and jaw movement were recorded simultaneously during mastication. Three-dimensional jaw opening size and integrated EMGs at each stroke was computed. Two-way ANOVA and Tukey test were used for statistical analysis.
The results indicated that the number of chewing strokes from ingestion to swallowing was significantly dependent on both food bolus size and hardness (p<0.05). Significant increase of jaw opening size at each chewing stroke in the early phase of mastication was observed for larger bolus sizes irrespective of food hardness (p<0.01). However, food hardness did not affect jaw opening size. Muscle activities were high for increasing bolus size and hardness. Significant differences (p<0.05) were observed in nearly all strokes for bolus size, but less for hardness. These findings suggested that jaw opening size and masticatory muscle activity was differently affected by food bolus size and hardness respectively.
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第2報裏装法の違いが衝撃緩衝能に与える影響
河野 文昭, 永尾 寛, 野田 正純, 岡 謙次, 友竹 偉則, 川端 修一, 松本 直之, 今 政幸, 浅岡 憲三
1996 年 40 巻 3 号 p.
501-507
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
A previous study demonstrated the efficacy of using soft denture liners to reduce impact forces on complete dentures and that a silicone denture liner had excellent shock absorption properties. The purpose of this study was to evaluate the influence of the design of soft denture liner placement on shock absorption properties of three soft denture liners using a free drop test and an accelerometer.
The results were as follows:
1. All three materials effectively reduced the impact force from 28.2 to 82.6% compared to that of denture base resin.
2. The design that had the soft denture liner extended to the peripheral of denture base resin 1 showed the greatest shock absorbing behavior for Kurepeet-Dough and Molloplast-B.
3. There was no significant difference in acceleration of Super Soft among the three lining designs.
4. The acceleration of all materials tested decreased with time.
5. The largest changes of the acceleration and rising time were observed on day 10 after being stored in distilled water at 37°C.
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折笠 史明, 松田 もと子, 永井 成美, 古川 良俊, 塩山 司, 石橋 寛二, 井上 昌幸
1996 年 40 巻 3 号 p.
508-511
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Patch test has been used to determine the existance of metal allergy, and the severity thereof has been determined by the change in skin color.
In order to obtain an accurate judgment of the change in skin color, the statistical formulation was calculated based on colorimetric investigation into 9 kinds of color characteristics: 1) Spectral reflectance curve, 2) Color difference, 3) Depth of shade, 4) CIE Lab-L
*, 5) CIE Lab-a
*, 6) CIE Lab-b
*, 7) Munsell-H, 8) Munsell-C, and 9) Munsell-V.
The rate of the agreement with statistical judgment and that of conventional subjective was 100% in positive reaction, and ranged from 90% to 94% in negative reaction.
In conclusion, the original statistical formulation based on colorimetric characteristics showed high level accuracy for determining the change in skin color reaction by the patch test.
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支台装置が異なる場合
鈴木 恭典, 大久保 力廣, 栗原 大介, 中山 昇, 青木 孝幸, 花谷 重守, 阿部 實, 宮田 孝義
1996 年 40 巻 3 号 p.
512-523
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Removable partial dentures should be designed to ensure efficient distribution of masticatory loads over the abutment teeth and alveolar ridge. The relationship between the denture stiffness and the various clasp designs on the pressure distribution to a single abutment tooth and the alveolar ridge was investigated in this study.
The results were as follows:
1. Regardless of the retainer designs, the pressure on the alveolar ridge was less when using a double structure than a skeleton type, and the pressure on the abutment tooth in the vertical direction was greater when supported by a double structure than a skeleton type.
2. When a Konus telescope was applied as a retainer the pressure on the abutment tooth in the vertical direction was greater than an Akers or an RPI clasp.
3. When an RPI clasp was applied as a retainer the amount of pressure on the alveolar ridge was maximum.
4. The pressure on the abutment tooth in the lateral direction showed a greater tendency when an Akers clasp was applied.
5. The displacement and strain of the denture were the least when a double structure design was applied.
6. When a double structure design with Konus telescope was applied, the displacement of the denture was the least.
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木戸 寿明
1996 年 40 巻 3 号 p.
524-534
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
The object of mastication is to crush food and form a swallowable food bolus. To comprehend masticatory function, it is essential to understand food behavior during mastication. However, there are almost no reports available there of.
The purpose of this study was to observe food behavior after food crushing and consider the association between food behavior and chewing patterns.
I designed a new method to estimate food behavior. Peanuts, which were chewed, were gathered separately from the buccal side and lingual side after varying numbers of chewing strokes, and then the amount and the degree of crushing of each peanut was measured. As subjects, twenty cases of chewing sides were selected, and food behavior and chewing patterns were measured. The results were as follows:
1. As mastication proceeded, the amount of broken peanuts on the buccal side decreased significantly and those on the lingual side increased gradually. In addition, the degree of crushing was higher on the lingual side than on the buccal side.
2. Food behavior was influenced by chewing patterns. The amount of peanuts on the lingual side was greater and the degree of crushing was less in case of Type III (compound type) than Types I (grinding type) and II (chopping type).
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松山 剛士
1996 年 40 巻 3 号 p.
535-543
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to confirm the existence of a rhythm for head movement during tapping movements, its coordination with jaw movements, and its functional significance.
A system that simultaneously tracks head and jaw movements was used.
Four normal adult males were selected as subjects.
The jaw range of motion and tapping frequency were designated according to tapping movements performed by the subjects.
During the experiment, the subjects' heads were not restrained.
The results were as follows:
1. During tapping movements, the head moved vertically and rhythmically, during jaw movements.
2. In average, the vertical range of head motion was about 6.5% of the range of jaw movement, and changes in the head's movement were proportional to those of the jaw.
3. The head moved in the opposite direction of jaw tapping movement, that is, when the jaw was in the opening phase the head moved upward, and when the jaw was in the closing phase the head moved downward.
4. It is considered that, in order to maintain balance and to smoothen functional jaw movement, the head moves cooperatively with the jaw.
5. Since head motion is considered as a cooperative and accompanying movement to that of the jaw, it may be affected by the conditions of jaw movement.
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中本 匡美, 玉本 光弘, 浜田 泰三
1996 年 40 巻 3 号 p.
544-550
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Denture plaque is an important factor in the pathogenesis of denture stomatitis.
Candida species can be found in high frequencies in denture plaque related to denture stomatitis. This study was carried out to investigate the antifungal activity and the effects on mechanical properties of dental materials of mouthwashes containing berberine hydrochloride, which has antifungal activity against
C. albicans, C. tropicalis, and
C. glabrata.
The results indicated that the mouthwashes containing berberine hydrochloride had antifungal activity (fungicidal activity and fungistatic activity with short-term exposure) and a slight effect on the color stability of acrylic resin plates, high wear resistance plastic teeth, and surface roughness of acrylic resin plates.
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伊藤 康子, 飯島 浩, 畑 好昭
1996 年 40 巻 3 号 p.
551-563
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to examine how various designs of coping affect the strength and stress distribution of the porcelain fused to castable ceramic (PFC) crowns. Four different coping designs and three types of crown were made:(Model 1) 1/3 of the labial cervical to the incisal;(Model 2) the labial to incisal;(Model 3) the labial to incisal, and 1/3 of the lingual;(Model 4) covering the entire labiolingual region.(Model 5) a castable ceramics crown; and (Model 6) a porcelain-fused-to-metal (PFM) crown.
All the models were subjected to destructive strength test and stress analysis using the finite element method (FEM), and the results were as follows:
1. When stress was applied to PFC crowns at 45° to the incisal region, the destructive strength tended to decrease as the porcelain-fused area increased. The destructive strength of Model 4 significantly decreased compared with the others when stress was applied to the center of the lingual at 45°.
2. FEM analysis showed that, in vital abutment teeth under four stress conditions, there were no marked differences in the tensile stress distribution and values among the different coping designs.
3. From the viewpoint of dynamics, Models 1 and 2 were considered to have the most desirable coping designs for PFC crowns.
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村松 瑞人
1996 年 40 巻 3 号 p.
564-573
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
The masticatory and neck muscles of some TMD patients may show spontaneous discharges on the electromyogram. The objective of this study was to clarify whether or not endurance clenching test (TEST) could evoke spontaneous discharges on the muscles of 18 subjects without TMD symptoms. Surface electromyography was taken to seek the spontaneous discharge just after the TEST and the TMD symptoms were examined.
The results were as follows:
1. The spontaneous discharge was evoked in 17 out of 18 subjects.
2. The average duration of the spontaneous discharge was: Masseter (M), 3.8 seconds (s); Anterior Teporal (Ta), 4.4 s; and Sternocleidomastoid muscle (SCM), 5.2 s.
3. The mean amplitude of the spontaneous discharge was: M, 227.1μV; Ta, 215.2μV; and SCM, 98.0μV.
4. The incidence of the spontaneous discharge in the muscles studied was: M, 63.9%; Ta, 69.4%; SCM, 55.6%.
5. Some TMD symptoms such as discomfort and/or spontaneous pain in the muscles were elicited by the TEST. All the symptoms disappeared within 48 hours after the experiment.
6. In almost all the muscles on which the spontaneous discharge was evoked, discomfort and/or spontaneous pain were felt and the onset of these symptoms occurred within 12 hours after the experiment.
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細菌学的検討
川本 苗子, 市川 哲雄, 蟹谷 英生, 柏原 稔也, 堀内 政信, 弘田 克彦, 三宅 洋一郎, 松本 直之
1996 年 40 巻 3 号 p.
574-579
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to investigate efficacies of acidic and neutral electrolyzed water as denture cleansers from the bacteriological aspect.
Twenty-five upper full dentures of patients of an elderly care center were used in this study. Nine dentures were immersed in acidic electrolyzed water, eight in neutral electrolyzed water and eight in denture cleanser (Pika
®). Plaque samples were collected from fitting surface of the dentures by scrubbing before and after immersion, and the changes in the number of bacteria were observed.
The results were as follows:
1. Acidic and neutral electrolyzed water were effective as denture cleansers, and the rates of removal [log
10 (bacteria number after immersion)/logic, (before immersion)] tended to be constant.
2. MRSA decreased by immersion in acidic electrolyzed water and in denture cleanser (MRSA was isolated from four dentures. Two were immersed in acidic electrolyzed water and two in denture cleanser).
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鈴木 政弘, 河野 正司, 野村 修一, 林 豊彦
1996 年 40 巻 3 号 p.
580-589
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Mandibular movements are produced by a combination of condylar rotation and translation of the condyle-disc assembly. A study on the relationship between these two components could clarify the pathosis of internal derangements of TMJ. In this study, to obtain basic information, the relationship between these two components was investigated during habitual closing movement of 19 normal subjects, especially marking the late phase. Movements were recorded with an optoelectric system, which can analyze mandibular movements in 6 degrees of freedom.
The results were as follows:
1. During closing late phase from 1 to 0.2 degree of rotation angle, the translatory ratio, i.e., the amount of condylar translation per degree of rotation angle, was small and constant, showing an average of 0.39-0.45 (S.D. 0.32-0.43) mm/degree.
2. During closing terminal phase from 0.2 to 0 degree of rotation angle, the translatory ratio increased abruptly, showing in average about 2.0 mm/degree. This result seems to be influenced by occlusal slide after occlusal contact, but the amount of condylar translation during this phase is actually small, showing an average of 0.40 ± 0.22 mm. This seems to be achieved by the fact that in normal subjects their condylar movement and intercuspal position are in harmony.
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村田 比呂司, 田口 則宏, 浜田 泰三, 二川 浩樹
1996 年 40 巻 3 号 p.
590-597
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
The purpose of this study was to evaluate dynamic viscoelastic properties of tissue conditioners using non-resonance forced vibration method. Four tissue conditioners were used. Measurements were carried out 2 hours and 7 days after mixing for each material. The complex modulus (G*), storage modulus of elasticity (G′), loss elasticity (G″), and loss tangent (tan δ) were determined at the frequencies of 0.01, 0.1, 1, 10, and 100 Hz and at different temperatures (20-70°) using a dynamic viscoelastometer. The results were as follows. The curves of G′, G″, and tan a according to frequency (0.01, 0.1, 1, 10, and 100 Hz) at different temperatures were superimposed to single master curves by the time-temperature superposition principle for each material. A wide range of G*, G′, G″, and tan δ was found among the four tissue conditioners. Flow properties of the four conditioners were found to reduce with time. The non-resonance forced vibration method is suited to determine dynamic viscoelastic properties of tissue conditioners.
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岡 謙次, 河野 文昭, 友竹 偉則, 今 政幸, 塙 隆夫, 浅岡 憲三, 松本 直之
1996 年 40 巻 3 号 p.
598-603
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Reinforcement and ion-exchange methods effectively strengthen the surface of dental porcelains. Both methods are applied to the surface for modification of the porcelain to generate residual compressive stress. These surface modifications may change the surface condition such as roughness and composition. However, the reliability of the strength and the effect of modification of the surface were not studied.
In this study, the apparent fracture toughness of the porcelains, which underwent ion-exchange, was measured by the indentation microfracture method, the reliability was analyzed by the Weibull distribution of the fracture toughness, and the relationship between the amount of leucite and compressive strength of the porcelain was considered.
Five commercial dental porcelains for metal ceramics were used. The parameters of the Weibull distribution ranged from 5.3 to 11.1, and no significant difference between the specimens undergoing ionexchange and the reference samples. It was found that the modification of the surface by ion-exchange increased the surface strength but did not affect the reliability of the porcelains.
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第2報看護職員の有床義歯に対する意識調査
森 宏樹, 谷 勅行, 関 雅寛, 田中 茂之, 倉持 信彦, 佐藤 貴映, 柳生 嘉博
1996 年 40 巻 3 号 p.
604-610
発行日: 1996/06/01
公開日: 2010/08/10
ジャーナル
フリー
Cleaning of the oral cavity and maintenance of oral hygiene can be very difficult for elderly patients confined to bed or hospitalized for medical care. It is very important how care-taking attendants and medical facilities are involved in the management of oral hygiene for such patients.
Questionnaires were given to dental maintenance nurses and care-taking attendants, responsible for the health management of hospitalized elderly patients, to investigate how well they were acquainted with plate dentures.
The results were as follows:
1. Nursing and care-taking staff members had frequent occasions, actually more frequent than imagined, of seeing or touching plate dentures.
2. Because of the nature of their work, almost all staff members had cleaned plate dentures. The methods were either self-taught or taught by their seniors.
3. They had little opportunity to acquire correct information on denture-related commodities and even dentures themselves. On the other hand, television broadcasts were found to have a tremendous amounts of influence.
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