X-ray microprobe analysis (XMA) is the best method at present to analyze the quantitative concentration of calcium (Ca) or phosphorous (P) in hard tissues. However, the analytic area on intertubular dentin was not larger than the X-ray source region of Ca or P under the usual conditions of the XMA system. In this study, we considered reduction of the X-ray source region. XMA was conducted using a S-2500 CX scanning electron microscope (SEM : Hitachi, Tokyo, Japan) fitted with a Quantum delta IV energy-dispersive X-ray analytical system (EDX : Kevex, San Carlos, USA). We observed changes in X-ray source region with accelerated voltages (ACC. voltage) of SEM, and changes in analytic contents in a sample surface at various tilt angles. Consequently, the analytic area was able to be decreased on a sample surface at a tilt angle of 27.5° under a lower ACC. voltage of SEM. Actually, we analyzed Ca and P in the incisor rat dentin surface at the tilt angle 27.5°. Analytic portions were intertubular or peritubular dentin on the labial side in an incisor dentin. In this case, the SEM was operated at 7, 10 and 15 kV ACC. voltage with a 0.1 nA probe current. Then, XMAs were conducted for quantitative Ca and P in the intertubular and peritubular dentin on the lingual, proximal, distal, and labial sides in the incisor dentin. Though an ACC. voltage of 7 kV was able to obtain the most exact concentration in the results for intertubular or peritubular dentin, there was no significant difference against measurement values with 10 kV. The Ca content in the peritubular dentin on the labial side was higher than the measured value of peritubular dentin on the lingual side.

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Fibrous and cellular components of the lamina propriae in rat circumvallate papillae were examined ultrastructurally. Six-month-old Sprague-Dawley strain rats were perfusion-fixed with glutaraldehyde solution and processed for electron microscopic observations. The lamina propriae were composed of irregularly-arranged dense connective tissues consisting mainly of bundles of type-I collagen fibers. Among these collagen bundles, elastic fibers consisting of elastin deposition over aggregated microfibrils were randomly distributed. As cellular components, fibroblasts exhibited an inactive fibrocyte-like structure with a less-developed Golgi-RER system. Smooth muscle cells were present randomly in close association with surrounding microfibrils and elastic fibers. Many eosinophils, plasma cells, and mast cells were also distributed, but neutrophils and macrophages were seldomly observed. In postcapillary venules and capillaries, endothelial cells protruded towards the capillary lumen and became the sites of white blood cell invation into the tissue proper of lamina propriae. From our observations, it is evident that the lamina propriae of circumvallate papillae are composed of dense fibrous connective tissues including three kinds of fibrous elements and contain many immuno-responsive cells forming the mucosa limmune system and sensory free nerve endings associated with the neuroepithelial cells in taste buds.

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Collagen fibrils and elastic fibers contained in the normal retrodiscal tissue of the temporomandibular joint (TMJ) were studied with emphasis on the visualization of their three-dimensional organization using a scanning electron microscope. The retrodiscal tissues were taken from human adult cadavers ranging from 56 to 78 years old.
The main fibril bundles seen in the posterior band of TMJ disks presented a linear or wavy appearance and ran anteroposteriorly in the vicinity of the retrodiscal tissue. These bundles became less compact at the posterior band-retrodiscal tissue junction and the anterior border of the retrodiscal tissue. There was a stack of lamella composed of fibril bundles that predominantly ran anteroposteriorly in the uppermost layer of the retrodiscal tissue. The fibril lamellas passing mediolaterally, and a network of elastic fibers, were seen in the layer below the uppermost surface. In an intermediate layer of retrodiscal tissue, linear, lamellar, wavy or spiral bundles of fibrils were irregularly and sparsely arranged. The deepest layer contained a stack of lamella composed of anteroposteriorly, mediolaterally, or irregularly arranged fibril bundles. The organization of the fibril bundles and elastic fibers seems to provide some elasticity under tensile stress. The retrodiscal tissue is similar to the TMJ disk in this regard, but may exert little resistance to functional pressure because of the spase arrangement of fibrils.

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It is well known that occlusal interferences induce some systemic symptoms in clinical research. However, the mechanisms of abnormality of circulatory hemodynamics (CH) induced by occlusal interference still remain unclear. The present study was conducted to clarify the influences of bilateral bite raising for CH. Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR) and activity (Act) were measured with an implanted telemetry system in conscious and unrestrained spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Bilateral bite raising splints were set on the upper dentition. The primary value of Act and HR in WKY and SHR decreased remarkably; however, SBP and DBP tended to increase in WKY and SHR. After that, the SBP and DBP of WKY decreased gradually and those of SHR were kept at higher levels. The coefficient of variation for SBP and DBP increased by stress from bilateral bite raising. These results suggest that activation and instability of the sympathetic nervous system are induced by stress from bilateral bite raising, which brings about changes in CH.

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The area around the orbit, nasal cavity and paranasal sinuses of the skull forms an ideal reinforced structure. Three vertical pillars, that is, the canine, zygomatic and pterygoid pillars, exist in the skull. The canine and zygomatic pillars connect horizontally at the supraorbital and infraorbital borders. On the other hand, the vertical pterygoid pillar and the zygomatic arch connect horizontally at the articular tubercle. It seems that the areas connecting each pillar horizontally are the transfer routes for dispersing and relieving masticatory pressure. In this study, we observed the bone lamellae of compact bone and fibrous matrix with a high-resolution scanning electron microscope, and discussed the relationship between the stress to masticatory pressure and the fibrous matrix. Compact bone of the supraorbital and infraorbital borders, which seemed to disperse and relieve the masticatory pressure, was formed by external and internal basic lamellae composed of about ten layers of bone lamellae and the Haversian lamellae composed of curved osteons. Compact bone of the horizontal articular tubercle was formed by the external basic lamellae arranging in the external-internal direction and the Haversian lamellae composed of curved osteons. The bone marrow space exsited in compact bone of the articular tubercle, and we thought that the bone marrow cavity was the dispersing route of the masticatory pressure transferred from the zygomatic arch and pterygoid process, and neutralized the masticatory pressure. The main matrix fibril bundles in the bone lamellae of the basic and Haversian lamellae of three horizontal areas transfer the masticatory pressure, and the matrix fibril bundles crossing the main matrix fibril bundles added elasticity to the compact bone.

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Somatometric measurements were taken on the craniofacial area of Filipino belonging to Sundadonty and of Japanese and Chinese belonging to Sinodonty. Migration of two mongoloid lineages of Sundadonty and Sinodonty were deeply related to the origin of the modern Japanese. The measurements were stature, head length, head breadth, head height, bizygomatic breadth, bigonial breadth, and morphologic facial height according to the method by Martin Seller, and the morphological facial depth by Minobe et al. Craniofacial indices (the cephalic index, cephalic length-height index, cephalic breadth-height index, morphologic face index, zigomatic gonial index and morphologic face depth index were calculated from the measurements.These measurements and indices were compared in relation to the three populations statistically.
The results were follows : With the exception of head length and morphologic facial depth, the mean values of the measurements were largest in Chinese, followed by Japanese and the smallest in Filipino. Japanese had significantly large head length and morphologic facial depth than the other population (P<0.01). The results of this study supported Hanihara's double structure model on the origin of Japanese.

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A rare case of a dentigerous cyst associated with a tooth-like structure in a 34-year-old male is reported. Radiologically, a well-defined radiolucency around the crown of an impacted right lower third molar was seen. Histopathologically, the radiolucent lesion was diagnosed as dentigerous cyst with tooth-like structure and small foci of mineralization in the cyst wall.

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