The teeth will stop erupting and stabilize when they erupt and come to occlude with each other. So if a tooth fails to occlude, it will extrude beyond the occlusal line. But it will be intruded if it is crowned above the occlusal level. These phenomena suggest us that the occlusal contacts of the upper and lower teeth play an important part in stabilizing the vertical position of the teeth. Nevertheless, the true status has not been explained in detail. To make it more clear, I tried to find the change in the occlusal contact duration due to the increase of vertical dimension. For this, I had ten subjccts and each subject was worn his own bite plate on. And I measured the occlusal contact duration (total and respective) and frequency when the vertical dimension from the centric occlusion was increased temporally, ranging from 1mm to 5mm. The results were as follows : 1. The occlusal contact duration increased as the vertical dimension increased, and increased greatly especially when the dimensional change was over his own free way space. 2. The occlusal contact frequency increased, too, as the vertical dimension did, but decreased when the dimensional change was over his own free way space. 3. As for respective occlusal contact duration, the percentage of short contact duration decreased as the vertical dimension increased, and long contacts increased. The results mentioned above tell us that the upper and lower teeth are stabilized without any overeruption or depression by repeating a proper contact, and the balanced occlusion is maintained by means of muscles controlling the position and movement of the mandible. Therefore, it can be said that the teeth are depressed and the original vertical dimension is re-established, even if the vertical dimension is increased by a orthodontic treatment, without the muscular adaptation. So it may be concluded that the increase of the occlusal contact duration mainly cause the relapse of the vertical dimension.

抄録全体を表示

It dates back more than 40 years ago that acrylic resin was introduced to the field of clinical dentistry. During these 40 years, a variety of resin materials such as self curing resin, heat shock resin and pour resin were newly developed, and many investigations were also undertaken in pursuit of most faverable imbedding (core making) and heating cycle. In the present paper, a series of experiments was described which compared the inner stress as produced in the curing process of different procedures of core making. Results were summarized as follows : 1) Production of inner stress was minimum at initial stage of mixing of resin when it was fluid, so that most of the inner stress was to be produced after the resin became rigid to certain extent. 2) The value for the specific volume measured after polymerization was lower with the heat curing type resin than with the self curing resin, while the Tg measured for the former was higher than that for the latter resin. 3) The specific volume measured on resins as polymerized by the silicone core method gave smaller values as compared with that resins polymerized by the plaster core method, and Tg was higher the former type resins than the latter ones. 4) When Cast Resin (pour resin) was used for experiment, the specific volume obtained was smaller than that obtained in the press type, while Tg obtained was not affected in the least with use of this resin. 5) Measurment on the dimensional accuracy showed better result with use of self curing resin than with heat curing type resin, and the rate of shrincage with the former type resin was within the range between 1/2 to 1/3 of that with the latter, in spite that plaster imbedding or silicone core methods were applied. 6) When polymerized resins were kept at high temperatures, release of the inner stress was faster and deformation much greater. 7) The self curing resins as polymerized by the plaster core method exhibited lower values of Tg and greater specific volumes, though the dimensional accuracy was excellent. An improvement on the polymerizing method (silicone core method), however, proved to be able to raise the value of Tg as well as lower the value of specific volume with the self curing resin. 8) As stated above, the silicone core method was more advantageous for improving the respective value of Tg and specific volume, although disadvantageous in point of dimensional accuracy. 9) It was shown that the inner stresses were produced to a greater extent with the heat curing type resins than the self curing ones.

抄録全体を表示

The zinc, cadmium and arsenic concentrations in normal teeth which were obtained randomly from the Kitakyushu area, Takachiho area and Tsushima area, were quantitatively determined by atomic absorption spectrophotometry on a basis of dry weight. The results of the experiments were as follows : 1) The mean values of trace metal concentrations in 123 teeth from the Kitakyushu area were 171.96 μg/g of zinc, 0.55μg/g of cadmium and 0.26μg/g of arsenic. 2) The mean values of trace metal concentrations in 35 teeth, obtained from the healthy subjects in the Takachiho area, were 194.91μg/g of zinc, 0.76μg/g of cadmium and 0.77μg/g of arsenic. These percentages were significantly higher than those of the Kitakyushu area. 3) The mean values of trace metal concentrations in 12 teeth, obtained from the chronic As-disease in the Takachiho area, were 269.91μg/g of zinc, 1.31μg/g of cadmium and 1.65μg/g of arsenic. These levels were significantly higher than those of the healthy subjects in the Takachiho area. 4) The mean values of trace metal concentrations in 3 teeth from the Tsushima area were 167.55μg/g of zinc, 0.50μg/g of cadmium and 0.52μg/g of arsenic. 5) The mean values of zinc, cadmium and arsenic concentrations taken from various age were observed to be generally higher in the Takachiho area when compared to those of the same age groups in the Kitakyushu area and Tsushima area. 6) The Cd/Zn ratio and As/Zn ratio of teeth, obtained from the chronic As-disease in the Takachiho area, were significantly higher than those of teeth in other groups. In conclusion, the environmental pollution in the Takachiho area has relatively high levels of arsenic concentration. However, this could be considered partial offset by comparatively high levels of cadmium, zinc and another metals concentrations, too.

抄録全体を表示

A biological study was undertaken on the correlationship possibly existing between the tooth stump remaining in the mandible and its neighboring tissues. Tooth stumps were prepared in dogs as experimental animal from both vital teeth and non-vital filled teeth, and longitudinal observations ware made patho-histologically for possible changes occurring in the tooth stump and its periphery. Results were summarized as follows. 1) After preparation of the tooth stumps, some remained in the original site, while others moved toward the oral direction and some of these came to show the amputated end in the mouth. This movement of the stumps largely depends on the extent of injuries to which the neighboring tissues suffered and other various factors. 2) In early stages of post operation, there was always inflammatory symptom seen in the periphery of stumps. The intensity of the inflammation also depends greatly on the severity of surgical attack given to any tooth. The inflammation disappeared sooner when it dealt with the stump containing the vital pulp and when the surgical attack for preparing the stump was mild. In the cases where the stump contained necrotic pulp or was treated with root filling material, these continued to irritate the tissues and prolong the inflammation considerably. 3) Regeneration of bone tissues at the site where the tooth was separated from its root began earlier or later depending on the severity of surgical attack given. Regeneration of bone was also affected by the kind of root filling materials used in the experiment and further by such factor as death or life of the tooth pulp involved. When regeneration of bone was retarded traveling of the stump became greater. 4) There were often observed resorption occurring in the periphery of stump. The resorption may have been caused as results of pathologic change of the root stump into foreign body or as consequence of inflammation which occurred in the stump's peripheral tissues. This phenomenon was seen more frequently in root-filled teeth. 5) Apposition of cementum substance on the stump surface was frequently observed. This may be related to increased proliferative drive in the tissues near the focus of inflammation on one hand, but there may also be operating an effect of uncontroled activity on the side of cementoblast cells as resulted from abolition of occluding function. 6) The apposition of cementum on the surface of cut end of stump may be seen in those cases where dense connective tissues resembling those of periodontal membrane have covered the part adjoining stump's cut end. 7) Among the experimental tooth stumps containing vital pulps, some lost their pulps in necrosis and others kept them intact. The necrosis occurred most frequently in those cases where the surgical attack was severe, accompanying severe inflammation. In cases of stump where the pulp was kept in vital state and where no sign of movement was noticed with the stump itself, the pulp was considered to be keeping a vital communication with the periodontal membrane through the apical foramen, and the periodontal membrane was considered to be playing its biological role in detaining the stump on the spot. 8) The periodontal membrane remaining around the tooth stump was shown to have suffered certain destructive changes due to inflammation, and there occurred even some degenerative symptoms such as hyaline degeneration. It may be generally stated that severer the pathologic change of periodontal membrane, greater the movement of the tooth stump, suggesting that there existed a distinct correlationship between the appearance of periodontal membrane and the tooth stump as buried in the mandible. 9) On the other hand, however, there were frequent instances of stumps which were intimately connected with periodontal membrance in spite of the fact that they were moved in considerable distances. Around the surface of these

(View PDF for the rest of the abstract.)

抄録全体を表示

In regard to study in the malignant tumor, the changes nerve fiber in human cancer and in experimentation tumor has been put foward several theories, in other word, the previous report on nerve fibers in malignant tumor, there have been non-nerve distribution and conversely, there have been regenerated nerve fibers which have had influence upon the growth of tumors, the consensus has not yet been resolved. The author has studied nerve distribution in oral cancer tissues that operated by First Department of Oral Surgery Kyushu Dental College. In addition, oral tumor experimentation conducted by transplanting Vx7 carcinoma in the buccal region in rabbits to study the nerve fibers in the tumor. The following results were obtained. 1. On the nerve distribution, normal nerve fibers and degenerated nerve fibers were observed in the malignant tumors (nest, stroma). Normal nerve fiber could be found running far from or near the nest, nerve fibers that goes nest. Some nerve fibers that runs at times ramifies in stroma and comes to the nerve ending. The distinctive feature was that, some nerve distribution are traced along soft connective tissues around the cell group of the tumor, there imagined as if it resists infiltration of the tumor cell or as if by- passing it. 2. On the nerve number and size, normal nerve existed in stroma than in the nest. The experimental result made clear that the growth of the tumor and these nerve fibers are destroyed by the tumor cell. The sizes varied from simple nerve fibers or nerve fiber bundles, there are destroyed by the tumor cell in the early stages are not clear. 3. On the nerve ending and network, in the nest or stroma, ramifying simple free nerve ending were evident, however, no special nerve ending or network was found. The author believes that the special nerve endings or network are destroyed in an early stage and disappear from the tumor tissues. 4. On the neuro-vascular relationship, in the stroma blood vessels and capillaries are scattered but nerve fibers were accompanied by these a few blood vessels and capillaries. It is called neuro-vascular movement. 5. On the nerve degeneration, degenerated nerve fibers in malignant tumors have been found more in the nest than in stroma. The degeneration of stroma is mainly the deterioration of dyeing, swelling and creeping. With the malignant tumor outbreak, when connective tissue of the stroma starts to grow, a slight degeneration occurs. The degeneration characteristies of the nest are the strong creeping, hyperplasy, swelling, severance, vacuolar degeneration, granular degeneration, dissipation. As mentioned above the nerve fibers in malignant tumors undergo various changes. So the normal nerve fibers in tumors are proper nerve fibers or regeneration nerves, or whether they are causing some sort of affect upon the tumor is still doutful. It is difficult to determine through this study, but it is obvious that the active normal nerve fibers exist without being affected by tumor cell.

抄録全体を表示

The experiment, employing histochemical methods, was undertaken to discern the distribution of phosphatases in the taste buds of the fungiform papillae, foliate papillae and vallate papillae of normal rat's tongue. The phosphatase activity was compared with that in rats after exposuing the tongue to gymnemic acid, a taste modifier which suppresses sweetness and to that in rats with degenerating taste buds following bilateral transection of the chorda tympani and glossopharyngeal nerve. 1. Distribution of phosphatases in the normal papillae A. Alkaline phosphatase activity was not present on the superficial epithelium of fungiform papillae except on the top of some fungiform papillae. Intense alkaline phosphatase activity was present in the superficial layers of the taste bud-bearing epithelium of the foliate and vallate papillae. Taste bud cells had, in general, no activity but occasional cells did have a slight reaction. B. Acid phosphatase activity was present in the taste buds of all papillae. Intense reaction was localized in the supranuclear cytoplasm of the taste bud cells with a variation in each taste bud cell. C. Adenosine triphosphatase activity was present in the taste buds of all papillae. Intense activity was found on the cell membrane and at the taste pores. 2. Distribution of phosphatases in the papillae affected by gymnemic acid A. All papillae showed the same alkaline phosphatase activity at that in the normal papillae. B. All papillae showed the same acid phosphatase activity as that in the normal papillae. C. The foliate and vallate papillae showed the same adenosine triphoshatase activity, but it was found that the activity decreased on the taste cell membrane of the fungiform papillae and showed no clear boundary of the taste bud cells. This suggested that gymnemic acid might have an effect on adenosine triphosphatase activity, therefore, this might be one of the causes for suppression of sweet sensitivity by gymnemic acid. 3. Distribution of phosphatases in the papillae following bilateral chorda tympani and glossopharyngeal nerve transection The taste buds in foliate and vallate papillae were reduced in width four days after denervation and in length five days after denervation. In addition, the taste pores disappeared and the basal cells proliferated at the basal areas of the degenerated taste buds, following replacement by squamous epithelium. A. Alkaline phosphatase activity was not positive on the superficial epithelium of fungiform papillae on the fifth postoperative day. There was virtually an increase of reaction zone in width for the alkaline phosphatase activity of the superficial layers of the stratified squamous epithelium containing the taste buds of foliate and vallate papillae from three days to four days after denervation and there was a slow decrease in width for alkaline phosphatase activity. Alkaline phosphatase activity persisted even on the ninth day after denervation. B. Acid phosphatase activity increased in intensity following the progressive degeneration of the taste buds. Intense activity was found even in the infranuclear cytoplasm of the taste bud cells indicating the same intensity in the cells. C. Adenosine triphosphatase activity decreased in intensity on the cell membrane of the taste buds three days after denervation and showed the same activity in the taste buds. Thereafter, the activity decreased in intensity. This suggested that adenosine triphosphatase was most affected by denervation. The results of the present experiment showed that adenosine triphosphatase did play a significant role in the perception of taste-stimulus and maintenance of the taste buds. This might partially prove that the enzymes are related to the mechanism of taste.

抄録全体を表示

顎関節に原発した腫瘍の報告は少なく, かつ軟骨腫の症例は極めて少ないと言われている.今回我々は, 左顎関節部に発生した軟骨腫の1例を経験したので報告する.患者は36才男性で, 開口障害および左顎関節部の鈍痛を主訴として来院した.顔貌は左右非対称で, 左顎関節相当部位に骨様硬度を有する拇指頭大の膨隆を認める.この膨隆は, 顎運動時左関節突起に付随して動き, 最大開口時顎の左方偏位を認める.X線的には, 左関節頭に拇指頭大の不均一な不透過像を認め, 関節突起は変形しているが関節窩, 関節結節の変形は認めず周囲骨との境界は明瞭である.入院後, 全身麻酔下にて腫瘍摘出手術を行なった.腫瘍は被膜でおおわれ周囲組織との境界は明瞭で, 関節頭に癒着しており関節頭と伴に一塊として摘出した.摘出物は, 比較的小型で異型性の少ない単核の軟骨細胞が散在し, 関節頭骨髓腔内にも充実性に増殖して存在しているが, 軟骨細胞の異型性は認められない.以上の所見より軟骨腫と診断した.現在まで報告された本部における顎関節突起に発生した骨原性腫瘍のうち, 軟骨性腫瘍の報告は軟骨腫1例, 骨軟骨腫1例, 軟腫芽細胞腫1例である.したがって本症例は本邦における顎関節突起に発生した軟骨腫としてきわめて稀な症例である.

抄録全体を表示