Five-week-old rats of Wistar strain were given 1α-OH-D_3, an analogue of an active type vitamin D_3, 0.1μg/kg, 3 times a week, and its effect on the mandibular condyle, tibia epiphysis, and tibia metaphysis was examined radiologically and histopathologically. The results were as follows : I. Radiological findings 1). The compact osseous layer seen along the periphery of the mandibular condyle and the tibia epiphysis were hick from one week after the experiment, and bone trabeculae increased in number and were running compactly. The trabeculae of the mandibular condyle became narrower from two weeks after the experiment, while the trabeculae of the tibia epiphysis became narrows from three weeks after the experiment. 2) The bone trabeculae in the tibia metaphysis inceased in number and were running compactly from one week after the experiment. From three weeks after the experiment, the trabeculae became narrower. II. Histopathological findings 1). In the mandibular condyle one week after the experiment, increase in proliferative chondrocytes and hypertrophic chondrocytes made the cartilage layer thicker, and chondroclasts and erosion of calcified cartilage matrix decreased. Two and three weeks after the experiment, decrease in hypertrophic chondrocytes made the cartilage layer thinner, and chondroclassts and erosion of calcified caltilage matrix increased. Four weeks after the experiment, increase in hypertrophic chondrocytes made the cartilage layer thicker again, and chondroclats and erosion of clacified cartilage matrix decreased. Subchondral bone formation was always very active. Osteoclasts appeared two weeks after the experiment, and the trabeculage narrowed but were not seen four weeks after the expriment. 2) In the tibia epiphysis from one to three weeks after the experiment, decreased in hypertrophic chondrocytes made the cartilage layer thinner, and chondroclasts and erosion of calcified cartilarge matrix increased. Four weeks after the expriment, changes in the cartilarge layer, chondroclastes and erosion of calcified cartilage matrix were not observed. Subchondral bone formation was always very active. Osteoclasts appeares two weeks after the experiment and the trabeculae narrowed. 3) In the tibia metaphysis one week after the experiment, decrease in hypertrophic chondrocytes made the cartilage layer thinner, and increase in hypertrophic erosion of calcified cartilage matrix was observed until three weeks after the start. Intrachondral bone formation was always very active. Osteoclasts appeared two weeks after the experiment, and the trabeculae narrowed. 4) Scanning-electron-microscopically, in the mandibular condyle and tibia epiphysis, calcospherites in the chondrocyte lacunae became sparse with time, but they were dense again in the mandibular condyle four weeks after the experiment. On the basis of the foregoing findings, administration of 1α-OH-D_3 was found to accelerate bone formation in the mandibular condyle, tibia epiphysis, and tibia metaphysis. As for growth of cartilaginous tissue, the mandibular condyle showed more complex changes than the tibia epiphysis or tibia metaphysis. On the basis of changes in apperance of osteoclasts, the mandibular condyle showed better bone formation.

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The occlusal surface of a complete denture is closely related with stability and masticatory function of the denture, and the surface must be formed in harmony with mandibular movement and is generally adjusted by grinding on an articulator with condylar path regulated on it. However, contact with food and the opposing teeth after insertion of the denture gradually causes abrasion of artificial teeth, and occlusal facets are enlarged and their forms change. Therefore, observation of complete dentures with good prognosis was made, and changes by abrasion in projected area of occlusal plane and in inclination angle of protrusive facet were examined. The results were as follows : 1. The cases of porcelain teeth used at the molar region and those of acrylic resin teeth showed severe abrasion to about the 3rd and 4th months, and the rate of increase decreased thereafter. Abrasion after the 12th month in the cases of porcelain teeth rarely progressed and was stabilized. In contrast, the cases of acrylic resin teeth showed still continuing abrasion at the 12th and 24th months and about twice the abrasion at the 24th month as compared with the porcelain teeth. 2. Protrusive and retrusive facets showed a high change in 5 to 6 months of about 60% of the abrasion resulted by the 24th month. Against this, balancing facet showed abrasion of this extent in 3 to 4 months. The increasing trend in both cases declined thereafter. Thus, balancing facet tended to stabilize earlier than protrusive or retrusive facet. 3. Examination of projected area index for the 24th month of occlusal facets showed no significant statistical difference for the upper and lower jaws, right and left sides, and functional and non-functional cusps. Although no significant statistical difference was found, protrusive facet tended to show higher values than retrusive facet. Protrusive facet showed significantly higher values than balancing facet. No significant difference was found between the premolar and molar regions, but the anterior teeth region showed significantly higher values than the premolar or molar region. 4. Examination by region of inclination angle for the 24th month of protrusive facet showed that the angles became smaller from the anterior teeth region to the molar region. Examination by region between semi-anatomical artificial teeth and functional artificial teeth showed that the angles for semi-anatomical artificial teeth became smaller towards the posterior region from the anterior teeth region to the premolar region, and to the molar region. For functional artificial teeth, the anterior teeth region showed significantly greater angles than the premolar or the molar regions. However, no significant statistical difference was found between the premolar and molar regions. 5. Examination of changes with time in inclination angle of protrusive facet showed a slight increasing trend for the anterior teeth group and a slight decreasing trend for the molar group. However, little change was seen after 24 months. 6. Occlusal facets of complete dentures after 24 months showed considerable abrasion as compared with those at the time of insertion. On the other hand, inclination angle of protrusive facet showed little change. On the basis of the foregoing findings, the inclined plane of occlusal facets is thought to guide functional jaw movement when the occlusal facets are formed properly in harmony with their function.

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Department of Preventive Dentistry, Kyushu Dental College has been conducting physical anthropological studies of the oral cavity in various areas of Japan and a neighboring country. These studies indicated racial and regional differences in the morphology of the dental arch and palate. This study describes the dental arch and the palatal traits in Taiwanese females. Eighty-nine Taiwanese females 18 to 24 years old and 212 Japanese females (Kitakyushu), as a control, had impression taken and plaster models made. The measurements were made on the models. The date of Taiwanese females were also compared with those of Japanese females (Okinawa) and Taiwan aboriginal females (Paiwan, Rukai, Atayal and Ami tribes) obtained in other investigations. The length of the dental arch in Taiwanese females tended to be shorter than that of Japanese females (Kitakyushu and Okinawa) and Atayal females, but tended to be longer than those of Paiwan, Rukai and Ami females. The breadth of the dental arch in Taiwanese females tended to be greater than in those of Japanese females (Kitakyushu and Okinawa) and Paiwan females, but smaller than those of Rukai, Atayal and Ami females. The height of the palate tended to be smaller in Taiwanese females than those of Japanese females (Kitakyushu and Okinawa), Paiwan and Rukai females. These findings indicate that the morphology of the dental arch and palate in Taiwanese females differs from that of Japanese and Taiwan aboriginal females.

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In periodontal disease, it seemes that non-specific defense-response and specific immuno-response play important roles. Peritoneal macrophages were induced by the injection of E. coli and of LPS, and were studied in their development in the non-specific response and the specific response. The activity of phagocytosis of sheep red blood cells by the macrophages and the positiveness of several IgG subclass-Fc receptors (-FcRs) and of Ia antigen on the macrophages were measured. The results were as follows : 1. The phagocytosis by the E. coli-induced macrophage was more frequent on 1st, 3rd and 7th days than that by the LPS-induced macrophage. 2. The positiveness of IgG subclass-FcRs on the E. coli-induced macrophage was higher than that on the LPS-induced macrophage. 3. The positiveness of IgG subclass-FcRs decreased in the order IgG1, IgG2b, and IgG2a in the two macrophages through 7 days. In the LPS-induced macrophage, the positiveness of IgG1-FcR was 3 to 5 fold of that of IgG2a-FcR. In the E. coli-induced macrophage, the positiveness of IgG1-FcR was 7 to 10 fold of that of IgG2a-FcR. 4. In the measurement by cytotoxic test, the positiveness of Ia antigen on the E. coli-induced macrophage was higher than that in the LPS-induced macrophage. In the two macrophages the positiveness increased from 1st to 3rd days, and decreased thereafter. 5. In the measurement by enzyme-linked immunosorbent assay, the positiveness of Ia antigen on the two macrophaes increased from 1st to 3re days, and decreased on 5th day. The positiveness on the E. coli-induced macrophage was higher than that on the LPS-induced macrophage. In short, the E. coli-induced macrophage was higher in the activity of phagocytosis and in the positiveness of IgG subclass-FcRs and of Ia antigen than the LPS-indused macrophage. It seemes that the FcR positive macrophages gradually increase in phagocytotic activity, and finally express Ia antigen. Induced macrophages by antigen-injection possibly increase in non-specific phagocytotic activity at first, and then this phagocytosis provide specific immuno-response such as Ia antigen.

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Radiation hazard of the mandible often occurs after radiation therapy for oral cancer. Much literature about mandibular radiation hazards has been written since Regaud first reported a case of radiation hazard of the mandible in 1922. However, genesis of the radiation hazard of the mandible has never been resolved. It is generally thought that a high radiation dose causes the mandibular radiation hazard, and the tooth extraction after radiation therapy might accelerate the radiation hazard of the mandible. There are many theories about the influence of tooth extraction following radiation therapy to the mandible. The purpose of this study is to investigate the influence of the tooth extraction after irradiation to the mandible experimentally. The following results were obtained. 1. In a group whose teeth were extracted immediately after irradiation, healing of the extraction wound was delayed. However, severe radiation hazard was not recognized macroscopically. 2. In a group whose teeth were extracted after 2 weeks following irradiation, radiation osteomyelitis was recognized macroscopically. All of these cases showed disturbances of healing of the extraction wound. 3. The early radiographical finding on the mandible, in which the teeth had been extracted after irradiation, was osteoporosis and it was accelerated by infection. 4. Bone resorption caused by osteoclast was observed microscopically in a group whose teeth were extracted after irradiation. Osteoporotic bone resorption was accelerated by infection, and was decreased by subsidings of infection and blood vessel hazard. 5. Sequestration was one of the results of radiation osteomyelitis, which was caused by the disturbance of blood circulation due to periosteum detachment. Sequestrum was caused by invasion of the healthy gingiva. 6. Though healing of the extraction wound was delayed by irradiation, new bone was formed in the alveolar socket if the blood clot occupied the alveolar socket. 7. Radiation hazard of the mandible became more severe when the mandible was accompanied by infection.

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Saliva secreted in response to α_1-adrenergic and cholinergic receptor agonists such as methoxamine (Methox), α-methylnoradrenaline, and pilocarpine (Pilo) was collected from the cannulated ducts of parotid glands of both male and female rats from 4 to 10 weeks and 3.5, 8, and 15 months of age. It was analyzed for volume, for the concentrations of protein, potassium, calcium, inorganic phosphate, and amino acid residues, and for the types of proteins, amylase activity and isozymes. After the collection of saliva, the parotid glands were carefully removed and weighed. The wet weights of the glands increased substantially up to 8 weeks of age and then reached almost plateau values and finally tended to decrease at 15 months of age in both sexes. The salivary volumes secreted in response to Methox and Pilo were positively correlated with the parotid gland weights in both sexes. The concentrations of protein, potassium, and inorganic phosphate were inversely related to the salivary flow rates only at relatively low rates of flow in contrast that the amylase activity was positively correlated with the concentration of protein independent of the nature of the stimulus, age, and sex. In the α_1-adrenoceptor stimulation, the amylase activity was positively correlated with the concentration of calcium independent of age and sex. The types of protein, amino acid residues, and amylase isozymes did not show a great deal of differences at least qualitatively independent of the nature of the stimulus, age, and sex from 4 weeks up to 15 months of age. However, in parotid saliva of several rats at 8 and 15 months of age, the abnormal proteins were electrophoretically observed independent of the nature of the stimulus and sex. The relatively low molecular proteins in parotid saliva were selectively adhered to the resin plate regardless of the types of plate without polishing procedures in only dry states. Thus, it was conclusively elucidated that the secretory function of both α_1-adrenergic and cholinergic receptors in the parotid glands of rats was complete at early stages and intact up to 15 months of age although some exceptions were observed in the protein secretion at elderly stages.

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The functional forces depending on the bite, tongue and cheek, and the artificial forces caused by the prosthetic or orthodontic mechanism are absorbed by the periodontal ligament. The dental root surface area is closely related to support of the periodontal ligament. The same applies to the shape of the root, the attachment direction and the implanted condition. Few reports, however, have been made on the subject of the measurements of the root surface area. We devised a new method to measure the root surface area using computer analysis of the moire, and gained the following conclusions ; 1) The dental root surface area along with the computer analysis of the moire was determined without damaging the teeth. 2) The sectional interval was reduced by the moire and the precision was increased. 3) The method using the moire and computer is superior in working capacity compared with past methods.

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At present many brands of denture retainer materials are on the market. Although they seem to be different from each other in physical and mechanical properties, there are no fundamental criteria for choosing a material. In the present study, therefore, characteristics of four available powder type denture retainer materials were examined through sensuous evaluations such as smell, taste, and cleaning, and observation of physical characteristics such as pH and viscosity. The results were as follows : 1. On sensuous evaluations, Faston and Corega were undesirable from the viewpoint of smell and taste ; Zanfton and Corega were undesirable from the viewpoint of cleaning. 2. On the measurement of pH, Faston indicated acidity, so it was suggested that Faston may affect the oral mucosa. 3. Although viscosity of four denture retainer materials showed considerable variation from each other, appropriate degrees of viscosity for denture retainer materials could not be determined.

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この研究は, 種子島住民の歯列弓, 口蓋の諸形質を明らかにする目的で行なわれた.資料採取した133名のうち, 16歳以上で正常歯列を有し, しかも歯冠崩壊の程度が軽い者43名について石膏模型上で計測を行なった.その結果, 種子島住民の歯列弓の長径は, 甑島住民よりやや長い傾向にあるが, 男では沖縄住民と, 女では長島住民と非常に近似していた.歯列弓の幅径では, これら近隣諸島住民よりやや広く, また, 口蓋の深さは長島, 沖縄住民と若干異なった所見を呈しており, 種子島住民の口腔形質には地域的特徴が示された.

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抜去されたヒトの上顎前歯10歯を用い, 手用器械によるリーミングとファイリングの場合と, それに超音波振動を併用した場合の根管壁の拡大, 清掃効果を知る目的で実験を行なった.これら, 2通りの方法で得られた試料を走査電顕で観察した結果, 手用器械(Kファイル)により拡大, 清掃された根管壁は, 根管の歯冠側, 中央部, 根尖部ともかなり厚いsmeared layerに覆われており, 象牙細管の開口部は観察できなかった.超音波振動により拡大, 清掃された根管壁は, 根管中央部では部分的にsmeared layerが除去され象牙細管の開口部がみられたが, 歯冠側と根尖部では観察されなかった.手用器械だけの場合と超音波振動を併用した場合で根管壁の状態を比較すると, 根管壁全面についてみるならば, 超音波振動を併用したときの方が良好な状態であった.しかしながら, 根管治療や根管充填の成否にとって重要な部位である根尖部のその状態は, この両手法には特に異なる所見は認められなかった.このことは, 根管拡大および清掃の術式に新たな手法の考察が必要であることを示唆している.

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Enlarging and cleansing of the root canal is key requirements for successful root canal preparation. The purpose of this study was to evaluate the efficiency of enlarging and cleansing root canal by the ultrasonic energized filing and by conventional hand filing. Extracted human anterior teeth (twenty teeth) with the root canals untreated were prepared by the two methods and the surfaces of the prepared canal walls were examined with the scanning electron microscope. The results were as follows : 1. The working time for the preparation of root canal from #15 K-file to #50 K-file was shorter by the conventional method as compared to the ultrasonic method, and significant differences were found statistically. 2. The surfaces of the canal walls prepared by the conventional method were covered with a smeared layer and the opennings to the dentinal tubules were not observed. 3. Characteristic diagonal wave patterns of grooving were found in the surfaces of the canal walls in the middle area prepared by the ultrasonic method, but surfaces of the canal walls in the middle and apical areas were covered with a smeared layer and the opennings to the dentinal tubules were not observed. 4. There was no difference in the appearance of the root canal walls when these ultrasonic and conventional hand methods were compared. 5. A few inaccesible parts existed in both groups ; therefore, these parts need to be cleansed.

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A case reported of Pleomorphic-adenoma arising in the left soft palate of a 43-year-old female. The patient complained that she had suffering from swelling in her left soft palate for 20 years. An elastic hard tumor, the size of the tip of a thumb without adhesion to the surrounding tissues, was found in the first-visit examination. An en-block resection of the tumor was performed under clinical diagnosis of a benign tumor. Microscopiccally, the tumor showed proliferation of glandular epithelial cells forming duct-like structures containing an eosinophilic secretion, and three pieces of calcified mass. Histopathological diagnosis was benign preomorphic-adenoma with calcified masses. These calcified masses in this tumor were thought to have been by degeneratin of the stroma tissues of the tumor.

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有床義歯とくに総義歯作製に際してフランジ・テクニックを応用する場合, 筋圧中立帯を採得しなければならない.通常, 筋圧中立帯の採得にはワックスが用いられるが, ワックスの軟化温度, 操作時間, 機能運動の種類や強さなどによりその形態は様々の影響を受ける.今回著者らは, 筋圧中立帯の形態に影響を及ぼす因子について着目し, ワックスの温度特性について検討することにした.まず室温(25℃)から操作温度(47℃)までの, ワックスの表面温度と内部温度の経時的変化を観察したところ, 表面温度が47℃に達するには6∿8分, 内部温度が47℃に達するには7∿8.5分を要した.この値より, 臨床で筋圧中立帯の採得を行うには, 採得前に9分程度ウォーターバス中に浸漬しておく必要があると思われる.つぎに, 操作温度から口腔内温度(37℃)までのワックスの表面温度と内部温度の経時的変化を観察したところ, 表面温度が37℃に達するには9∿10分, 内部温度が37℃に達するには10∿11.5分を要した.さらに, 47℃から37℃までを2℃ずつの6段階に分けて, ワックスの圧縮率を調べたところ, 空嚥下時の大臼歯部舌圧を想定した荷重(60g/cm^2)を加えた場合には, 45℃まではほぼ100%の圧縮率を示したが, 温度低下に伴い低下し, 37℃ではほぼ92.0%であった.また, 空嚥下時の小臼歯部舌圧を想定した荷重(21g/cm^2)を加えた場合には, 47℃では97.2%の圧縮率を示したものの, 温度低下に伴い急激に低下し, 37℃では47.8%の圧縮率しか示さなかった.このように, 軟化温度や加える荷重の大きさがワックスの可塑性に影響を与えることがわかった.

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