Except for the subjects who had suffered from general diseases causing evident disorders in the tongue according to the medical records of autopsy, seven hundred and two human tongues of autopsies, from newborn babies to 106 years old were chosen carefully from the histometrical and histopathological standpoint, and the correlation in the aging changes between fat tissues and muscle fibers was investigated. The results obtained were as follows : 1) The difference between male and female in number of fat cells was not recognized at growing period, but from twenties to thirties, it doubled from 3.7% to 6.8% on the average in the case of female. Compared with female, that of male slightly increased from 3.2% to 4.3%. 2) The number of fat cell showed the tendency of remarkable increase in female in thirties, and the number of fat cell in female was always greater than that of male in above thirties too. This tendency was recognized from growing period to the first half of old ages, and in the case of female, this tendency of increase was recognized till seventies. 3) From eighties to nineties, the percentage of fat cell was 7.6% on the average and 10.7% at one hundred years old in female, but in male it was 6.2% and 13.6% respectively. The percentage of fat cells in the tongue above one hundred years old was double that of below one hundred years old in male and the tendency of increase of fat tissue in male became greater than that of female in this generation. 4) Concerrning the percentage of fat cell in each portion, such as dorsal, marginal, septal and basal portions, it was the smallest in dorsal and septal portions, and the largest in central portion. The percentage of fat cell in central portion was two or three times as high as those in dorsal and septal portions except for the above one hundred years old. 5) The remarkable increase and enlargement of both fat cells and muscle fibers were observed in the tongue till thirties. 6) From thirties, the fat tissue always increased slightly, but the muscle fiber sectional area turned to decrease slightly. 7) From eighties, the number of fat cell showed the tendency of rapid increase, but that of muscle fiber sectional area showed the tendency of remarkable decrease. To reiterate the results written above, the number of fat cells and the sectional area of muscle fibers increased till thirties ; since then, however, the muscle fiber gradually decreased in the sectional area, and the fat cell showed the tendency of increase in number. Thus, generally speaking, in patients in advanced ages most often requiring the use of dentures, aging changes in the tongue as well as in other tissues occur, although there are some indibidual differences. Consequently, for such elderly patients, it is very important to construct the denture according to not only the mechanical techniques based on the oral anatomical index but also the physiologic ones, reflecting on the contour of the dentures the movement of the surrounding tissues of the denture, such as muscles of tongue, cheeks and lips.

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In March of 1996 the author conducted an anthropometric examination of the head and face, and measurement of the dental arch of Gurunsie tribe (39 males and 41 females), inhabitants of Paga village in the northern part of Ghana. Furthermore, the correlations between the measurements of head and face, and those of dental arches and palate height were studied. The results obtained in this study were as follows : 1) Head length : The mean value for the male is 179.9mm and for the female 172.0mm, both of the Middle Type. 2) Head breadth : The mean value for the male is 143.6mm and for the female 137.9mm, both of the Narrow Type. 3) Bizygomatic breadth : The mean value for the male is 133.2mm and for the female 129.8mm, male belong to Narrow Type and female belong to Middle Type. 4) Morphological facial height : The mean value for the male is 114.9mm and for the female 109.6mm, male belong to Low Type and female belong to Middle Type. 5) The head-type of the Gurunsie tribe, male belong to Mesocephalic Type and female belong to Brachycephalic Type. 6) The face-type of the Gurunsie tribe, male belong to Euryprosopic Type and female belong to Mesoprosopic Type. 7) Correlation : For male no significant correlation was found between bizygomatic breadth and upper dental arch breadth or between morphological facial hight and palate height. But significant positive correlation was shown in the head height and lower dental arch breadth, bizygomatic breadth and lower dental arch breadth or physiognomical facial height and palate height. In female, no significant correlation was found between bizygomatic breadth and upper dental arch breadth or between morphological facial hight and palate height. But significant positive correlation was shown in the physiognomical facial height and palate height.

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The purpose of this study was to assess the availability of the electric pulp tester (EPT) on the pulp disease. 149 teeth were tested with "Dentotest" (Swiss, Malk co. Ltd.). Specimens were investigated by histopathology. The correlation among clinical, EPT and pathologic diagnosis was evaluated utilizing the student-t test and chi-square test. The results and conclusions are as follows : 1) There is no significant difference in accordance rate between clinical (33.6%) and EPT (40.3%) diagnosis on the pulp disease, but the latter has an inclination to gain higher accordance rate. 2) As a poor correlation exists between threshold values of pulpal sensitivity to the EPT and the state of the pulp, thus pulp disease can not be diagnosed by EPT. 3) A significant difference in threshold values of pulpal sensitivity to the EPT between pathological vital (6.4±2.8) and non-vital (9.5±1.2) pulp is obtained (p<0.01). On the other hand, there is no significant difference in accordance rate between vital (85.7%) and non-vital (66.7%) pulp for clinical diagnosis, whereas a significant difference is observed for EPT diagnosis (vital : 94.3%, non-vital : 46.5%)(p<0.01). 4) There is no significant effect on the threshold values of pulpal sensitivity to the EPT in terms of sex, age, different teeth, number of roots, caries, fillings and periodontal status, whereas EPT may promote an increase of accordance rate. 5) It is observed that the fine nerve fibers accumulate and argyrophilic fibers increase at the inflammatory lesions in pulp hyperemia, acute serous pulpitis, localized acute suppurative pulpitis, chronic ulcerative pulpitis and ascending pulpitis, that is the reason why the threshold values of the EPT decreased. However, the threshold values of the EPT increase in generalized acute suppurative pulpitis, chronic closed pulpitis, acute gangrenous pulpitis and pulp necrosis (gangrene), because nerve fibers are degenerated, diminished and finally disappeared. From the mention above, we conclude that although the EPT can not diagnose the true state of the pulp, but it may play a important role in determing the vitality of a pulp. By the progress of immunohistochemistry, it is noted that the number of neuropeptide containing nerve fibers is increasing on the pulpal inflammation, but the function of neuropeptides in pulpitis is unknown, the further study is needed.

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Attention has paid to the studies on association of calcium-contained dietary treatment and bone matrix formation in recent years, considering the problem of low calcium intake in children. To maximize the peak bone mass with the help of dietary treatment is viewed as valuable for matrix formation up to 20 years of age. The present study used rats of 3- and 6-week old, which corresponding to weaning and school childhood years in human beings, to induce bone loss by calcium deficiency and low calcium feeding for 3 weeks. Calcium-balanced dietary treatment of 3 weeks followed immediately, and matrix formation of cortical bone of tibial diaphysis was investigated. The results were as follows. 1. Bone density Of 3-week-old groups, medial cortex showed decreased density in calcium deficiency and low calcium groups (p<0.05) comparing with the control group ; and interosseous cortex showed decreased density in calcium deficiency (p<0.05) comparing with the control group. Of 6-week-old groups, medial cortex showed decreased density in calcium deficiency (p<0.01) and low calcium groups (p<0.05) comparing with the control group ; and interosseous cortex showed decreased density in calcium deficiency and low calcium groups (p<0.01) comparing with the control group. Low calcium groups showed higher density than calcium deficiency groups (p<0.05). 2. X-ray microanalysis of Ca and P Higher calcium concentration was revealed than phosphorus among all the groups of 3 and 6 weeks of age, by area analysis on X-ray microanalysis. 3. Histopathologic findings Of 3-week-old groups, intercellular substance was scanty and bone marrow sparsely scattered in low calcium group, in contrast to those of control group. Of 6-week-old groups, internal and external basal lamellae showed densely thickened, and number of Haversian canals increased dramatically with the canal of comparable size. Recovery was identified significant in such bone structure as cement line and remodeling layer. 4. Hematological findings Endocrinological examination on C-PTH, N-PTH, CT, 1, 25(OH)_2VD_3 showed no significant differences among the control, calcium deficiency and low calcium groups. From the above results, dietary treatment itself could not help with recovery of bone tissue from calcium deficiency in weaning age ; while the restoration and promotion of bone matrix formation were revealed in school childhood, where bone loss from calcium insufficiency had been followed by continuing balanced dietary therapy. The action was thought to be related to the activity of hormones regulating bone metabolism.

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Recent reports show that tonsillar application is a more effective method to induce specific IgA in saliva than nasal application or intragastric instillation. In the case of the tonsillar application of Gram-positive and cariogenic streptococci, Streptococcus mutans, the antibody which intensively and selectively reacts against S. mutans is induced in saliva. The purpose of this study is to examine the efficiency of the salivary IgA induction using Gram-negative and periodontogenic rods, Porphyronomas gingivalis, as an antigen. At the sixth week after tonsillar application, anti-P. gingivalis agglutination titers and anti-P. gingivalis immunoglobulin concentrations of saliva and blood plasma greatly increased. The numbers of anti-P. gingivalis IgA-producing cells in parotid glands after tonsillar application also increased at the sixth week. Salivary IgA induced by tonsillar application reacted with allogenic strain of P. gingivalis and did not react with other bacteria including Prevotella intermedia, Fusobacterium nucleatum, and S. sanguis. The results show that tonsillar application induces salivary IgA which intensively and selectively reacts against P. gingivalis.

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We determined the prevalence of hepatitis virus carriers in a large population of hospitalized dental patients. The serum chemistries and bleeding tendencies associated with hepatitis B virus (HBV) and hepatitis C virus (HCV) also were evaluated. Twelve hundred thirty-nine consecutive hospitalized patients in a dental ward were questioned regarding a medical history of liver disease. Blood samples were taken for blood chemistry and platelet count. Serum HBs antigen and HCV antibody also were measured. Sixteen of 998 inpatients had serum HBs antigen (1.6%), while 60 of 918 were HCV seropositive (6.1%). Ninety-seven patients had a present or past history of liver disease (7.8%), and the other 1142 had no history of liver disease. The prevalence of both HBs antigen and HCV antibody was much higher in the former than in the latter. This group had increased serum levels of aspartate transaminase, alanine transaminase, and fasting plasma glucose. Blood platelet counts in hepatic disease subjects were decreased. We determined that in a large population of dental college hospital inpatients, the occurrence of HBs antigen was 1.6%, and that of HCV antibody 6.1%, which is greater than in the general population. In patients with a history of liver disease dentists should take care to avoid exposure to viruses.

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The operation involving implantation of metal into bone is increasing in clinical situation in recent years. Therefore the importance of cytotoxity test of the metals for bone cells is getting increased ; however, the effect on bone cells has not well been studied. The purpose of this study is to evaluate the effect of metal ions on osteoclast formation. Mouse bone marrow cells were cultured with prostaglandin E_2 in the presence of metal salts, including nickel sulfate, cupric chloride, titanium tetrachloride, paradium chloride, and silver sulfate. After eight days, tartarate resistant acid phosphatase-positive multinuclear cells were scored as osteoclasts. 1. Many tartarate resistant acid phosphatase-positive multinuclear cells were formed in the bone marrow cell culture with 1μM prostaglandin E_2. All of the metal salts inhibited the formation. The concentration of neckel sulfate, cupric chloride, titanium tetrachloride, paradium chloride, and silver sulfate needed for 50% inhibition of the formation is 2.5, 5, 9, 70, and 150μM, respectively. 2. In microscopic observation, tartarate resistant acid phosphatase-positive multinuclear cells and fibroblast-like stroma cells disappeared in the culture by the addition of several kinds of metal salts. In the case of titianium tetrachloride, many osteoclast-like cells appeared to be degradating, while the stroma cells did not appear to be affected. 3. In scanning electron microscopic obsevation, the number of resorption pit formed by osteoclasts was shown to be reduced by the addition of the metal ions examined. In the case of the addition of titanium salt, many pits were smaller than those of without the addition. The results show that nickel ion, cupper ion, and paradium ion inhibited osteoclast formation, probably through the nonspesific manner. Titanium ion inhibited the formation, probably through the selective degradation of newly formed osteoclasts. This specific degradation by titanium may be involved in the stable settlement of titanium implant in bone after clinical operation.

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Five-week-old male Wistar rats, corresponding to childhood in human beings, were used to investigate the effect of zinc and activated vitamin D_3 (VD_3) administration on bone formation induced by endochondral ossification. The animals were divided into such 4 groups as control, standard diet and VD_3, low zinc diet and VD_3, and high zinc diet and VD_3 groups. 1. Densitometric measurement Differences were statistically significant between control and high zinc diet and VD_3 and between control and standard diet and VD_3 groups (p<0.01). 2. X-ray microanalysis of Ca and P As compared with control group, relative ratio of Ca was higher in standard diet and VD_3 and high zinc diet and VD_3 groups, while lower in low zinc diet and VD_3. In contrast, relative ratio P was lower in standard diet and VD_3 and high zinc diet and VD_3 groups, while higher in low zinc diet and VD_3 group. 3. Histopathologic findings As compared with control group, standard diet and VD_3 group showed expanded calcified matrix enclosing hypertrophic layer, and increased number of chondroclasts resorbing calcified matrix. Increasad osteoblasts and osteoclasts with active bone formation were revealed next to subcartilaginous bone formative layer. While low zinc diet and VD_3 group showed less calcified matrix, decreased number of chondroclasts, and reduced subcartilaginous bone formation. Thin trabeculae were arranged almost perpendicularly. As compared to standard diet and VD_3 group, high zinc diet and VD_3 group showed enlarged chondrocytes evenly distributed in hypertrophic layer, with calcified matrix around. Number of chondroclasts and invasion of calcified matrix around were revealed increased, which was continued with densely arranged bone trabeculae where bone formation was identified active by increased osteoblasts and osteoclasts. 4. SEM findings As compared with control group, standard diet and VD_3 group showed expansive areas of bone resorption and formation in matrix with active new bone formation. While low zinc diet and VD_3 group showed indistinct cartilage lacunae where irregularly scattered calcified vesicles and cord-like distributed collagen fibrils were seen ; bone trabeculae were thinned and irregularly arranged. As Compared with standard and VD_3 group, high zinc diet and VD_3 group showed that lacunae were clearly demarcated by matrix formed by fused calcified vesicles, with more collagen fibrils calcified on bottom of the lacunae. Active bone formation was seen while bone formation and resorption areas mixed. From the above results, VD_3 administration facilitated in bone formation in rat's condylar cartilge, but it was shown that adequate zinc intake would promote the action of VD_3, because the present study had revealed that bone structure was damaged by insufficiency of zinc intake.

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An investigation for the dental diseases of mountain people living at trekking course of Nepal was carried out in Tukche village (2, 600m elevation) from the end of July to the beginning of August of 1995. The people of Tukche village are mostly the Thakali tribe. The purpose of this investigation is to understand more clearly the dental diseases of Nepali people, through an epidemiorogical study of this particular tribe. The results obtained under this investigation were as follows : 1. As for the DMFT of permanent teeth, the DT was 2.5&acd;3.4 for teenagers. For those in their twenties, it rose to 5.6. The MT was under 1.0 until the age of 40 years old, but it increased dramatically at ages of over 40 years. The FT could be observed very little. Except those in their forties, it was 0.1&acd;0.2 at each age. In comparison with another Nepali tribe, the DMFT was very high and its progress was fast. 2. As for periodontal disease (CPITN), many dental calculus (C) were observed ranging from young to old ages. Pockets over 6mm (P2) and missing of teeth (X) were already observed in subjects in their twenties. 3. As for the attrition, an attrition score of 1 is already observed at 13 to 15 years old. According to their advancement in age, the number and degree of attrition increased dramatically. 4. The incidence of TMJ was very low in comparison with the people of Thecho village or the Japanese. 5. As for the occlusion, malocclusion was observed in 40.0% of the villagers. Most of them was crowding (25.6%). 6. As for the brushing, 82.2% of villagers used tooth brush everyday. 7. Dental treatments in Tukche village conducted by us were mostly teeth extraction (44.9%). Scaling was 16.8% and cement filling was 14.0%. 8. Their meals consisted mostly of potatoes, vegetables, beans and milk foods. They ate little meat. They bought other items such as rice, powder milk and sugar. Their daily intake of sugar was very high (50g/day/person). We suspected that there were correlations between their dietary life and their dental diseases.

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[in Japanese]

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Six-week-old male Wistar rats, corresponding to early childhood in human, were divided into 6 groups : control group (A), standard diet・1-exercise group (B), standard diet・2-exercise group (C), calcium deficient diet・no-exercise group (D), calcium deficient diet・1-exercise group (E), calcium deficient diet・2-exercise group (F). Running exercise was scheduled as 5 days a week at a speed of 20m/min. The effects of running exercise and calcium intake were investigated on bone formation. I. Body weight Group F showed significantly lower weight than any of groups A, B, C and D (p<0.05). II. Bone density measurement with Softex radiography Standard diet group showed significantly higher density than calcium deficient diet groups (p<0.01). III. Microscopic findings Of those fed with standard diet, group B showed increased Haversian system, Haversian lamillae, interstitial lamillae and osteocytic lacnae compared with grope A. Bone remodeling was activated as demonstrated by cement lines. Grope C showed scattered marrow cavity and irregularity of osteocytic lacunae. Cement line and remordelling layer showed decreased in group C, compared with those in group A. In contrast to standard diet groups, calcium deficiency groups showed decreased width of compact bone and increased resorption. Bone marrow was seen in bone matrix and number of osteocytic lacnae decreased. Group E hardly showed any significant effect of exercise compared with group D. Group F showed less bone matrix formation and thinned cortical bone, compared with groups D and E, with bone marrow cavity and bone resorption increased within matrix. IV. SEM findings Of those fed with standard diet, group B showed expanded bone formation area and more osteocytic lacunae compared with Group A, and densely arranged collagens were seen on lacunar wall. Group C showed increased resorption area compared with groups A and B, and shallow plate-shaped resorptive lacunae were seen here and there. Calcium deficiency groups showed more expanded resorptive area than formative one, compared with standard diet group, and resorptive lacunae of irregular shape were present. No clear demarcation could be identified between bone formation and its surrounding matrix. Of those fed with calcium deficient diet, group E showed almost the same findings as group D, while group F showed expanded resorptive area compared with groups D and E, and boundary of resorptive lacuna was not clear. V. Hematological test As compared with group B and C, group D and E showed lower serum Ca level (p<0.01). Group D showed lower ratio of serum calcium and phosphorus than those fed with standard diet (p<0.01). From the above results, it showed that appropriate physical exercise facilitated in bone formation and accumulation of bone mass, while excessive exercise showed negative effect. Calcium deficiency prohibited the effectiveness of exercise.

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