We carried out biochemical investigations into changes in tumors induced by subcutaneous implantation of discs of lanthanum and zirconium oxide containing hydroxyapatites. Fibril collagen from tumor tissues was compared with fibrous capsules formed around discs of various apatites, based on cross-links and types.
     The amount of collagen as hydroxyproline in the tumor was less than in the capsules. Furthermore, the collagen in the tumor could be solubilized by pepsin digestion. Although there was no quantitative difference in the hydroxylation ratio of proline among tissue collagens, the hydroxylation ratio of lysine in the tumor collagen was higher than in the capsule collagens. Various methods for analyzing the type of pepsin-solubilized collagen, including differential salt precipitation, amino acid analysis and SDS-PAGE, revealed that tumor collagen consisted mainly of type I, and small amounts of types III and V. Although the capsule collagens included types I and III, type V was not present. Cross-links in the insoluble collagen was investigated using three different methods: modified amino acid analysis, HPLC and fluorescence analysis. The tumor collagen contained considerable pyridinoline and histidinoalanine as non-reducible cross-links. No difference was seen among tumor and capsule collagens in the furosine level as indicated by the early-stage of non-enzymatic glycation, or in the fluorescence intensity as indicated by the late-stage, as the tumor had low values relative to those for the capsule collagens.
     The results confirmed the biochemical characteristics of fibril collagen surrounding the implanted material. These characteristics of collagen in capsules and tumors may be related to the production and progress of the tumor.

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     Dental personnel often inhale abrasive dusts of metal and resin during treatment or laboratory work. In order to investigate lung pollution among dental personnel, we used the thermal neutron radioactive analysis method to quantitatively measure the density of several metallic abrasive dusts present in the lung of a dental technician who had died of lung cancer. We also measured the metallic dusts in a nondental office worker who had died of hepatoma. The lung of the dental technician had a considerably higher density of Au, Co, Cr, V and Zn than the general population. These substances are very common in dental materials, and were still present in the lungs of the dental technician ten years after retiring.
     It is hoped that these findings will alert dental personnel of the possible effects of these substances on the lungs and encourage them to improve environmental hygiene in dental clinic and laboratories.

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     In order to clarify the three-dimensional condylar movement in children, measurements were made using the Axi-Path II Recorder on adults and on children in Hellman's dental stages III A and III B. Averages were obtained for these two groups and the results were compared.
     The manipulation technique was useful in obtaining the location of the finite hinge-axis position. Average values were obtained for condylar movement in children in Hellman's dental stages III A and III B. The excursive tracing of the inclination with the axis-orbital plane was smaller in children than adults. The t-test showed no significant difference between the two groups in the amount of condylar movement during protrusion and mediotrusion. However, on opening, the adults had significantly greater values than the children. When the side shift of the balancing side condyle was compared on the left and right, the children showed no significant difference in motility and mobility. In adults, however, the right condyle had significantly greater values than the left. On the right side there were no significant differences in side shift between adults and children. However, on the left side, although the mobility was essentially the same for the two groups, the motility was significantly smaller for the adults.
     These values may be useful in preventing imbalances between anterior and posterior guidance during dental treatment in children.

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     We examined hemagglutination activities of various fimbrial types of Prevotella intermedia and characterized the hemagglutinins.
     Almost all strains tested possessed agglutinating activity with rabbit erythrocytes. No relationship between hemagglutination activity and DNA homology group or fimbrial type was recognized. All strains with no fimbriae showed a wide range of hemagglutinating activities (from titer 2 to 32). All strains except two lost activities after heat treatment at 70°C for 10 min. Hemagglutination activity of the remaining two strains was eliminated after exposure to heat at 100°C for 10 min. Trypsin, chymotrypsin, protease and lysozyme either eliminated or reduced the hemagglutination activities of 14, 13, 12 and 5 strains, respectively, of the 18 examined. However, β-glucosidase and β-galactosidase did not affect hemagglutination activity in any of the strains. Of 17 sugars tested, only D-glucosamine caused hemagglutination inhibition of Prevotella intermedia, and this was in only one strain, E8, which was in the ATCC 33563 group.
     Morphological changes in the cell surface of strain O2, which was D-glucosamine-resistant, trypsin-sensitive and carrying type A fimbriae, were studied after treatment with trypsin. With negative staining, trypsin-treated cells lacked the folds characterizing gram-negative bacteria. However, type A fimbriae still remained after treatment with trypsin. In thin-sectioned micrographs, treated cells partially lost the dense outer membrane layer. In SDS-PAGE, trypsin-treated cells lacked a protein of about 27 kDa compared with untreated cells, suggesting that hemagglutination of that O2 strain may result from this protein on the outer membrane, but not from type A fimbriae.
     These results and previous data indicate that there are many types of hemagglutinins on Prevotella intermedia.

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     I investigated the effect of stationary magnetic fields on experimental tooth movement. Stationary magnetic fields have been used in orthodontic tooth movement to achieve clinical effects without discomfort.
     One hundred and twenty 42-day-old male Wistar rats were placed in the experimental apparatus for 7 days prior to the experiments. Orthodontic appliances with a buccal force of 20 g were bonded to the right maxillary first molars, and the rats were placed in the holding devices. Stationary electric magnetic fields of maximum intensity 60 millitesla were used. Control animals received similar appliances without magnetic fields. The animals were killed at 3, 7 and 10 days after initiation of tooth movement. The distance of the movement was measured and paraffin sections 6 μm thick were cut from the right maxillary molars.
     The distance of tooth movement was not significant at 3 days. After 7 and 10 days, the distance increased significantly, and undermining resorption of the alveolar bone was observed in the pressure area. Extension, hyperemia of blood vessels and active bone resorption was observed around areas of hyalinization.
     The results suggest that stationary electric magnetic fields promote tooth movement.

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     Senescence accelerated mouse (SAM) show various signs of accelerated aging, including degenerative joint disease. To determine whether SAM can be an animal model of degenerative joint disease, we evaluated their craniofacial morphology and analyzed differences in age-related morphological changes between accelerated senescence prone mouse (SAMP) with accelerated senescence and accelerated senescence resistant mouse (SAMR) having normal senescence.
     Forty-three male SAMP1//Odu were used as the experimental group, and 39 male SAMR1/Odu were the controls. The mice were periodically weighed. Lateral x-ray films of the head were obtained at 5, 9, 14, 21, 29 and 36 weeks of age, and analyzed by Persson's method.
     Body weight rapidly increased until 9 weeks of age in both SAMP1//Odu and SAMR1/Odu, with no differences between the two.
     The SAMP1//Odu showed significantly higher values (p<0.005) in Ba-So at age 5 weeks, N-A and PoBa/PoE at age 9 weeks, Ba-Pr, Ba-So and PoBa/PoE at age 14 weeks, Ba-Pr, Ba-So and PoBa/PoE at age 21 weeks, Ba-Pr at age 29 weeks and Ba-Pr, Ba-So, PoBa/PoE, AN/PoE and AN/SoE at 36 weeks of age.
     These results suggest that morphological differences in the jaws, face and cranium between SAMP1//Odu and SAMR1/Odu are not associated with growth and development, but are due to changes in Ba position at 5 weeks of age. Thus, the two strains already had morphological differences at 5 weeks of age and showed no age-related differences as had been reported in SAMP3 and SAMR. No definite conclusions can be made since pathological examinations were not performed in this study. However, unlike SAMP3, SAMP1//Odu may not be suitable for an animal model of temporomandibular joint osteoarthritis.

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     We investigated the spread of methicillin-resistant staphylococci (MRS) in Osaka Dental University Hospital by examining the nasal carriages of the medical staff and patients, and testing the antimicrobial susceptibility of the isolates. MRS were isolated from three inpatients and a location in a hospital room, but not from any of the medical staff or outpatients.
     MRS were classified into 9 types according to antibiotic sensitivity. All strains were susceptible to chloramphenicol and vancomycin. The sensitivity pattern of the isolates to antibiotics suggested that cross infection was occurring in the hospital.

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In order to stereographically investigate the degradation of dentin caries in deciduous teeth, we used laser scanning microscopy (LSM) to observe these lesions stained with Villanueva. Fine tomographical pictures of the dentin caries were obtained even at high magnification, regardless of section thickness. Carious dentin lesions were stereographically observed by computer imaging of the tomographic pictures. Dentin caries proceeded along the dentinal tubules and their lateral branches. Destruction of intertubular dentin and compression of the tubular wall caused enlargement or the dentinal tubules. The use of LSM permitted detailed observation of carious lesions in deciduous teeth.

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In order to elucidate the characteristics of the junctional epithelium (JE), I investigated lectin-binding patterns in JE derived from reduced enamel epithelium and in tissue regenerated from oral gingival epithelium (OGE) after gingivectomy. A peanut agglutinin (PNA)-positive reaction was observed in the cell membrane of ameloblasts in reduced enamel epithelium. PNA reacted with the JE regenerated from OGE after gingivectomy, but not with the basal cells. However, Ulex europaeus-I did not reacted with cell membrane through the JE. Thus, the cell membrane surface of the regenerated JE seemed to have complex carbohydrates similar to those present on the ameloblast surface. Regenerated JE displayed differentiation and morphology different from OGE, even though it was derived from epithelium.

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We examined hemagglutination activity of various fimbriae-types of Prevotella intermedia and characterized the hemagglutinins. Trypsin either eliminated or reduced the hemagglutination activities of 22 of the 25 strains examined. The remaining three strains were resistant to trypsin. Hemagglutination activity of these strains remained after exposure to heat at 60°C for 10 min, although it was either eliminated or reduced in the others. Of 17 sugars tested, only D-glucomamine caused hemagglutination inhibition of Prevotella intermedia, and this was in only two strains. D-Glucosamine-sensitive strains and trypsin-sensitive strains possessed type A or AL fimbriae. These results indicate that there are at least three different kinds of hemagglutinins on type A and AL fimbriae of Prevotella intermedia.

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I examined the production of the hydrolytic enzymes β-lactamase, DNase, hyaluronidase, chondroitin sulfatase, lipase, lecithinase, collagenase trypsin, chymotrypsin and viscous material in clinical strains isolated from periodontal pockets with and without acute inflammation.
In pocket bacteria with acute inflammation, the distribution of collagenase, DNase and trypsin producers was 30.4, 22.6 and 17.6%, respectively. Other hydrolytic enzyme-active bacteria were found in less than 5% of all isolates. P. gingivalis predominated as collagenase (33.9%), DNase (35.7%) and trypsin (82.9%) producers, respectively. The ratio of the above enzyme producers was lower in cases without acute inflammation than in active cases, but higher in cases without acute inflammation than in acute periapical periodontitis cases, indicating that pocket bacteria have considerable potential to induce acute inflammation.

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I investigated the polymerization shrinkage of composite resin restoration materials and stress created in the cavity preparations by this shrinkage as a function of cavity depth, area of adhesion and pressure welding. Various cavity depths were prepared in multi-crystalline glass. There was an increase in gap formation as the cavity depth increased and as the consistency of the composite resin decreased. Gap formation was greater with light-cured than chemically-cured resins. Pressure welding was not effective in decreasing gap formation. Crack formation was influenced by depth of cavity preparation and mode of curing, but not by consistency of the composite resin or pressure welding.

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I carried out biochemical and physicochemical investigations on the adsorption of salivary proteins to synthetic hydroxyapatite (HAp) using salivary proteins fractionated from whole human saliva by gel filtration. Correlation between the adsorption volume of protein and the zeta potential of HAp indicated that at low concentrations the salivary protein adsorbed on the HAp surface with a monolayer of the Langmuir type, and with a multi-layer at high concentrations. The residues of basic and hydrophobic amino acids decreased in the shlivary protein solution after addorption. These results indicate that the adsorption of salivary proteins to HAp is dependent on electrostatic and hydrophobic interaction.

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