Recently research interest is being focused on the role of the L-form variety of Staphylococcus aureus derived from human mouth as to whether or not they were involved in the initiation and maintenance of chronic infections occurring in the oral region. Using the strain 131-1 of Staphylococcus aureus isolated from human mouth, we have carry undertaken to out a series of basic studies on the induction of organism to its L-form by exposure to Penicillin G or its reversion, and, utilizing the induced organisms, drug sensibility was examined, and, particularly, the cytopathological significance was studied with L-form organisms with use of tissue cell culture. Results obtained were summarized as follows. 1. Penicillin induction of L-form colonies of Staphylococcus aureus 131-1 was achieved in 3 to 4 days usiug the solid culture medium for L-form. 2. When the strain 131-1 of staphylococcus was grown in the L-form liquid medium for 4 to 5 days, proliferation of L-form colonies proceeded to the extent that they could be readily recognized by inspection. (the naked eye) 3. Experiments by minifiltration conducted on the growing L-form organisms in the liquid media confirmed that the minimum unit of bacterial growth size was below 0.45 micron. 4. The growth of the L-form organisms in the liquid media reached peak by 48 hours, which was slowed down with successive days. 5. Drug sensibility tests were carried out both for the strain 131-1 staphylococci and their L-form organisms, and the results showed that the latter showed higher resistance than the mother strain against some agents that inhibit the synthesis of bacterial cell wall. 6. The L-form organlsms could be recovered from the pus derived from chronic lesions in the mouth such as gingivitis and periodontitis in amount as much as 25%. 7. The L-form organisms were distributed 2-fold more abundantly in the pus from periodontitis lesions than from gingivitis lesions. 8. Observations on the possible cytopathic effect of the L-form organisms disseminated in the tissue cell culture revealed that 2 hours were sufficient to produce degeneration of the cell.

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The spill-way-more precisely the spill-groove-has always been prepared on the occlusal surface of artificial tooth for decreasing the chewing pressure and making the food flow more easily. But, the flow mechanism in the spill-groove has ever scarcely been elucidated. The author tried to make clear the flow mechanism in the spill-groove by creep and forced compression test for three kinds of viscoelastic materials. In the creep test, the eight types of metal penetrators were used. The results were as follows : (1) In the creep test, the relative strain obtained by a penetrator having a narrower groove was larger than that obtained by a penetrator having a wider groove. (2) A penetrator having a deeper groove gave a higher value of relative strain than a penetrator having a shallower groove. (3) After the groove was perfectly filled with the testing material, the flow of the material in it could hardly be observed. (4) The stress increasing rate (df/dt) decreased with an increase of the groove cross section area, until the material was perfectly filled in the groove. (5) In the forced compression test, a higher penetration rate gave a higher stress value.

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It is commonly acknowledged that occurrence in children of certain morphological abnormities of teeth is closely associated with the presence of congenital syphilis in them. Although a great many reports are hitherto available on this problem, most of these were very divergent in either the classification or representation of the abnormities of tooth anatomy, and failed to provide any exact criterion with which one is able to make successful diagnosis. In the present study, a series of oral examination programs was undertaken on a total of 5324 pupils of primary schools, and, based on the eleven dental stigmata hitherto proposed to be involved with congenital syphilis, a group of 29 subjects bearing any one or two such stigmata was gathered out. These subjects were examined for other possible signs of congenital syphilis besides above 11 stigmata to serve for further aid of diagnosis and, based on the serology test as final evidence, diagnostic value of the above 11 stigmata was respectively evaluated. The results were summarized as follows. 1. It was concluded that Fournier's and Hutchinson's teeth proved most reliable for diagnosis of congenital syphilis. 2. Nineteen subjects had Hutchinson's teeth and 18 had Fournier's teeth and when both groups were combined, these members accounted for 29 out of the total children or 0.54% of the total. 3. Eight (31%) out of 29 subjects had both Hutchinson's and Fournier's signs combined. 4. Although no typical instance of Hutchinson's teeth was encountered in the examination of deciduous teeth, similar atypical signs of Hutchinson's stigmata were observed in both permanent and deciduous dentitions, particularly in the lower anterior and upper lateral incisor teeth of the same individuals in whom the manifestation was exceptionally strong. 5. Syphilitic eye disturbances were detected in 11 subjects (0.2%) out of the total children and these subjects accounted for about two third of 29 subjects who had either Hutchinson's or Fournier's teeth or both. 6. A lesser diagnostic value should be assigned to the dwarf teeth as compared to the above two stigmata. 7. About 10% of the teeth with constricted cusps was supposed to be involved in congenital syphilis. 8. Although occurrence of the teeth with a lava-like appearance was very few, results of the serology test administered strongly suggested that such teeth were sure evidence of congenital syphilis. 9. Those manifestations such as Kraupa's symptom (abnormal form of upper lateral incisors), the spiral teeth, mottled teeth, erosion, Carabelli's tubercle and diastema ; these proved of no value for true diagnosis of congenital syphilis.

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The pulp cavity of human being is reduced because of physiological function and pathological cause and it is made morphological changes continuously as he grows older. It is of great importance from the clinical view. To know the variation of the pulp cavity on each age is a fundamental matter to practice the root canal treatment exactly. A total of 782 human front teeth and premolar was used to examine ageing changes in the pulp cavity. Results were summarized as follows : 1. The pulp cavities of the upper incisor were reduced towards both of the mesiodistal and labio-lingual directions in each section of the teeth. The reduction was found particularly in the young age at the middle and apical sections of the root (Fig. 3∿6). 2. On the lower incisor, the pulp cavities were reduced in each section as one grew older. The stricture was found towards both of the mesio-distal and labio-lingual directions after the middle age at the coronal and cervical sections, and particularly towards the labio-lingual direction in the young age at the apical section of the root (Fig. 7∿10). 3. The pulp cavities of the upper and lower canine scarcely changed on the whole from young age to old, but the reduction was found only in the young age at the apical section (Fig. 11∿14). 4. The pulp cavities of the upper premolar were reduced as ageing and the stricture was found towards bucco-lingual direction after the middle age at the middle section of the root. On the upper first premolar, particularly the stricture was found towards the bucco-lingual direction in the young age at the cervical and upper sections of the root, and scarcely found in the old age at the apical section (Fig. 15∿18). 5. On the lower premolar, the pulp cavities were reduced towards the bucco-lingual direction in the young age at the middle and apical sections of the root (Fig. 19∿22). 6. The centers of the pulp cavities laid at the mesio-buccal region or medium of the buccal region of the teeth on the whole. Some of the teeth showed the movement of the centers in each section as ageing (Table 32∿41).

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Free skin transplantation and free mucosal transplantation were conducted clinically and histologically by many investigators. But many of these reports are about the observation of healing process generally after transplantation and the articles on the chronological changes of the nerve fibers in the mucosal grafts and the recipient beds, as far as the author has read, could hardly be found. So, the author conducted free mucosal transplantation experimentally by using the mucosal part of the lip of dog and examined its healing process patho-histologically and nerve-histologically. Results were summarized as follows ; 1. Around the 20th day after transplantation, slight contraction in the mucosal grafts was observed. After that not many changes in contraction could be observed. 2. In dogs which have melanin pigment at the recipient beds, the composure of melanin pigment into the margin of mucosal grafts could be observed around the 60th day after transplantation. 3. After transplantation, the epitheliums of mucosal grafts degenerated gradually and fell off, but a part of them survived in stripped condition. On the 5th day after transplantation, on the other hand, the epithelium of peripheral insized tissue and the epithelium surviving in stripped condition increased and began to cover the mucosal grafts, and on the 10th day it was covered completely. 4. In regenerated epithelial layer the rete pegs of each size were observed at first. Around the 20th day after transplantation, however, it became thin and flat. And from the 60th day the formation of short rete pegs was observed. 5. For one or two days after transplantation, the mucosal grafts were attached to the recipient beds with fibrin net and clot. On the 3rd day after transplantation, these junctions were observed and on the 7th day, they became complete. 6. Connective tissue under the epitheliums of mucosal grafts caused edema and alienation in the early stage after transplantation, but on the 20th day it became minute fibrous connective tissue and gradually became rough and around the 120th day it became resemble normal tissue. 7. New blood vessels of the mucosal grafts appeared on the 5th day after transplantation and they increased gradually and they became large, too. On the 30th day they became indistinguishable from that normal tissue. 8. Nerve fibers in the mucosal grafts suffered from, what is called, the Wallers degeneration and on the 7th to 10th day after transplantation they almost vanished. 9. The degenerated process of the nerve fibers differs according to their size. On the first day after transplantation, the nerve fibers of large and middle size were already degenerating, but those of small size showed the normal finding, but on second day the nerve fibers of small size also began to degenerate and after that there was little difference between the degeneration of each nerve fiber. 10. After transplantation, nerve fibers of the mucosal grafts disappeared gradually and Schwann cell increased and began to show the restis arrangement and it could be observed in all parts of the mucosal grafts. 11. On the 5th day after transplantation, observed finding of nerve fibers was seen at the cut end and the lateral of the nerve fibers at the junction of the mucosal grafts with the recipient beds. On the 10th day after transplantation, they came to enter the mucosal grafts. On the 15th day, they could be observed in every part of mucosal grafts 12. In the regenerated nerve fibers, some are closely connected with Schwann cell band and some have nothing to do with it. Most of the former were found in ones which form the bundles, and most of the latter were found in individual ones. From about 20th day after transplantation, ones that have no connection with Schwann cell band were decreasing gradually. 13. Around the 30th day after transplantation, the formation of nerve endings was observed in the regenerated nerve

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Mobidity of transfusionhepatitis is still increasing in proportion to blood transfusion volume. Therefore, studies on reduction of blood transfusion were conducted at our clinic. Operations were performed under general anesthesia supplemented with local infiltration of local anesthetics containing Epinephrine (10μg/ml). Blood trasfusion was performed in 32 cases among 579 patients. All the cases were adults. For other 547 cases, low molecular weight dextran, Lactated Ringer's solution and 5% glucose were infused instead of blood. Lactated Ringer's solution and 5% glucose were used two to three times as much as low molecular weight dextran. From the evaluation of the present cases, following summaries could be obtained. Bleeding volume (mean, per minute, per Kg) was calculated. In cleft palate cases, the mean of bleeding volume and bleeding volume per one minute was considerably low, however, bleeding volume per Kg of body weight indicated considerably high. As the result of study for blood transfusion, following criteria may be established. Indicative Criterion of Blood Transfusion in Maxillo-facial Surgery. Absolute Indication for Blood Transfusion. Bleeding volume during operation : over 1000g Bleeding volume per Kg : over 15g Bleeding volume per minute : over 8g Comparative Indication for Blood Transfusion. Bleeding volume during operation : 500-1000g Bleeding volume per Kg : 10-15g Bleeding volume per minute : 6-8g In the present study for blood transfusion, absolute indication proved to be in most cases of upper jaw resection and comparative indication in cases of resection of the lower jaw and tongue, and of neck dissection. Quantitative Criterion of Transfusion and Infusion. Volume of Infusion : 40-50% of bleeding volume at most. Volume of Infusion : Plasma Expander : About 1.5 times as volume of blood transfusion. Lactated Ringer's solution and 5% glucose : About 3 times as volume of blood transfusion. This criterion was, however, indicated for the cases under about 2000g (bleeding volume) during operation. Red blood cells, hematocrit, hemoglobin and total serum protein were examined during the postoperative period. Red blood cells, hematocrit, hemoglobin decreased to 80% of the preoperative values and recovering on the 14th postoperative day in almost all adult cases. However, in infants the recovery of these values retarded prominency compaired with adult cases. Total serum protein decreased about 0.8-1.0g/dl immediately after surgery and recovered on the 14th postoperative day in adult. But this tendency to hypoproteinemia was severer also in infants than in adults. As for 547 cases without transfusion, postoperative clinical course of these patients was uneventful and satisfactory.

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Test organisms used in the present study consisted of two strains of staphylococci isolated and identified inthis laboratory, Staphylococcus aureus 131-1 and Staphylococcus aureus 125-3, and, as reference organism, Staphylococcus aureus 209 p was collaterally used. Visual observation was made on the formation of diffuse and compact types colonies which the test organisms developed on the rabbit serum-soft agar, and special attention was directed to the investigation on the characteristics of capsular strains of those organisms that formed the diffuse type colony in the medium. Study was further eytended to the distribution of both types colonies which developed on the rabbit serum soft agar from one hundred strains of staphylococci isolated from oral infections. The clumping factor was also studied with relation to the organisms forming the compact type colony. Results obtained are summarized as follows. 1) Distribution of the compact type colonies and diffuse type colonies developing in the rabbit serum soft agar from 100 strains of staphylococci was respectively 85 with the former and 15 with the latter. 2) With use of the rabbit IgG soft agar as culture medium, occurrence of the compact type colonies amounted to 74 and that of the diffuse type colonies 26. 3) When the rabbit IgM soft agar was used as culture medium, whole 100 strains of staphylococci produced the diffuse type colonies without a single colony of compact type. 4) Occurrence of the compact type colony of staphylococcus in the serum-soft agar was presumed to have a positive correlation with some antigen-antibody reaction taking place between the rabbit IgG and protein A produced by the bacterial cell body. 5) When the 15 strains of cells which formed the diffuse type colonies in the rabbit serum-soft agar were transferred to the nutrient plate agar there to form colonies, 5 strains formed sticky colonies and 2 strains formed colonies of capsule-bearing cells, and no significant relation was noticed between both groups. 6) Animal experiments showed that the capsule-bearing strains of staphylococci were more virulent than non-capsular strains in producing the kidney abscess in mice.

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When the clasp is designed, the stability of denture in the mouth and the influence on the residual tissue have to be well considered. The load reducing clasp was first made by Evans in 1865, ever since it has been improved by Roach, Chayes and others. In the present time, many types of clasp are used fitting to the individual clinical symptom. Though there are a good many papers about the effect of clasp on the abutment tooth, almost all of them have been written about the mobility of the abutment tooth. So, the author measured the distal, the lingual or the basal stress of alveolar cavity caused by the force added to the missing portion (<7|>^^^-) of the free-end saddle denture on abutment teeth (<4|47>^^^-). The experiments were performed on the three types of clasp (Akers clasp, Roach T-bar casp and I-bar clasp), by using a commercial mandibular model. The results obtained were as follows : (1) The stress-breaking effect of Akers, Roach T-bar and I-bar clasp on the abutment tooth was different from each other. In the normal load, I-bar clasp showed the highest stress breaking effect. On the contrary, in the load of the distal direction, Roach's T-bar clasp exhibited the greatest effect as a stress breaker. (2) When the normal load was added to the right second molar portion, the distal stress was higher than the cavity base stress in case of (<4|>^^^-). (3) When the first right premolar was compressed directly, the cavity base stress was remarkably high in comparison with the distal stress.

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Numerous reports have been published on the mechanism of dentin barrier formation in the teeth of human and animal using calcium hydroxide as a dressing. However, in spite of extensive studies, these literatures contains conflicting and inadequate informations on the formative process of the dentin barrier. It was therefore proposed to attempt to clarify this problem. Vital pulp amputations were performed on the pulps of 136 root canals of dogs' teeth and the amputated pulps were covered with Calvital (a commercial form of calcium hydroxide). The teeth were histopathologically examined by hematoxylin-eosin stain, azan stain, Gomori's stain and von Kossa's silver method. Results were summarized as follows. 1. The author found that there were two patterns on the process of barrier formation. One pattern was characterized by the dentin barrier being formed immediately below the von Kossa positive granular layer (Ist type), the other by it being formed adjacent to the necrotic layer without being appeared the von Kossa positive granular layer (IInd type). 2. Both of them, the formation of the dentin barrier begins at approximately 7-10 days after pulpotomy and is performed toward the central position of the pulp from the points of the pulp chamber walls on which the dentin barrier is joined. 3. Fibrous elements, from the pulp, which take part in the formation of the dentin barrier matrix change from collagenous fibers into pre-collagenous Korff's fibers in association with the growth of its matrix. This phenomenon is accompanied with the transformation of large funnel-shaped cells into long oval-shaped odontoblasts and the formation of the homogenized matrix on the pulpal surface of the somewhat coarse matrix formed at the early stage in the development of the dentin barrier. 4. Two deep hematoxylin staining lines which are formed in association with performing pulpotomy appear in the root dentin. The deep hematoxylin staining line which exists the lateral position in the root dentin is more general feature than the hematoxylin non-staining layer, previously described by a few investigators. 5. As many investigators has stated, it is considered that the odontoblasts of the dentin barrier is derived from the connective tissue cell of the dental pulp. 6. It is thought necessary to study the necrotic layer and the part of the border between the necrotic layer and the vital pulp tissue by new methods.

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Pulpotomy was performed on the pulps of dogs' teeth using Calvital (a commercial form of calcium hydroxide) as a dressing. The teeth were subjected to histopathologic analysis for the purpose of studying the changes of nerves and blood vessels at the site of dentin barrier formation. Results were summarized as follows. 1. In most of cases of vital pulp amputations, nerve bundles and blood vessels, at the site of barrier formation, which remain at the dentin barriers are found. 2. In two patterns on the process of barrier formation, this phenomenon is more remarkable for Ist type than for IInd type. 3. Remaining neve bundles and blood vessels at the dentin barrier have a bad influence on the obliteration of the dentin barrier.

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From the fractographical point of view the relation between tensile strength and microstructure was studied for several dental plasters and stones by means of diametral compression test, scanning electron microscopy and x-ray diffraction. The following results were obtained. 1. Most of the specimens prepared from various dental plasters and stones fractured in the diametral plane containing the applied load axis. This fact shows the diametrical compression may set up a theoretical tensile stress normal to the diametral plane of the specimen. In practice, the plastic deformation of the specimen at the contact area increased with W/P ratio ; the load is distributed over the extended contact area. The fracture producing a "triplecleft" pattern was rarely observed in the present investigation of wet specimens. 2. The values of tensile strength obtained in the present investigation were nearly equal to the values in direct tension test by Nakamura et al. Consequently, it may be considered that the diametral compression test is a valid one for dental gypsum products. 3. In each specimen the longitudinal growth of dihydrate crystals increased and the tensile strength decreased as the W/P ratio increased. Therefore, the behavior of dihydrate crystals is a parameter of tensile strength in each specimen ; the decrease of tensile strength can be caused by the longitudinal growth of dihydrate crystals which brings about the decrease of contact of dihydrate crystals and the increase of the volume of porosity in the set mass. 4. Three crystal habits of hemihydrates were observed ; S type (dense stubby crystals), E type (dense elongated crystals) and A type (porous agglomerate of fine crystals). 5. Hemihydrate crystals were also observed in the fractured surface. These residual hemihydrates were dominantly observed at lower W/P ratio, although their quantity is not equivalent in each of the specimen even at the same W/P ratio according to the x-ray diffraction patterns. The set mass contained the residual E type of hemihydrates was stronger than that contained S type. 6. It is considered that the fundamental structure of set mass is composed of two phases : dihydrate and hemihydrate. Both crystals should be considered as parameters contributive to the phisical properties of set mass.

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