The philosophy of Oriental medicine differs markedly from that of modern Western medicine. The concepts and logic of Oriental medicine are shared by East Asian countries and are based on ancient Asian medical physiology established as long as 3000 years ago. Some dental specialists are now advocating the use of Oriental medical concept in dental practice. In Oriental medicine, the oral cavity is considered organically associated with the rest of the body;the teeth and oral cavity are components of the entire network of organs rather than isolated body parts. In this paper, we compare the basic concepts of Oriental and Western medicine, and discuss how to concepts of Oriental medicine apply to dentistry and how to diagnose patients in accordance with these concepts. On the basis of detailed descriptions of the anatomy of the jaw and oral cavity, treatment is determind for dental pain, periodontal disease, temporomandibular dysfunction, and extractions under acupuncture anesthesia.

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We investigated the effect of green tea on cellular proliferation and telomerase activity in the human oral squamous cell carcinoma cell lines HSC-4 (well differentiated) and HSC-3 (poorly differentiated). HSC-4 and HSC-3 cells were incubated following treatment with or without (-) -epigallocatechin-3-gallate (EGCG), and with or without (-) -epicatechin (EC), at various concentrations. Although EC did not significantly inhibit cellular proliferation in either cell line, EGCG inhibited it in a dose and time dependent manner. Although the telomerase activity of HSC-3 cells was not inhibited, that of HSC-4 was inhibited in a dose dependent manner. When HSC-4 cells were treated with EC in the presence of EGCG, there was a synergism in the inhibition of cellular proliferation, telomerase activity and the expressions of hTERT and MMP-9 mRNA. These results indicated that antitumor effects of green tea are closely related to telomerase activity in well differentiated oral squamous cell carcinoma.

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To assess the clinical application of bridges made of castable calcium phosphate crystalline ceramics, we inserted three-unit fixed bridges made by the one-piece cast method in 30 patients and for three months observed the prostheses, the pulpal status, secondary caries, the soft tissues, and other side effects. We found no serious pulpal pain or secondary caries in the abutment teeth, and no serious gingivitis at the gingival margin or under the pontic. All bridges had acceptable fit at the margins, good color and transparency, and no cracks. None of the bridges had become dislodged and no other side effects were observed. However, one bridge fractured at the mesial and distal connectors about 2 weeks after placement. It had a thickness of 2.5 mm at the mesial connector.As 29 of the bridges provided satisfactory service, we concluded that castable calcium phosphate crystalline ceramics are clinically safe and effective for use as three-unit fixed bridges, when the bridge has a thickness of at least 3 mm at the connectors.

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The purpose of this study was to investigate the influences of stimulation coils and occlusal force on elicitation of motor evoked potentials (MEPs) in the masseter muscle by transcranial magnetic stimulation (TMS).Five healthy male subjects were asked to clench with light or strong force to record the MEPs in the bilateral masseter muscles by TMS with three different coils (round, figure-eight and double cone). Stimulation strengths ranged from 30 to 70% of the maximum output for each coil. We found that the:MEPs recorded in the ipsilateral masseter muscle had short latency (about 3.0 ms) and these in the bilateral masseter muscles had long latency (about 8.0 ms). MEPs in the contralateral masseter muscle were elicited only in heavy clenchings. The double cone coil elicited the MEPs highest. These results suggest that cortical MEPs by TMS were elicited most easily with heavy clenchings and in combination with the double cone coil.

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We evaluated the laser weldability of dental cobalt-chromium alloys using 7 commercial casting cobalt-chromium alloys and one commercial wrought alloy. Spot welds were formed on the surfaces of specimens with a pulsed YAG laser. Laser weldability was then evaluated by microstructural observation of the base metals and welds with an optical microscope, observation of the fractured surface with a scanning electron microscope, elemental analysis with electron probe microanalyzer (EPMA) and measurements of changes in the hardness. Cracks and porosity had been generated in the laser welds of the cobalt-chromium alloys. Observation of the microstructure and the fracture surface suggested that the cracks were the solidification cracks. The cracks were probably caused by the addition of such elements as silicon and carbon. Although the laser weld in the wrought cobalt-chromium alloy had decreased hardness, neither cracking nor porosity was generated.

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Most of oral infectious diseases that we, dental scientists, study are due to bacteria indigenous to the oral cavity or other weak pathogenic bacteria. Recently, most of infectious diseases are due to weak pathogenic bacteria, for example, Staphylococcus aureus (involved methicillin-resistant Staphylococcus aureus, MRSA), Legionella, Serratia, vancomycin-resistant Enterococcus (VRE). The first feature of diseases infected with weak pathogenic bacteria is the opportunistic infection, because these are weak pathogens. Secondly, it is difficult to determine caused bacteria. Thirdly, in the hospital infection, to acquire the resistance to antibiotics contribute to pathogenicity. While strong pathogenic bacteria shows pathogenicity by exotoxins, weak pathogenic bacteria has a complex mechanism, which is not able to explain by a virulence factor, but by multi factors. In oral infectious diseases, dental caries, periodontal diseases are major, and most of them are caused by Streptococcus mutans and Porphyromonas gingivalis. And from the other oral infectious diseases, Prevotella intermedia/nigrescens were frequently isolated. These have various virulence factors, for example in relation to entry, attachment, evasion of host defense, cause damage to host cells, spread, and these contribute to diseases.In contemporary, compromised hosts have increased and environment is very hygienic, so infectious diseases of weak pathogens are not despised.

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Nosocomial infection means infection acquired in medical facilities. As nosocomial infection is included among the opportunistic infection, immunocompromised host are infected easily. In the pathogen of nosocomial infection the resistant bacteria against various antibiotics and disinfectants cause nosocomial infection mostly, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and multidrug resistant Pseudomonas aeruginosa (MDRP). Resistance mechanism in MRSA and VRE are variation or alternation of antimicrobial targets. MRSA acquire resistance mechanism by production of penicillin-binding protein 2´ coded mec gene, and VRE acquire by aynthesis of _D-Alanyl^4-_DLactate^5 or _D-Alanyl^4-_D-Serine^5 coded van gene. MDRP show multidrug resistance by various resistance mechanism, that is production of inactivated enzyme, variation or alternation of antimicrobial targets, low outer membrane permeability, accelation of efflux systems and biofilm formation. The pathogen in nosocomial infection have a great variety of resistance mechanisms. In this symposium, I discuss nosocomial infection about MRSA, VRE and MDRP infection broke out even in dentistry and those resistance mechanisms.

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Most of endodontic incurable cases occur by the bacterial infection. The conventional root canal therapy may not completely remove bacterial infection. "Chair-side anaerobic incubation system" based on "the apical treatment" will facilitate that the cause of incurable endodontic cases is determined and removed. It is possible that the endodontist obtains useful information for the treatment by the bacteriologic test of "chair-side anaerobic incubation system". Local administration of antibiotics based on the antibiotic sensitivity test should remove the infectious bacteria from root canal and periapical area. From the above fact, the author considers that "chair-side anaerobic incubation system" becomes the useful therapy for the endodontic treatment.

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I studied surface structural differences in the enamel of deciduous teeth. Specimens 3 mm in diameter were prepared from two types of extracted human deciduous teeth using a hollow core drill. One group had complete roots without any resorption, and the other had roots that were completely resorbed. The enamel surfaces were highly polished using standard methods. The samples were observed by using atomic force microscopy (AFM), and were then cut perpendicularly with a saw for SEM observation. It was possible to observe the surface structure of both types of enamel at the cryatal level, and lesions could be formed in vitro for both. Enamel crystals on the polished surface of the teeth without root resorption were larger than those of teeth with root resorption. Subsurface lesions of teeth without root resorption were different from those with complete root resorption.

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Cerebrospinal fluid (CSF) drainage pathways from the rat brain were investigated by injection of 30 μL of lndia ink into the lateral ventricle. Following injection of the ink, the deep cervical lymph nodes and nasal mucosa were selectively blackened within 30 min. Carbon particles in the subarachnoid space beneath the olfactory bulbs passed through the cribriform plate and drained into lymphatics in the nasal submucosa. Although ink was distributed along the subarachnoid space of the optic nerves, no lymphatic drainage from these structures was identified. The nasal route was the only direct connection between cranial CSF and lymphatics.

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We investigated immunohistochemical expression of pRb, cyclin D 1, and cdk 4 in rat tongue carcinoma induced by 4-nitroquinoline 1-oxide. pRb expression in carcinoma decreased compared with that in dysplastic lesions, while expression of cyclin D 1 and cdk 4 increased gradually during the course of carcinogenesis. Phosphorylation of pRb was analyzed by immunoblotting using the G 3-245 antibody, which recognizes both phosphorylated (pp 110^RB) and unphosphorylated pRb (p 110^RB). Although expression of pp 110^RB notably increased in the dysplastic membrane, it almost disappeared in carcinoma. p 110^RB was also expressed in control and dysplastic membranes, but not in carcinoma.In conclusion, there was a decrease of pRb and an increase of cdk 4 and cyclinD 1 in the premalignant stage. A decrease in the amount of pRb and an increase in its phosphorylation may prevent G 1 arrest and consequently accelerate proliferation of chemically injured cells.

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We attempted to develop a detection system for human telomerase RNA (hTR), β-actin mRNA and granzyme A mRNA using a single section of human gingival tissue, and to discuss the relationship between immunohistochemical staining and RNA expression. One 4μm frozen section and one 4μm paraffin section of human gingiva were examined by RT-PCR and immunohistochemical staining. RT-PCR analysis of the three RNAs was accomplished by appropriate combination of the design and selection of primers. Actin and telomerase were strongly detected in all sections examined irrespective of the degree of inflammation in the gingival tissue, although expression of granzyme depended on the extent of the inflammation in the epithelial region. Samples with stronger inflammation had greater granzyme activity.

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We examined the production of monoclonal antibodies (MoAb) against human γδT cells to understand the role these cells play in the pathogenesis of periodontal disease. Stimulation of human peripheral lymphocytes with solid-phase anti-CD 3 antibody and soluble IL-2 produced a 100-500-fold increase that included about 50% γδT cells in the two week culture. These γδT cells were used as an antigen to produce the MoAb. Ten MoAbs were isolated and one of them, MoAb 1, was characterized immunohistochemically using gingival sections with periodontal disease, and compared with commercially available anti-γδT cell antibody.

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I investigated changes in mandibular movement and tooth position caused by mandibular lip bumper treatment. Ten patients who received lip bumper therapy were studied. Study models, cephalograms, and mandibular movement were recorded prior to and 6 months after lip bumper treatment. Three angles of projection (AP) were recorded for the angle between the path of closure and the FH plane. They were the frontal, horizontal and sagittal projections. Changes for the dental values and for each AP before and after treatment were compared using the paired t-tests. The relation between these changes were evaluated by Pearson's correlation analysis. All measured items for the dental values increased significantly in all cases after 6 months of lip bumper treatment. I also found a significant relationship between changes in arch width and the frontal and horizontal AP. This study showed that with lip bumper treatment, changes in arch development, especially arch width, resulted in masticatory movement changes in the lateral dimension.

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We investigated the influence of masseter muscle fatigue on motor evoked potentials (MEPs) by using transcranial magnetic stimulations (TMS). The experiment was carried out with continuous or periodic voluntary contractions. The latency and amplitude of the MEPs was measured. No changes were found in the latency of the MEPs. As fatigue advanced, the amplitude of the MEPs decreased. The continuous and periodic voluntary contractions produced different decreases in the amplitude of the MEP. The results suggest that TMS is effective for observation of masseter muscle fatigue.

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We investigated the relationship between emotional stress and autonomic nervous response during local anesthesia. Twenty-four healthy subjects were divided into two groups. For both groups the dentist administering the local anesthesia was changed just before administration. One group was informed this change would be made, and the other was not. Blood pressure and heart rate were measured continuously in all subjects. We found that anxiety induced by the change of dentist influenced blood pressure and heart rate more among the patients who were not informed. This suggests that it is important to inform the patient of procedural changes he does not anticipate.

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I investigated the laboratory conditions needed for good dimensional accuracy of calcium phosphate crystalline ceramic bridges. I examined how the signal to noise ratio and sensitivity of the measurements, and orientation of the retainers influenced dimensional changes. The optimum conditions that produced the minimum amount of disruption in these factors was confirmed by the analysis of variance. It was found that the optimum dimensional accuracy for the bridge could be obtained by using a casting ring 45 mm in diameter, ring liner, an investment of medium expansion, and a ratio of 50% liquid.

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Extracts were obtained by gyrating cylindrical specimens of typeIII gold, gold-silver-palladium, and silver-indium alloy on a disk-shaped specimen of the same alloy at 240 rpm for 7 and 14 days. The amount of Au, Pd, Ag, Cu, In and Zn released was measured using inductively coupled plasma spectrometry. The cell viability of extracts and filtrates was evaluated by neutral red and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide assays. The six metals were detected in the extracts. Cu was the most easily dissolved. Ag and Pd were not detected in the filtrates. Cell viability of the extracts showed a significant decrease in silver-indium alloy, compared to typeIII gold and gold-silver-palladium alloys. Cell viability increased after filtration in every extract. These results indicate that dynamic extraction might be useful in evaluating the dissolution and cytotoxicity of metallic biomaterials that mimic stress-bearing restorations.

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