Of the panoramic radiographs kept in the Department of Dental Radiology at Kyushu Dental College Hospital, 210 panoramic radiographs of edentulous jaws were investigated. Items for investigation were the distance from the floor of the nasal cavity to the floor of the maxillary sinus, the distance from the floor of the maxillary sinus to the maxillary alveolar crest, the distance from the mandibular alveolar crest to the mandibular canal, and visual evidence of a mandibular canal. The measurements obtained in this study include a magnification factor. The results obtained by this study were summarized as follows : 1. The distance from the floor of the nasal cavity to the deepest point of the sinus floor on the right side was 9.4±4.62mm and was 9.4±5.05mm on the left side. The distance from the floor of the nasal cavity, beneath the infraorbital canal, to the sinus floor was 8.1±5.11mm on the right side and was 7.1±6.30mm on the left side. There was no statistical difference between the right and left sides in the distance from the floor of the nasal cavity to the floor of the maxillary sinus. 2. The distance from the deepest point of the sinus floor to the alveolar crest on the right side was 6.9±4.75mm and was 6.6±4.78mm on the left side. The distance from the floor of the maxillary sinus, beneath the infraorbital canal, to the alveolar crest was 8.0±5.03mm on the right side and was 8.7±5.79mm on the left side. There was no statistical difference between the right and left sides in the distance from the floor of the maxillary sinus to the alveolar crest. 3. Of the 210 cases, 77 (37%) revealed clear images of the superior wall of the right mandibular canal between the mandibular and mental foramina. On the left superior wall of the mandibular canal, 76 cases (36%) showed clear images. Of the 210 cases, 131 (62%) revealed clear images of the inferior wall of the right mandibular canal between the mandibular and mental foramina. On the left inferior wall of the mandibular canal, 123 cases (59%) showed clear images. There was a statistical differrence between the superior and inferior walls of the mandibular canal on the clear visualization of the image. However, there was no statistical difference between the right and left sides of the superior and inferior walls of the mandibular canal visually. 4. The distance from the alveolar crest of the mandibular molar region to the superior wall of the mandibular canal was 9.1±5.54mm on the right side and was 9.9±5.05mm on the left side. There was no statistical difference between the right and left sides on the distance from the alveolar crest of the mandibular molar region to the superior wall of the mandibular canal. From the above results it was known that there was no difference between the right and left sides on the distances from the floor of the nasal cavity to the floor of the maxillary sinus, from the floor of the maxillary sinus to the alveolar crest, and from the alveolar crest of the mandibular molar region to the superior wall of the mandibular canal in the edentulous jaws. It is also clear that the clear visualization of the superior wall of the mandibular canal between the mandibular and mental formina was less clear than that of the inferior wall.

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Importance of calcium intake in diet during the childhood from the infantile period through preschool age, school age, and puberty in the growth stage has been pointed out in recent years. Three-week-old male rats of Wistar strain were used and changes caused by supplying calcium in the debilitated mandible in the growth stage and also changes in the mandible given high calcium for an extended period were investigated morphologically, and for bone density and compressive strength. The results were as follows : 1. Morphological measurement 1) Coordinate analysis High calcium diet group and calcium-deficient diet + standard diet group, as compared with control group, both showed significant differences (p<0.05) in many measurement items. Decrease in the degree of growth in the mandibular morphology was observed. Calcium-deficient diet + standard diet group, as compared with high calcium diet group, showed further decrease in the degree of growth. 2) Actual length measurement A. Length measurement Control group showed high values followed by high calcium diet group and calcium-deficient diet + standard diet group. As compared with control group, high calcium diet group with a 5% significance level (excluding AI-Id') and calcium-deficient diet + standard diet group with a 1% significance level showed low values. As compared with high calcium diet group, calcium-deficient diet + standard diet group showed low values (excluding Id'-M3) with a 5% significance level. B. Height measurement Control group showed high values followed by high calcium diet group and calcium-deficient diet + standard diet group. As compared with control group, high calcium diet group and calcium-deficient diet + standard diet group with a significantly low values (p<0.01). As compared with high calcium diet group, calcium-deficient diet + standard diet group, Cd-Ag alone, showed significantly low values (p<0.05). 3) Angle measurement The measurement points of each group showed nearly same values. Only the coronoid process angle, control group showed significantly lower values with a 5% significance level as compared with high calcium diet group. 2. Bone density No significant differences were seen between control group and high calcium diet group. Calcium-deficient diet + standard diet group, as compared with control group and high calcium diet group, showed significantly low values (p<0.05). 3. Compressive strength Control group showed no significant differences as compared with high calcium diet group. Calcium-deficient diet + standard diet group showed significantly low values (p<0.05) as compared with control group and high calcium diet group. On the basis of the foregoing findings, for the mandible in the growth stage, administration of high calcium for an extended period does not necessarily result in favorable effect. Nor sufficient recovery can be expected for the debilitated mandible in low-age children even with administration of standard diet.

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It has been made clear that amounts of intake of calcium and protein greatly affect internal structure of the jaw at the growth stage. However, there are differences in the views made in the reports on bone construction related to the amount of calcium intake and the level of protein intake. Therefore, and investigation was made on the effect of hyperprotein meal on the mandible. The results were as follows : I. Roentogenographic and bone density findings In the control group, the alveolar bone showed even thickness at the surface of incisors, and trabeculae were densely arranged. In the hyperprotein meal group as compared with the control group, decrease in traveculae and reduction in thickness of the whole alveolar bone were seen. In bone density findings, no significant differences were found between the two. II. Analytical findings of Ca and P on the X-ray microanalyzer In characteristic roentogenograms, Ca showed higher concentration than P within the same trabecula. Furthermore, hardly any difference was found between the relative specific of calcium quantity and relative specific of protein quantity of the control and hyperprotein meal groups. III. Hematologic findings No changes at all were found in electorolyte in serum and in biochemistry examination. IV. Histopathological findings In the hyperprotein meal group as compared with the control group, woven bone and spongy bone decreased extensively and bone marrow expanded markedly. In the median alveolar bone and buccal alveolar bone, the periodontal membrane showed extensively irregular arrangements. V. Scanning electron microscope findings In the hyperprotein meal group as compared with the control group, many amorphous bone lacunae were seen, and the borders with the surrounding matrices were unclear, and collagen fibrils were distributed sparsely. On the basis of the foregoing findings, it is suggested that the formation of bone matrix decreases by maintaining intake of hyperprotein meal for an extended time for the mandible at the growth stage.

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The purpose of this study is to investigate the osteoclast inducing activity in the bone extract from long bone of normal rats and from alveolar bone of untreated and orthodontic appliance installed rats. Bone extract was added to mouse bone marrow culture, and the induced osteoclasts were monitored by counting the number of tartrate-resistant acid phosphatase (TRAP) positive cells and mesuring the area of the pit formed. 1. In long bone extract from the normal rats, the osteoclast inducing activity was recognized. The increase was suppressed by hydroxyurea, an inhibitor of cell proliferation. 2. In alveolar bone extract from the untreated rats, the osteoclast inducing activity was also recognized. The increase in the activity by adding 10^<-6>M PGE_2 was low in alveolar bone extract and high in the long bone extract. 3. When 10 g orthodontic forces was applied at upper incisors for 3 days, the osteoclast inducing activity in the alveolar bone around the incisors increased more than that in untreated bone. The activity of the bone applied the force for 6 or 10 days decreased and became less than that of untreated bone. When 10^<-6>M PGE_2 was added to the culture in order to cancel the influence of the inducing activity of PGE_2 preexisted expected to be contained in the extract, the activity appeared to be the same as that without adding PGE_2. 4. When 100 g orthodontic forces was applied at upper incisors for 3 days, the osteoclast inducing activity in the alveolar bone around the incisors was less than that of untreated bone. The activity of the bone applied the force for 6 or 10 days was less than that of the untreated bone. The activity was not affected by the addition of 10^<-6>M PGE_2. The level of the activity was lower than that of PGE_2 alone. Since the osteoclast inducing activity in the alveolar bone changed in response to the external loading force, this activity may be involved in the bone-remodeling process during orthodontic tooth movement. Excess amount of PGE_2 little affected on the change in the osteoclast activity of the alveolar bone extract during the tooth movement. PGE_2 seemed not to be predominantly related to the activity.

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Titanium has many favorable characteristics for dental use such as low specific gravity, high strength, and excellent corrosion resistance and biocompatibility. The present study examined the effective application of titanium to ceramo-metal restoration in terms of surface aspects and bond strength with porcelain. The titanium surface was subjected to mechanical abrasion and/or oxidization heat treatment before fusing a commercial porcelain for the exclusive use with titanium. Tensile tests were carried out for butt-fused sandwich specimens. When the titanium surface was polished with #600 emery paper, the bond strength with porcelain was as low as 0.4MPa. Sandblasting treatments of the surface could significantly improve the bond, in which the alumina sandblasting showed the highest strength of 35MPa exceeding those obtained between the conventional alloys and porcelain. In addition to the physical bonding induced by the increased surface roughness, the remaining alumina particles in the titanium surface layer were proved to act as an intermediary for chemical bond between titanium and porcelain. Auger microanalysis revealed that an oxide film 50 to 60Å thick existed on the titanium surface after polishing. The oxide thickness slightly increased to at most 300Å by oxidization heat treatments up to 600℃, resulting in no significant improvement in bond strength with porcelain. The treatment at 800℃ caused a rapid growth of TiO_2 layer 7 to 8μm in thickness and the specimen showed a significant increase in bond strength. The fractography demonstrated that the porcelain tightly fused to TiO_2 and the fracture occurred in a mode of cohesive failure within the oxide layer. By heating at 900℃, the bond strength significantly decreased while the oxide thickness further increased. It indicates that the formation of TiO_2 may be effective for bonding with porcelain but the presence of too thick oxide will cause easy cohesive failure because of its coarse and brittle structure. Although the oxidization at 800℃ was effective in the polished titanium specimen, no more additional effects of oxidization could be found in the alumina sandblasted specimen. The foregoing results suggest that in the titanium coping only the alumina sandblasting treatment prior to porcelain fusing may be enough for obtaining practically satisfactory bond strength.

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Tumor invasive and proliferative potential might be one important prognostic factor, and to elucidate correlation with these factors in oral squamous cell carcinoma (O-SCC) might be important. Recently, various monoclonal antibodies have been developed and used in immunohistochemical studies of malignant tumors. When we study the tumor invasive and proliferative potential, not only tumor cell population but also the tumor-host relationship could be important. Therefore, the purpose of this study was to investigate the invasive and proliferative potential of O-SCC. The development of p53 protein and bcl-2 protein, and the distribution of Type IV collagen were immunohistochemically studied in 50 patients with O-SCC. The results were as follows : 1. Development of p53 protein was detected in 54% of O-SCC. This was localized in the nucleus of tumor cells. 2. No statistical correlation was observed between the development of p53 protein and clinico-pathological parameters, including T classification, histological differentiation, mode of invasion, and pathological lymph node metastasis. p53 protein was frequently expressed in T1. No statistical correlation was observed between development of p53 protein and a 5 year survival rate. 3. Development of bcl-2 protein was detected in 12% of O-SCC. bcl-2 protein was mainly localized in the cytoplasm of the tumor cells, particularly around the nucleus. 4. No correlation was observed between the development of bcl-2 protein and clinicopathological parameters, or in the development of p53 protein. 5. The distribution pattern of basement membrane surrounding cancer nests in O-SCC varied as follows : continuous group-42%, discontinuous group-42%, absent group-16%. 6. Changes of basement membrane in O-SCC had a significant correlation with T classification, mode of invasion and pathological lymph node metastasis, but not with histological differentiation, inflammatory infiltration, or a 5 year survival rate. These results suggest that in the process of invasion and proliferation of O-SCC, p53 abnormalities may be associated with early invasion in O-SCC, and maintained during the process of proliferation. Also, the distribution pattern of basement membrane around cancer nests of O-SCC significantly correlated with invasive, proliferative and metastatic potential. This may be one useful parameter to elucidate biological behavior. The significance of development of bcl-2 protein in O-SCC, however, was not clear and may differ with the type of organs.

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In order to evaluate the validity of titanium and its alloys for denture framework, the present study examined the potential bonding of a pour-type denture base acrylic resin to Ti-6 Al-4 V alloy under application of a metal primer. The primers employed were three commercial products containing different adhesion promoting monomers : Metalprimer (MEPS abbreviated to MP), Metabase M (4-META, MB) and Opaqueprimer (phosphoric methacrylate, OP). The surface of the cast alloy rod was subjected to mechanical abrasion or oxidization treatment and a primer was applied onto it before pouring the resin to form a butt-jointed resin-alloy specimen for tensile test. The acrylic resin showed no measurable bond strength to the polished alloy without priming treatment. The application of the primers could induce chemical bonding between them, in which OP was the most effective showing as high bond strength as 108kgf/<cm>^2 significantly larger than that for Co-Cr alloy and MP the least. When the alloy surface was sandblasted before priming, the bond strength significantly increased by a combined effects of the physical and chemical reactions in MP and MB (p<0.01). In OP, on the other hand, the maximum bond strength was already attained by its chemical bonding to the polished alloy and no more additional effects of sandblasting appeared since the failure occurred in a mode of cohesive fracture within the weakest primer layer. In general, it has been demonstrated that the bond of adhesives to metal is attributed to the presence of some oxide film on the metal. Auger electron spectroscopy revealed that an oxide film 50 to 60Å thick was formed on the polished titanium alloy surface. The oxide was thickened to 100, 160 and 350Å by oxidization heat treatments at 100, 200 and 500℃, respectively. As the oxide thickness increased, the resin-alloy bond strength significantly decreased (p<0.01). Although it was then attempted to remove the oxide film by fluoride treatment, new oxide about 50Å in thickness was formed immediately after the treatment resulting in no improvement in the bond strength. Even when the alloy was aged in a desiccator, the oxide gradually grew and the bond strength significantly decreased in three days. Thus, unlike the conventional alloys, the titanium alloy showed better bonding with acrylic resin under the existence of thinner oxide film in angstroms, and it is recommended in practice to abrade or polish the alloy framework immediately before applying the primer.

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No unified view has yet been reached on the relation between calcium absorption and protein intake both of which play important roles in the formation of bone matrix at growth stage. Five-week-old male Wistar rats therefore were used and high protein diet and calcium utility in enchondral ossification in the mandibular condyle were investigated electron microscopically. The results were as follows : I. Scanning electron microscope findings In high protein diet group, as compared with control group, the borders of chondrocyte lacunae were indistinct and calcospherites in chondrocyte lacunae below hypertrophic zone showed few fused ones. Sparse collagen fibrills were observed in the space between spherites. Trabeculae were thin and running irregularly. In calcium deficient diet group, as compared with control and high protein diet groups, calcospherites in the chondrocyte lacunae below hypertrophic zone were decreased and wide spaces between spherites were found. Trabeculae were thin and bone resorption was increased. In calcium deficient diet + high protein diet group, as compared with calcium deficient diet group, calcospherites in the chondrocyte lacunae were decreased. Trabeculae were thin and bone resorption was marked. II. Transmission electron microscope findings. In high protein diet group, as compared with control group, increase in flattened and resting osteoblasts was marked. The percentage of osteoid osteocytes in osteocytes was increased. Osteoclasts varied from large to small ones and their number also increased. In calcium deficient diet group, as compared with high protein diet group, extensive decrease in osteoblasts was seen and flattened ones increased. Preosteoblast-like cells with egg-shaped nucleus few in peripheral chromatin were increased. Osteocytes showed similar findings as in high protein diet group. Osteoclasts were varied in morphology from large to small to ones, and their number was increased as compared with high protein diet group. In calcium deficient diet + high protein diet group, as compared with calcium deficient diet group, flattened osteoblasts few in organelles and preosteoblast-like cells showed a tendency to increase. Osteocytes showed similar findings as in calcium deficient diet group. Increase in osteoclasts was marked and bone resorption was active at the developed ruffled border. On the basis of the foregoing findings, it was suggested that excessive protein intake gives negative effect on the formation of bone matrix by enchondral ossification in the mandibular condyle of the rat at growth stage.

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Prevotella intermedia is frequently detected in the microflora of patients with several types of periodontitis, and thought to be one of the most important etiological agents. P. intermedia was found to have high Alkaline phosphatase (ALPase) activity. ALPases are previously known to be one of the virulence factors to periodontal organisms. However, many enzymological properties of ALPase are unknown. In this study ALPase of Prevotella intermedia ATCC25611 was solubilized by extraction with 1% Triton X-114, and the solubilized enzyme was purified 47.4-fold with 3.3% recovery by using ion-exchange chromatography, gel-filtration and affinity column chromatography. The purified enzyme was observed as a single protein band that corresponded to molecular weight of 54, 000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis preparations. The molecular weight of the native enzyme was estimated to be about 150, 000 by gel filtration with TSK-gel G3000SW_<XL>. These findings indicated which P. intermedia ALPase is a dimer or a trimer. The purified enzyme dephosphorylated phosphotyrosine-containing human gastrine, a peptide substrate for protein tyrosine phosphatases (PTPases), and was inhibited by sodium orthovanadate, sodium molybdate and Zn^<2+>, which are inhibitors of PTPases activity. The purified enzyme was indicated that the optimal pH for ALPase activity was about 9.5 and the optimal pH for PTPase activity was about 6.0. The PTPase activity was reduced by approximately 10% of maximum at pH7.0. This result suggests that the purified enzyme can have about 90% of the maximum activity even under physiologically relevant conditions. The N-terminal sequence of the purified enzyme showed about 50% homology with the sequence of amino acids sharing an active site signature motif, (I/V) HCXAGXGR (S/T)G, which all of PTPases conserve. Therefore P. intermedia ALPase was found to have protein tyrosine phosphataselike activity and characterization.

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Dentofacial deformities result from abnormal growth of facial bones. The purpose of orthognatic surgery is to improve functions and esthetics. If the improvement in esthetics is not sufficient, the patient may not be satisfied with the results of treatment. This study was prompted by the realization of a need for more substantial data from which a reliable, predictive format could be developed to aid in treatment planning for prognathic patients. Forty patients treated surgically for mandibular prognathism were selected from the files of the First Department of Oral Surgery, Kyushu Dental College Hospital. In all of the cases selected, surgery had involved sagittal split ramus osteotomy and orthodontic treatment had been performed pre- and postoperatively. Four sets of lateral radiographic cephalometric films were taken for reference : Just before surgery, 1 month, 3 months and 6 months after surgery. The effect of treatment was posterior movement of soft and hard tissues of the lower third of the face. Further, a trend toward relapse consisting mainly of anterior displacement persisted until 6 months after surgery. Prediction of the postoperative position of soft tissues was evaluated by stepwise multiple regression analysis. Then, a multiple regression equation which showed a coefficient of determination over 0.9 with as few variables as possible and with significance below 0.01 on F-test was determined as a predicting equation. Furthermore, residual standard deviation of all multiple regression equations were less than 2.0 mm. Nevertheless, cases with open bite and high or low tension of the lower lip showed major predictive error. Prediction of the postoperative soft tissue profile following orthognathic surgery is possible with sufficient precision for clinical use using these multiple regression equations.

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The appearance and the localization of cytokines, including interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), epidermal growth factor (EGF) and transforming growth factor-β (TGF-β), was studied in healing tissue after tooth extraction. The marker enzymes, alkaline phosphatase (ALP) for osteoblasts and tartrate resistant acid phosphatase (TRAP) for osteoclasts, were examined as well. The results obtained are follows : 1. IL-1β-positive sites were markedly observed in blood clot in extracted tooth socket and on the alveolar bone surface of the socket wall on Day 1, and subsided gradually on Days 3, 7 and 14. 2. TNF-α was also markedly observed in blood clot in extracted tooth socket and on the alveolar bone surface of socket wall on Day 1, and the positive reaction gradually subsided thereafter. 3. EGF-positive reaction was markedly observed in granulation tissue in extracted tooth socket and alveolar bone surface on Day 3. The positive reaction gradually subsided on Days 7 and 14. 4. TGF-β-positive reaction was noted in blood clot in extracted tooth socket from Day 1, and it gradually subsided on Days 3 and 7. On Day 14, TGF-β was markedly observed again around new bone trabeculae. These results showed that the cytokines in the healing process of extraction wound appeared in a similar way of that in the healing process of inflammation model. The cytokines were asumed to be involved in some healing process through each or combined effect. The amount of the produced cytokines might affect the healing efficiency in clinical tooth extraction.

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In 1994/95, a follow-up survey of a 1988/89 survey about the oral health conditions and treatment needs of dental disease was carried out for institutionalized elderly people. Base line survey comprised 1, 959 persons aged &ge;59 years in 29 institutions in Kitakyushu, Japan. The purpose of this study is to observe changes in tooth and denture conditions with advancing age and to clarify tooth and denture conditions contributing to general health. Dentition, wearing of and need for dentures were assessed according to WHO guidelines (Oral health Survey-Basic Method, 3rd Ed., 1987). Interviews were also conducted and data on general health status were obtained from the subjects' medical histories. Seven hundred and nineteen people were re-examined for the baseline survey. One thousand two hundred and forty persons were dropped from the present survey because of death (878), of hospitalization (191), they left the institution (147), and they refused and oral examination (24). Percentage of edentulous persons increased 8.5% from 47.7% at baseline to 56.2% in 1994/95. In dentate persons, mean number of teeth, mean number of DF(decayed and filled) teeth, D(decayed) teeth and F(filled) teeth was 10.6, 6.6, 0.8, and 5.8 in 1988/89, and 9.1, 7.0, 1.7, and 5.4 in 1994/95, respectively. Percentage of persons needing denture treatment increased 10% from 74% at baseline to 84% in 1994/95 and the worse general health status was, the more denture needs increased. Denture conditions of persons who received denture treatment at least once during the 6 years improved. General health status including, physical and mental health, of institutionalized elderly people got worse with increasing age. In multivariate analyses general health status became worse with decreasing number of teeth and with worsening denture conditions when the effects of other factors were controlled. Especially, physical health conditions in edentulous, no denture wearing, subjects became about 10 times more serious than that of persons with &ge;20 teeth. During the same period, the mental health conditions of subjects became 3 times worse. In dentate persons, persons with severe carious teeth had a 1.7 times higher risk to physical health than persons without severe carious teeth. Mortality increased with worsening physical and mental health. The risk of mortality of persons with no denture wearing increased with decreasing number of teeth, but mortality of persons with denture wearing did not increased even if the dentures needed repair or remaking. The results suggest that healthier oral health conditions might contribute to maintaining better health in older age cohort. So, keeping more teeth is the most important for keeping good general health status of institutionalized elderly people, and if elderly people loose some teeth, it's necessary to wear good dentures. But, institutionalized elderly revealed poor dental health conditions and high treatment needs of their mouth. The results emphasize the necessity of improving the dental health system for the institutionalized sector of the population and also the importance of preventive programs for dental diseases and dental health education in the younger generations.

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In 1994/95, a follow up survey of a 1988/89 survey was carried out for institutionalized elderly people. Baseline survey comprised 1, 959 persons aged &ge;59 years in 29 institutions in Kitakyushu, Japan. 719 were re-examined for the 1994/95 survey. 1, 240 persons were dropped from the present survey because of death (878), hospitalization (191), release from the institution (147) and refusal of an oral examination (24). The purpose of this study is to provide cross sectional results of the present survey, to observe changing patterns of periodontal conditions with advancing age and to clarify periodontal conditions contributing to general health. In the 1994/95 survey, all dentate subjects were assessed bleeding on probing and calculus deposits, and pocket probing depth and attachment level by 1 mm at 6 sites of all remaining teeth. The data were recalculated to adjust to the CPITN presentation. Percentage of dentate persons decreased 6.1% from 49.9% at baseline to 43.8% in 1994/95. In dentate persons, the mean attachment loss was 4.1 mm, and the mean pocket depth was 2.8 mm. Almost all the subjects had at least 1 site of attachment loss of 4 mm, and 64% had at least 1 site of attachment loss of 7 mm. 88% of subjects had at least 1 site of pocket depth 4 mm, and 27% had at least 1 site of pocket depth 6mm. In the changing periodontal conditions for institutionalized elderly people, measured by CPITN percentage of persons and mean number of sextants from 1988/89 to 1994/95, percentage of persons and mean number of sextants with moderate and deep pocketing increased, in addition to increasing the numbers of excluded sextants. To identify risk indicators and risk markers for periodontal disease experience, using cross sectional survey data, multivariate analyses were used to examine the relationship between age, general health, and the number of remaining teeth and severe periodontal disease. Severe periodontal disease was arbitrarily defined as >30% of all measured sites per person with attachment loss exceeding the mean attachment loss and >30% of all measured sites per person with pocket depth exceeding the mean pocket depth. In result, the most consistent predictor of periodontal disease experience were current general health conditions. In addition, the objective of the follow-up study was to analyze data about the relationship between periodontal conditions and general health in older age cohort. Multivariate analyses indicated that persons with periodontal pockets with &ge;4 mm had a risk 2.0 times higher than persons with pockets &le;3mm of worsening their physical and/or mental health. These results suggest that sites with severe attachment loss are typically not accompanied by severe pockets and periodontal disease experience is influenced by current general health in cross sectional survey and healthier periodontal conditions might contribute to maintain better general health in older age cohort.

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This study investigated tooth position influenced by periodontitis. Litter of four mongrel dogs served as subjects. A metal cap was set on both sides of the lower 3 rd premolar, and a bridgetype splint used for measuring the amount of tooth migration was splinted on both sides of the lower canine and 1st molars. At the experimental side three-walled osseous defect was prepared for the distal site of the 3rd premolar in use of fissuer bar. Every week, dental floss was stuffed into the osseous defect. Experimental localized periodontitis was induced (an inflammation area). The periodontal tissue on the contralateral side and the experimental side of the mesial side (a non-inflammation area) was kept healthy. The amount of tooth migration was measured once a week by using silicone rubber impression paste and determining the distance between the standard point of the metal cap and the standard point of the apparatus on the study cast models was determined. Then clinical parameters were examined. The experimental period was planned at 8 weeks. In order to avoid the effect of the cheek and tongue pressures, a removable cheek-and-tongue guard was set on the both sides of the lower 3rd premolar, except during examining time. The results obtained were as follows : 1) The experimental side (experimental localized periodontitis) showed that the tooth migration was more as compared with the control side (healthy gingiva). 2) The experimental side showed migration from the inflamed area to the non-inflamed area toward. 3) The amount of tooth migration was correlated with the tooth mobility.

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A histological study on the human mandible was performed, using large celloidin-embedded sections of a total of 63 human mandibles. All the materials were autopsy cases with the range from a 11.8cm crown-heel length fetus to the age of 63 years. The histological study was focused on the chronological as well as developmental changes of the mandibular cortex and the periosteal tissue. Results were summarized as follows : I. Developmental process of the cortex Cortex of a 11.8cm fetus already showed a spongy appearance consisting of fibrous bone. A. Maturation process of the cortex The focal appearance of lamellar bone was noted first in the fibrous bone of a 18.0cm fetus. A 31.0cm fetus had the cortex consisting entirely of a mixture of fibrous and lamellar bones. Moreover, in a 34.0cm fetus, the cortex of the mandibular body was composed entirely of lamellar bone. In a 3-month-old infant, the whole cortex consisted entirely of lamellar bone, and no further histologic changes were observed. From a viewpoint of anatomic sites, the lamellar bones appeared firstly and simultaneously in the body, angle and ramus, and appeared subsequently in the condylar process, incisor region and finally in the coronoid process. B. Consolidation of the cortex A 23.0cm fetus exhibited the focal appearance of band-like tissue in the spongy bone. In a 2-year-old infant the entire contex consisted of a mixture of spongy and band-like tissue. The entire replacement of the cortex by band-like tissue was observed first in the body of 39.5cm fetus and was noted in the whole cortex in a 5-year-old child. No further subsequent changes were seen. From a viewpoint of anatomic locations, the band-like consolidation was noted in the body, ramus, coronoid process, condylar process, incisor region and angle in order of the occurrence. II. Developmental process of the bone in the subperiosteal tissue Eosinophilic and amorphous material which appeared in early fetal period was the most primitive precursor of the bone. This material changed to bone-like tissue, and then to usual new bone tissue. In terms of the chronological relation with formation of the cortex, the above histologic changes in the subperiosteal tissue, including eosinophilid amorphous material, bone-like tissue, usual new bone tissue and usual mature bone tissue, occurred in the period, when the cortex exhibited the maturation process from fibrous and spongy tissue to lamellar and band-like tissue. Moreover, both tissues showed body fusion, resulting in the appearance of usual bone cortex at the age of 5 years. There were no further chronological change. III. Osteoporosis The first osteoporotic change was observed in the incisor region of a 44-year-old case, showing dilated vessels and fibrosis in Harversian canals. Subsequently this osteoporotic changes were noted in the body angle, coronoid process, condylar process and ramus in order of the appearance. Fat cells were also noted in a 58-year-old case.

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Taste buds in circumvallate and fungiform papillae of the mouse were examined with immunohistochemistry, electron microscopy and computer-assisted, three-dimensional reconstruction from serial ultrathin sections. In accord with observations by Murray (1973), four distinct cell types, type I, II, III and basal cells, were identified in taste buds of both papillae. After intraperitoneal injection of 5-HTP, a precursor of serotonin, some taste bud cells showed serotonin-immunoreactivity. The number and location of the serotonin-immunoreactive cells coincided with those of typeIII cells. The taste bud of the circumvallate papilla was made up of 70 to 100 cells. Of these, only the typeIII cells, about 5 to 10 percent of total number of cells, made synaptic contacts with nerve fibers. The typeIII cell made 3 to 5 synapses with 5 to 8 nerve terminals. These synapses were characterized by symmetric membrane thickenings of both the typeIII cell and apposed axon plasma membrane, and by accumulation of numerous small, clear vesicles and dense-cored vesicles in the typeIII cell cytoplasm. These findings clearly indicated a gustatory transducer function for the typeIII cell. The taste bud of the fungiform papilla contained about 40 cells. Similar to the circumvallate taste bud, only typeIII cells made synaptic contacts with nerve terminals and contained both small, clear vesicles and dense-cored vesicles. Synapses in fungiform typeIII cells contained many more synaptic vesicles than those of circumvallate taste buds. One to three typeIII cells, about 5 percent of total number of cells, could be identified within a fungiform taste bud. The typeIII cell made 6 to 8 synapses with 6 to 12 nerve terminals. There were no transitional cells showing intermediate morphological characteristics between cell types. The present results thus contrast with the studies by Kinnamon and his group. Although the exact nature and function of typeI and typeII cells in the taste buds still remains enigmatic, the present study strongly supports the view that there are separate taste cell lines that retain their unique identities, never transforming into one another in the mouse taste buds.

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The present study examined the tissue responses to the different surfaces of titanium endosseous implants in dogs. The implants were cylindrical, each distal half surface of which was polished and mesial half was sandblasted with alumina particles 25, 50 or 125μm in average size. They were inserted in the mandible of dog and periimplant tissues were histologically observed. The results obtained were as follows : 1. The bone contacted all the polished and sandblasted titanium surfaces although there were some differences in contacting area among the surfaces. 2. The polished surface was markedly capsulated by the connective tissue as the experimental period increased and showed more delayed bone maturation than the sandblasted surfaces. 3. In the sandblasted surfaces, durative bone growth was observed and the bone contact was still maintained at 12 weeks. 4. When the density of trabeculae was originally coarse, the surface sandblasted with 50μm alumina showed more bone contact than those with other sizes of alumina. 5. Most of collagen fibrous bundles in the periimplant connective tissue appeared to run parallel to the surface of the implant. From the foregoing results, it is recommended to make the surface of titanium endosseous implant coarse by sandblasting for getting better bone support.

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The wedge-shaped defect (WSD) is frequently observed in the cervical region of tooth, especially on the buccal surface. It has been long demonstrated that WSD might be attributed to the incorrect or excessive toothbrushing. Recently, however, a new concept of WSD induced by occlusal forces has been proposed. The present study examined the stress bearing in the premolar cervical region for applied occlusal forces using a strain gauge in vitro and also observed the existence of WSD and facets in 304 extracted maxillary premolars in order to estimate the possibility of such a cause of WSD. The WSD was found in 198 teeth out of 304 (65.1%), in which 185 teeth (93.4%) had the defect in their buccal cervical region. Regardless of the presence of WSD, one or multiple occlusal facets were detected in most of the teeth. Only 15 teeth exhibited no facet. There was also no WSD in them. Among the teeth having WSD, the frequency of those which were accompanied by the facets at the buccal or lingual triangular ridge and/or the tip of lingual cusp was predominant, indicating a possibility that they might have occurred by a common action of occlusal force. From the strain measurement, on the other hand, it was found that the buccal cervical region was subjected to a considerable tensile or compressive stress when a load was separately applied on the areas showing facets mentioned above. These findings suggest that the occlusal force may cause complicated stresses to be a potential factor inducing WSD in the buccal cervical region.

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Superoxide dismutase (SOD) is a specific enzyme in scavenging superoxide (O_2^-). SOD is noticed in medical science, but there are a few reports on serum SOD activity. Serum SOD activity was assaied for its use in detecting a marker for oral squamous cell carcinoma. Forty consecutive patients with oral squamous cell carcinoma treated in our department between 1987 and 1990 were entered in this study. Blood specimens were collected after informed consent was received from the patients with oral squamous cell carcinoma, oral benign diseases, and helthy control. The results were as follows : 1. The mean serum concentration of SOD activity for patients with oral squamous cell carcinom (18.5±9.9%, n=40) was significantly lower than that of healthy control patients (20.3±10.9%, n=20). 2. In oral squamous cell carcinoma, there was no significant correlation between serum SOD activity and the age, the sex, the tumor size (T classification), Stage calassification, prognosis. However, it was significantly lower in the terminal satge of oral squamous cell carcinoma. 3. The serum SOD activity was significantly lower in the regional lymph node metastasis as compared to the no metastasis of regional lymph node. 4. There was no significant correlation between serum SOD activity and histological differentiation. 5. The serum SOD activity correlated with the grade of malignancy and the mode of invasion. 6. There was no significant correlation between serum SOD activity and the mean serum concentrations of CEA (carcinoembryonic antigen), SCC (squamous cell carcinoma correlated antigen), IAP (immunosuprresive acid protein) In these investigations, the determination of serum SOD activity in patients with oral squamous cell carcinoma may prove to be not useful for early diagnosis. However, These results suggest that the serum SOD activity provides important information of invasion, proliferative activity and regional lymph node metastasis. Therefore, the determination of serum SOD activity is a clinically useful marker for screening of patients with oral cancer.

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In order to evaluate the response of the pulp nerve fibers to diabetes mellitus, 8-week-old male Wistar rats were used. 4 weeks after injection of Streptozotocin (STZ), the upper 1st molars of rats were moved in mesial direction by use of wire springs with about 15g orthodontic force for 1, 3, 7 and 14 days. The histological specimens were investigated by light microscopy. The results were as follows : 1. In the group without orthodontic appliance, there was no distinct difference in pathological findings of the pulp except neurohistological findings between the healthy group and the diabetic group, but the number of osteoclasts existing on the distal root side of alveolus in the healthy group was more than that in the diabetic group. Neurohistologically, degeneration in the pulp nerve fibers gradually advanced through the periods of observation in the diabetic group. 2. In the group with orthodontic appliance, the patterns of tooth movement, which included "Intrusion of mesial root" and "Extrusion of distal root", were similar in both healthy group and diabetic group. Following these tooth movements, there was no distinct difference in pathological findings of the pulp except neurohistological findings in both groups. Neurohistologically, the pulp nerve fibers revealed more severe degeneration day by day in the diabetic group than that in the healthy group, however, the regenerative pulp nerve fibers appeared in the healthy group at 14th day but not be found in the diabetic group. It showed that the regeneration of pulp nerve was later in the diabetic group than that in the healthy group. From the results mentioned above, this study demonstrated that diabetes mellitus influences the reconstruction of the pulp nerve especially during the orthodontic tooth movement. Therefore, it was suggested that diabetes mellitus might play an important role for determining vitality of the dental pulp in clinical diagnosis after orthodontic treatment.

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Masticatory muscle activity is affected by various environmental changes inside and outside the oral cavity. The effects of an increase in the occlusal vertical dimension and those of the occlusal contact on masseter muscle activity were evaluated. Masseter muscle activity during the whole day (24 hours) was analyzed using a "whole day electromyogram recording and analysis system" with a bite plate either for the anterior teeth area (type A plate) or that for all dental arch (type F plate), or without any plate. Prior to electromyography, the subjects performed maximum clenching, Setting with 1/16 (level 1), 1/4 (level 2), 1/2 (level 3), and 3/4 (level 4) of the maximum potential as reference levels. The muscle activity time and frequency per hour were examined during the whole day, arousal, and sleep and analyzed by two-way analysis of variance. 1. Only at level 1, significant differences were found in the muscle activity time and frequency during the whole day, arousal, and sleep among the subjects. 2. The muscle activity time during sleep at level 1 was significantly decreased in suing a type A or F plate, compared to that in without using any plate. 3. At levels 2 and 3 during sleep, significant differences were found in the muscle activity time and frequency only among the conditions ; muscle activity was significantly decreased using a type A or F plate than without using any plate. 4. At level 4, no significant differences were found among the subjects or among the conditions. 5. No significant difference was found between the types A and F plates at any levels during the whole day, arousal, or sleep. These results showed a significant decrease in masseter muscle activity during sleep with an increase in the occlusal vertical dimension using a bite plate. No siginificant differences were observed among masseter activities during the whole day, arousal, and sleep between using type A and F plate. However, comparison of the type A and F plates showed a slightly more marked decrease in muscle activity using the type A plate. This indicates that the presence or absence of molar occlusal contact affects masseter activity.

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To evaluate the medically compromised patients more exactly, we investigated the 470 of inpatients, aged more than 18 year old, of the Kyushu Dental Collage Hospital by refferring their laboratory data together with taking their histories. They were 235 males and 235 females, and their mean age was 47 year old. Past histories and present illness revealed that 180 or 38% of the patients were medically compromised. Among these 180 patients, hypertension was most frequent, which was followed by liver diseases and diabetes mellitus. Sixty-eight or 38% of them had 2 or more medical illness. The mean age of the medically compromised patients was 55±17 year old, which was significantly higher than that of the other patients (40±17, p<0.001). On the other hand, measured blood pressure was abnormally high in 33% of the patients, fasten blood glucose level was high in 17%, and liver dysfunction was observed in 21%, which were far higher than the frequencies obtained by the history taking. According to the categories of dental diseases, some characteristics of the laboratory findings were observed, such as higer blood pressure, higher frequency of hypoproteinemia or hypoalbuminemia, and lower hemoglobin concentration in inflammatory diseases and malignant tumors. Our results suggest that medically compromised patients seem to be more common in dental hospital and we should pay more attention on the results of their laboratory examinations.

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Many investigators indicate that there are differences in human oral traits by ethnicity and sex. The aim of this study is to clarify the traits of Central American Indian Jicaques' oral cavity. Plaster models were taken from 16 males and 17 females of the Jicaques tribe aged 16 years and older, and were measured. Each measured value of Jicaques' dental arches and palates was compared between males and females. And 3 values of the Jicaques ware also compared with those of Taiwan Aboriginals (Ami, Bunun, Paiwan and Rukai tribes), Taiwanese and Japanese. Upper anterior dental arch length of the Jicaques was significantly greater in the males than in the females. In the males, upper anterior, posterior and lower anterior dental arch lengths of the Jicaques were significantly shorter than those of the Taiwanese and Japanese. In the females, upper anterior dental arch length of the Jicaques was significantly shorter than that of the Ami, Bunun, Paiwan, Taiwanese and Japanese, and upper posterior, lower anterior and posterior dental arch lengths of the Jicaques were significantly shorter than those of the Japanese. Upper anterior, posterior and lower anterior dental arch breadths of the Jicaques were significantly greater in the males than in the females. In the males, dental arch breadth measurements were significantly greater at upper anterior and posterior regions in the Jicaques than in the Taiwan Aboriginals, Taiwanese or Japanese, and were significantly greater at lower canine region in the Jicaques than in the Taiwanese, Japanese or Taiwan Aboriginals except Rukai tribe. In the females, dental arch breadth measurements were significantly greater at upper anterior region in the Jicaques than in the Taiwanese, Japanese or Taiwan Aboriginals except Bunun tribe, and were significantly greater at upper posterior and lower canine regions in the Jicaques than in Taiwan Aboriginals, Taiwanese or Japanese. Length of dental arch of the Jicaques was significantly greater at upper first premolar, lower canine and lower first premolar regions in the males than in the females. Anterior and posterior palatal heights and length of sutura palatina mediana of the Jicaques were not significantly different between males and females. Posterior palatal height was significantly lower in the Jicaques males and females than in the Taiwan Aboriginals or Japanese. Palatal arch length of the Jicaques was significantly greater at the first molar region in the males than in the females. Palatal breadths of the Jicaques were significantly greater at the first and second premolar, and first and second molar regions in the males than in the females. Mandibular alveolar breadths of the Jicaques were greater at the first and second premolar, and first and second molar regions in the males than in the females. Dendrogram based on the seven dimensions of dental arch and palate was constructed by cluster analyses (group average method). Three major clusters were found. In the males, the first contained the Ami, Bunun, Paiwan and Rukai, and the second contained the Taiwanese and Japanese, and the third contained the Jicaques. In the females, the first contained the Ami, Bunun, Taiwanese and Japanese, and the second contained the Paiwan and Rukai, and the third contained the Jicaques. These results indicate that Central American Indians Jicaques differ much from Taiwan Aboriginals, Taiwanese and Japanese.

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A statistical analysis of new patients who visited Department of Preliminary Examination, Kyushu Dental College Hospital during the 9 years period from April 1985 to March 1994 is presented. Statistics on a total of 48, 108 new patients was collected and analyzed regarding number of patients, sex, age, type of medical insurance, examining department and referral patients. The results were as follows : 1. The number of new patients was 4, 922 in 1985, and it increased gradually to 5, 615 in 1991, but since then decreased to 5, 308 in 1993. But, mean number of patients per day increased in 1993. The number of females was about 1.5 times as large as males each year. 2. More new patients visited in March, July and August than other months, and only a few visited in winter every year. 3. The percentage of new patients was the largest in 0-9 years old group in 1985, and it decreased gradually. In 1989, the percentage of new patients was the largest in 20-29 years old group, and it increased gradually. 4. The percentage of insurants, insurant dependents and non-insurant patients hardly changed every year. 5. The examining department most often visited was oral surgery : the second, combined conservative dentistry and periodontology and endodontology ; the third, pedodontics ; the 4th, prosthetic dentistry ; the 5th, orthodontics ; the 6th, preventive dentistry ; the 7th, dental anesthesiology ; and the 8th, was dental radiology. The percentage of new patients in oral surgery was 53.0% in 1985, and it increased gradually to 62.8% in 1993. 6. The percentage of referral patients was 32.5% in 1985, and increased year by year. In 1993, the percentage of referral patients was 45.6%.

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The incidence of difficult-to-detect, subclinical lesions in the oral cavities was examined, using CR orthopantomography. The subjects for this study were 193 students at the Kumamoto University School of Medicine (174 males and 19 females). Their ages ranged from 23 to 42 years (mean : 24.9 years). Among all orthopantomograms taken of these subjects, 80.3% contained some radiographic abnormalities. However, only a very small percentage of the subjects were found to have the types of lesions which are difficult to detect during ordinary oral checks, yet require treatment. The results indicate that screening using this low X-ray dose CR system is useful in detecting subclinical lesions of the oral cavity, without exposing medically compromised patients to the risk of infection.

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