Measurements were taken of the length and width of the head with use of dog skulls of Western Breed preserved in the First Department of Oral Anatomy, and the ratios of the two, or cephalic indexes were determined. Classifications based on the indexes were obtained in three types : dolichocephalic type (under 40), mesocephalic type (40-70), and brachycephalic type (over 70). For the present study, the teeth were measured of 30 cases of the mesocephalic type and 10 cases of the brachycephalic type, and a study was made of the measurements. Especially the correlation between the size of cusps and the extent of growth of the distomolars was studied. The results were as follows : 1. For all the teeth, the height, width and thickness of the mesocephalic type were greater than those of the brachycephalic type. 2. In the incisors, the mesial teeth were smallest. Closser to the distal side, the larger were the incisors. In the molars, each carnassials was largest. Further away from it, mesially or distally, smaller the teeth in order. The maxillary and mandibular first premolars and the mandibular third distomolars, in particular, were exceptionally small. 3. In the relation between the width and thickness of the crown, almost no differences were found between the maxillary and mandibular incisors and the maxillary distomolars. In the other teeth, the width was greater in comparison with the thickness. This finding was significant in the mandibular first distomolars (carnassials) in particular. 4. In determining the extent of growth of the talon in the maxillary distomolars by comparing the indexes of width and thickness with the trigone, the width was about 70% of the trigone. The percentage was greater for the brachycephalic type than for the mesocephalic type. The second distomolars were greater in index than the first distomolars. The thickness was only about 18% of the trigone. Mesocephalic type was greater in index than brachycephalic type. The first distomolars were greater in index than the second distomolars. 5. The height of hypocone against paracone of the maxillary distomolars was about 50%. 6. In the mandibular distomolars, the talonid was well grown, and its width against that of the trigonid was about 30% in the first distomolars and about 38% in the second distomolars. The latter was comparatively larger. Those of the mesocephalic type were greater than those of the brachycephalic type. 7. In the mandibular distomolars, the talonid was about 90% of the trigonid in thickness. Its thickness was larger in the first distomolars than in the second distomolars. The thickness was larger in the mesochephalic type than in the brachycephalic type. 8. The height of each cusp of the crown of the mandibular distomolars was compared with the others. Against the highest protoconid in the center, hypoconid positioned posteriorly to it, was about 56% in height in the first distomolars and about 63% in the second distomolars, whereas paraconid positioned anteriorly was about 90% in the first distomolars and about 75% in the second distomolars.

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Studies of the morphology of the mandibular premolars reveal interesting matters from the viewpoint of phylogenesis. The morphology of the mandibular premolars therefore was investigated and their morphological relation with the proximate teeth, or the mandibular canines and first molars were examined. The results were as follows : 1. In the morphology of the crown of the mandibular first molars, growth of the lingual cusp was poor. Consequently, cusps were mostly types 2+ and 2-. In occlusal sulcus type, H- was highest in occurrence. Many of the lingual cusps were positioned mesially and those positioned centrally followed. The first premolars tending to caninize in morphology accounted for 17.4%. 2. In comparison with the first premolars, growth of the lingual cusp of the mandibular seocnd premolars was good and many were types 2+ and 3-. In occlusal sulcus type, H+ was highest and type Y followed. Appearance of the distal lingual accessory cusps accounted for 38.5%. Consequently, the position of the lingual cusps further deviated mesially. 3. In the measurements of the mandibular premolars, the first premolars were longest in length and the second premolars were largest in thickness of the crown. 4. In the correlation of traits among the mandibular canines, the first and second premolars, correlation between the first and second premolars was highest, and between the canines and first premolars next. Almost no correlation was recognized between the canines and second premolars. 5. In the correlation of traits between the mandibular first premolars and second premolars and first molars, close correlation was recognized between the first and second premolars, but no correlation was recognized either between the first premolars and first molars, or between the second premolars and first molars. 6. In the bucco-lingual distance and mesio-distal distance of the crown, significant positive correlation was recognized among the canines, premolars, and molars. 7. On the basis of the foregoing, it was concluded that the first premolars possess morphological features of the canine, and that the second premolar does not possess the morphological features of the molar to the same degree.

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During this century, many sorts of recording apparatus have been developed for the study of mandibular movement. Main principle of these recorders is mechanical, photographic or electric. The electric recorder has many advantages over the photographic recorder or the mechanical recorder. For example, the electric recorder can amplify the micro portion of mandibular movement and makes possible an observation of the time-course changes in mandibular movement and also a simultaneous operation of another kind of biological signal recorder like electromyograph. The conventional electric recorders, however, must be improved further because they have a disadvantage concerning accurate recording of the physiological mandibular movement. For these reasons, the author developed a new type apparatus of the mandibular movement recorder appling the semiconductor position sensitive detector (PSD). This new recording apparatus consists of the amplification circuit and the analogue computer. The principle of this recorder is that the physiological mandibular movement is converted to the secondary dimensional output voltage and recorded. The results of the experiment with this new developed recording apparatus were as follows : 1. The output voltage of this apparatus showed the position linearity following to the movement of the target. 2. The output voltage error on the observing area (10×10cm) was limited to 2 percent. 3. The minimum distance of resolution was 0.1mm. 4. The displacement of vertical direction against the observing facet was stable within ±1.5cm. 5. The output voltage of PSD was most stable at 40mA forward current of light emitting diode (LED). On the other hand, the larger, effective aperture of lens gave higher output voltages of PSD. 6. The relationship beween the distance of LED and sensor, and the output voltage of PSD was in inverse proportion to a square of the distance between LED and sensor. 7. This new recording apparatus can be operated with electromyograph at the same time without trouble. From these results, it may be concluded that this recording apparatus is the most suitable apparatus for the further research of physiological movement of the mandible.

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The present study was conducted to investigate the pulp healing process, especially the formation of hard tissue after cavity preparation and pulp exposure without pulp capping. Two experiments were undertaken to determine : I) the correlation between the regeneration of odontoblasts immediately under the cavity and the formation of the reparative dentin after the preparation of Class V cavity in the incisors of rhesus monkeys, II) the pulp responses after allowing pulp exposure to remain without pulp capping in the rat molars. The results were as follows. Experiment I : 1. If the pulp damage and destruction in both the cell-free zone of Weil and cell-rich zone were slight, replacement with undifferentiated mesenchymal cells in the cell-rich zone led to regeneration of disappeared odontoblasts, and the reparative dentin formation similar to the primary dentin in quantity and direction of the dentinal tubules was observed under the prepared cavity. 2. If the damage in the odontoblastic layer, cell-free zone of weil, and cell-rich zone was severe, dentin matrix like predentin was formed with the cellular inclusions, and the irregular quantity and direction of the dentinal tubules immediately under the cavity. Under the matrix the arrangement of large irregular cells was observed. These cells were differentiating undifferentiated mesenchymal cells to the odontoblast. Thereafter the reparative dentin similar to the tubular dentin was formed inside the matrix. Experiment II : 1. At one or two weeks, rather extensive necrosis or gangrene developed at the exposed surface and hyalinization of the pulp tissue advanced beneath the surface with granular deposition of calcified tissue. Further below, the pulp tissue was replaced by inflammatory granulation tissue with partial hyalinization, and the hard tissue formation by the deposition of calcified tissue was observed in some instances. Simultaneously the calcified tissue was observed along the dentinal walls in the root canal. 2. Hard tissue formation was significant in the rat molars. The types were as follows. i) At the superficial layer, masses of structure-less and irregular hard tissue were observed and appeared to cover the amputated pulp surface. In addition, these hard tissues were seen within the pulp chamber. Also, the calcified tissue deposited at the dentinal walls of the root canal appeared gradually to form the thick hard tissue. ii) A hard tissue formation similar to osteoid-dentin with irregular massive lacunae in the hyaline degenerated pulp tissue was observed within the pulp chamber and along the dentinal lateral wall. iii) The hard tissue formations observed in i) and ii) were present simultaneously in the same pulp chamber. 3. In the cases where the pulp exposure was not capped and gangrene or necrosis was seen at the surface or even where the pulp tissue was replaced by inflammatory granulation tissue, total gangrene, severe inflammatory infiltration, or the occurrence of pathosis in the apical area was not observed.

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More recently, it has been suggested that the residual monomer in cured composite restorative resins may cause an tissue reaction. The purpose of this investigation was to develop a method of measuring the residual monomer eluted into water from cured materials and to investigate the toxic effect of residual monomer upon Hela cells. The toxic effects upon these cells were examined by four residual monomers (ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate and bisphenol A glycidyl methacrylate) eluted into water from cured materials. Among these dimethacrylates, bisphenol A glycidyl methacrylate produced the most unfavourable tissue reaction upon the cells.

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A case of anomaly in the region of the celiac artery and the superior mesenteric artery encountered during the dissection practice for students in 1980 are described as follows. No. 322 : age 67 male. The celiac artery, for lack of the common hepatic artery, shows the Truncus gastrolienalis (Adachi), which was divided into the left gastric artery and the lienal artery. The hepatic artery, after originating from the superior mesenteric artery, passes upward and rightward and crosses behind the portal vein (A. hepatica accessoria dextra, Adachi), then gives off the gastroduodenal artery and the right gastric artery, and enters into the liver as propria hepatic artery. This case belongs to type VI by the classifications of Adachi. Besides, the inferior pancreaticoduodenal artery was lacking in this case.

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Measurements were taken of the diameter and length of each part of commercial guttapercha points of international standard of six companies (Kerr, Zipperer, Mynol, Maillefer, G-C, and Todent). The measurements were compared with the specifications in DIN Standard to determine the status of standardization. The results were as follows : 1. The total length specified in DIN Standard is 30mm. Mynol #35, G-C #25, and Maillefer #30 were longer and the others were shorter. Rather wide variations were seen in the total length and effective length between pins of the same specification of each company. 2. In the comparison of d_1 of the six companies with that of DIN Standard, Maillefer #15 and 30, Zipperer #15, and Mynol #25 were larger, and the others were smaller. Maillefer #15 and Zipperer #15 were larger than their respective #20. Mynol #25 and 30 were about the same in diameter. In d_2, Zipperer #15 and 20 were clearly reversed in diameter. 3. Todent's approximated the tapering specification of DIN Standard. Contrarily, Maillefer's were smallest. Kerr's and G-C's had the least variations in tapering.

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One hundred specimens each of extracted central incisors, lateral incisors, and canines of the upper anterior teeth were prepared under the identical conditions. Standardized photographs with the crown axis as the standard were taken and the crown and root axes were established by the schematic outlines of the teeth. Measurements of the crown form were taken and studied. The results were as follows : 1. The averages in axial inclination of the crown and root were : 178°for the central incisors, 177°for lateral incisors, and 174°for the canines, in labial aspect ; 179°, 183°, and 175°respectively in proximal aspect. Labially, the root axis was more distally inclined than the crown axis. The inclination became greater from the median to the distal side. Proximally, the upper central incisors were not as markedly inclined as their crown axis and were nearly straight. The lateral incisors were slightly inclined lingually than their crown axis. Contrarily, the canines were labially inclined. Angles of axial inclination of the crown and root provide guides for designing and making post cores. The significant difference found between the labial and proximal axial inclination must be duly considered in designing and making post cores in crown restoration of the lateral incisors. 2. In the labial contours of the cervical line area, the central incisors were rather greater, the canines next, and the lateral incisors slightest. This finding appears to present a guide for crown restoration of the cervical 1/6 portion of the labial surface. Especially the contours of the cervical portion of the lateral incisors must be taken into consideration. 3. The ratios of the length between the contact point and incisor edge to the length of the crown were : 0.22 for the central incisors, 0.26 for the lateral incisors, and 0.37 for the canines, in mesial aspect ; 0.32, 0.38, and 0.46 respectively in distal aspect. In every case, the mesial contact point was clearly closer to the incisor edge than the distal contact point. The contact point occupies the key point in mesial and distal contours. The above reatios are considered to be guides for recreating the embrasure of the correct adjacent relationships and for reproducing the proper appearance of the teeth. 4. The ratios of the curvature of cementoenamel junction on the mesial, proximal surface to the crown length were : 0.24 for the central incisors, 0.26 for the lateral incisors, and 0.21 for the canines. The ratios on the distal, proximal surface were 0.20, 0.22, and 0.14 respectively. The mesial cervical curvature of the crown was more marked than the distal one. This finding is considered to be helpful to prosthodontic restoration of the sublingual marginal portion. 5. In comparison of the greatest curvature of the cervical line area, with the crown axis as the standard, between the labial and lingual aspects, the curvature of the lingual aspect was slightly greater than that of the labial aspect for the central incisors, lateral incisors, and canines. A significant difference of 5% level was found.

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In our clinic, dynamic impression technique is used for finished denture in order to record the physiologic mucous membrane, and relining technique is followed. The material used for relining is acrylic resin, so deformation may occur with this technique. In this report, a series of experiments was described with comparison of deformations as produced in the relining process of different procedures. The results were as follows. 1. When rectangular Acron test specimens (10×50×2mm) were relined with Acron, shrinkage of about 0.38% for relinig thickness of 2.0mm, about 0.24% for 1.0mm, and about 0.20% for 0.5mm occurred immediately after polymerizing. Convex deformation to the relinig side of 0.23×10^<-3>, 0.19×10^<-3>, and 0.15×10^<-3> also occurred respectively. 2. When Acron rectangular test specimens were relined with Repairsin, shrinkage of about 0.19% for relining thickness of 0.2mm, about 0.15% for 1.0mm, and about 0.12% for 0.5mm occurred immediately after polymerizing. Convex deformation to the base side of -0.18×10^<-3>, -0.34×10^<-3>, and -0.09×10^<-3> also occurred respectively. 3. When the relined test specimens were immersed in water at 25℃, those relined with Acron intensified the convex deformation to the relining side, whereas those relined with Repairsin reversed the curvature in two to five days. Repairsin is polymerized without heating and this causes convex deformation of the specimens to the base side (due to polymerization contraction). This deformation is considered to evert gradually along with releasing of the stress after removal of the specimens from the mould. 4. Adaptability of relining was examined with use of experimental notched specimens. In all pieces examined, resin and metal came in contact with each other on the incline and spacing on the plane occurred between them. This situation appears to reflect the conditions at the molars of the upper dentures and is suggestive of the possibility of collision of the denture with the maxillary tuberosity. 5. In both rectangular and notched specimens, the degree of deformation of self-curing resin was less than that of the materials (Acron, Quick Acron) which require heating for polymerization. In each kind of material, deformation was less in proportion to the thickness of relining. 6. The approximate water absorption volume percent was 1.52% for Acron, about 3.98% for Quick Acron, and 6.83% for Repairsin. The approximate specific volume was 0.837cm^3/g for Acron, 0.845cm^3/g for Quick Acron, and 0.849cm^3/g for Repairsin. The water absorption volume percent of Repairsin was two to four times that of the other materials. This means that Repairsin has a high risk of discoloration and deterioration because of its porosity. 7. Considering the anterior side of the denture as part of a circle, changes in curvature of the circle at Acron polymerization was examined with use of semicircular test specimens. The arc found to expand outward. This tendency further increased in the test pieces immersed in water. 8. When model mandibular dentures were polymerized with Acron, an terminal expansion of about 0.25% at the posterior end was observed immediately after polymerizing. When they were polymerized with a lateral expansion restrainer-bar attached, an expansion of about 0.08% immediately after removal of the bar occurred, and a maximum of about 0.21% in the specimens immersed in water after removal of the bar. 9. Acron mandibular dentures relined 0.5mm thick with Acron or Repairsin were compared with those relined with the same material and a bar attached. Deformation in those with a bar attached was limited to half.

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An experiment was undertaken with use of porcelain fused to metal to determine the effect of condensation and of porcelain thickness on void space (%) of porcelain immediately after condensation, on volume shrinkage at firing, and on porosity of porcelain after firing. The results were as follows : 1. With use of the condenser experimentally made for the study and under the identical condensation conditions, the void space (%) immediately after condensation varies with the volume of moulded test pieces. Consequently, condensation appropriate for the volume of moulded test pieces should be provided. 2. Volume shrinkage at firing was lower in those with less void space (%), or in proportion to adequate condensation. 3. No definite effects of condensation and porcelain thickness were found with regard to porosity which greately affects translucency of porcelain after firing. However, in those with thin porcelain, sufficient shrinking was prevented due to bonding with metal and porosity tended to increase, whereas in those with thicker porcelain, unrestricted shrinking occurred in nearly all parts and porosity tended to decrease. 4. The types of vibration which make condensation effective are considered to be those with rather high amplitude and frequency, and sharp waves (such as impulse waves). However, if frequency exceeds a certain number, moulded test pieces fail to keep pace with it and commence frequency of their own. Such frequency therefore is considered to be without effect.

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The changes in serum zinc and copper concentration were compared with the progress in hemorrhagic shock by a modified Wiggers' technique in dogs. Furthermore, zinc and copper concentrations in the liver and pancreas at the terminal point in irreversible shock were quantified. The quantity of these metals was determined by use of atomic absorption spectrophotometry (Hitachi 170-70 Zeeman Model). The results were as follows : 1. A tendency toward hypozincemia and hypocupremia was noticed in the cutaneous bleeding after acute hemorrhage (initial decrease in reversible shock). 2. In irreversible shock, remarkable hyperzincemia and hypercupremia were observed (terminal increase in irreversible shock). It can be utilized as one of the indicators procecded to irreversible shock. 3. Zinc concentration in the liver decreased significantly at the terminal point in irreversible shock.

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The malar bone is a very common site in the facial bone fractures. Many radiographic techniques are available for the detection of malar fractures, such as Waters' projection, postero-anterior projection, submento-vertical projection, occipito-mental projection, pantomography, etc. It is relatively difficult to select the correct radiographic technique for the detection of malar fractures. The purpose of this study is to compare the diagnostic accuracy of individual radiographic technique. The results obtained are as follows : 1. Waters' projection is an excellent technique for the detection of malar fractures except a zygomatic arch fracture. 2. Submento-vertical projection is excellent for the detection of a fracture of the zygomatic arch. 3. Postero-anterior projection is an inadequate technique for the detection of malar fractures. 4. Occipito-mental projection is an adequate technique for the detection of malar fractures except a fracture of the zygomaticofrontal suture region. 5. Pantomography is a poor radiographic technique for the detection of malar fractures. But it is a better radiographic technique for the detection of a posterior wall fracture of the maxillary sinus.

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Clinical evaluation of the orthopantomography is done in this study comparing it with the intraoral periapical radiography and the Waters' projection. The results obtained are as follows : 1. Lesions at the mandibular molar region are often overlooked in the intraoral periapical radiography, and lesions at the maxillary anterior region are also overlooked in the orthopantomography. Two radiographic techniques should be employed to increase detection of high incidences of pathologic conditions. 2. Orthopantomography is superior to the Waters' projection for the detection of cyst-like radiopacity but not for detection of other abnormal changes associated with maxillary sinusitis. 3. Missing teeth increase in number in proportion to aging, and more missing teeth are seen in the maxilla than in the mandible. 4. Periapical lesions increase in number in proportion to aging, and the most common periapical lesions appear radiolucent. The radiolucent lesions are predominantly seen in the mandibular molar region. 5. Widening of the periodontal membrane space increase in number in proportion to aging, and it sometimes accompanies a diffuse osteosclerosis of the surrounding bone. 6. Most of the lesions located apart from the root apex appeared as radiopaque, and radiopaque lesions are predominantly seen in the mandible.

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