In order to investigate the optimal timing for cryochemotherapy, we examined the vascular changes after cryosurgery in the cheek mucosa of the golden hamster. Blood flow was restored in the arterioles and venules immediately after thawing. It continued for 120 minutes after the operation, at which time vascular stases were observed in the arterioles, venules, and capillaries. Sluggish flow continued in the small arteries and veins even after 180 minutes.
We examined the optimal timing for administration of intravenous anticancer agents during cryosurgery by measuring the drug concentration in the tissue undergoing freezing. There was high uptake concentration and trapping of Peplomycin (PEP) in frozen and surrounding marginal tissues when the drug was administered 15 minutes before cryosurgery.
The concentration of Cisplatin (CDDP) remained high in the surrounding marginal tissues for 240 hours, ranging from 0.1-0.2mcg/g. The marked uptake of anticancer agents in the affected tissue was not observed in the group where the drug was administered after cryosurgery. Nedaplatin was cleared from the surrounding tissue more rapidly than CDDP. Shiaka Igaku (J Osaka Odontol Soc) 1997 Mar；60(1)：1-12．

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We carried out clinical, radiographic and histologic investigations on the effect on induction therapy of external radiotherapy combined with chemotherapy using Bleomycin (BLM) or Peplomycin (PEP) for squamous cell carcinoma of the mandibular gingiva. The induction therapy generally included a total radiation dose of 30 Gy given in 15 fractions over 3 weeks together with either a total BLM dose of 90 mg given in 6 fractions, or a total PEP intravenous injection of 45 mg given in 9 fractions.
This therapy seemed effective as a preoperative treatment for mandibular gingival carcinoma because it resulted in long-term remission of the tumor in many cases, even when used alone without adjunctive treatment. This effectiveness was confirmed in histological examination on resected tissues. Shika Igaku (J Osaka Odontol Soc) 1997 Mar； 60(1)：13-24．

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We investigated the dynamic changes that occur in the cranium when occlusal and masticatory forces are not imparted on the jaw bones because of loss of teeth, even though there is opening and closing of the mandible. Electrical stimulation (30 or 40V) was applied to the central region of the masseter muscles on both sides of anesthetized adult Japanese monkeys fixed in a standing position, and the strains in the temporal bone, sphenoid bone, zygomatic bone, zygomatic arch, maxilla and mandible were measured when the animals were made to occlude. The experiment was carried out on three groups: 1) when they occluded on crowns that had not been reduced (controls), 2) when the crowns of all the maxillary and mandibular molars were reduced and they were made to open and close without any contact on the molars, although the anterior teeth were in contact (Group A), and 3) when the maxillary and mandibular anterior teeth were also reduced and they were made to open and close without contact of any of the teeth (Group B). Strain in the bones at this time resulted only from the forces of muscle contraction.
The amount of strain decreased in every bone when all the maxillary and mandibular crowns of both the anterior teeth and molars were reduced. The principal strain decreased in the temporal bone, sphenoid bone, zygomatic arch, maxilla and mandible to 52, 32, 40, 47 and 39%, respectively, compared with the controls. In contrast, strain in the zygomatic bone was little changed compared with the controls (94%).
Compared with the controls, the direction of the tensile component of the principal strain when teeth are lost is in the anteroposterior direction in the mandible, maxilla and zygomatic bone, while it is in the vertical (body) axis direction in the temporal bone and zygomatic arch. It is along the vertical axis in the sphenoid. That is to say, it rotates in the anteroposterior direction for the facial bones, and along the vertical (body) axis for the cranial bones. At that time, the center of rotation is in the sphenoid, because the direction of principal strain of this bone varies little regardless of the conditions under which opening and closing motions are carried out. Therefore the sphenoid bone creates a dynamic balance left, right and in the anteroposterior directions, while at the same time, playing an important role in transmitting the direction of displacement of the cranium to the cervical vertebrae. Shika Igaku (J Osaka Odontol Soc) 1997 Mar； 60(1)：25-34．

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We investigated the supply and demand for dental services in Osaka during 1993 to determine factors influencing the sufficiency rate for these services. The sufficiency rate for dental services was defined as the amount of treatment supplied divided by the amount of dental disease during one year. The demand for dental treatment was estimated as the amount of dental disease in 1993 from data of seven reports on national surveys of dental diseases between 1957 and 1993. Dental treatment supplied was estimated from dental treatment performed in 1993 from clinical records of 6,000 patients who visited six private dental offices in Osaka.
The sufficiency rates were 96.97% for untreated teeth and 34.38% for missing teeth. For periodontal disease the rates were 23.42% for instruction of oral hygiene, 52.55% for scaling, and 60.57% for curettage and flap-operations. We then used multiple regression analysis to statistically analyse factors affecting the sufficiency rate for dental services. We found that increases in the number of dental offices increased the sufficiency rate for decayed teeth, but not for missing teeth. Shika Igaku (J Osaka Odontol Soc) 1997 Mar； 60(1)：35-44．

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We studied surface changes in dental enamel and dentin by resulting from laser irradiation utilizing Nd: YAG and CO₂. Polished surfaces of enamel and dentin were prepared as samples. The structure of the laser irradiated enamel and dentin surfaces were observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM), and analyzed by electron spectroscopy for chemical analysis (ESCA). AFM observations demonstrated contiguity of the enamel crystals, which gradually melted with increasing laser power. The rounded dentin crystals became square with increases in the laser power. Nd: YAG laser irradiation produced greater changes than did CO₂. It seems that laser irradiation should enhance acid resistance of the surface as a result of decreases in the surface area of the enamel and dentin crystals. SEM observations showed that the irradiated enamel surfaces were smoother than those of the controls. ESCA analysis of the laser irradiated enamel indicated that low power laser irradiation produced new calcium phosphate products on the enamel surface, and that low energy CO₂ laser irradiation reduced organisms on the dentin surface.Shika Igaku (J Osaka Odontol Soc) 1997 Mar； 60(1)：45-57．

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Advanced radiographic techniques such as MRI, CT and CR have been developed in recent years, and these techniques have proved useful in producing high-quality diagnostic imaging. Although such techniques produce digital images, the radiographic findings are nonetheless interpreted using analog representations. In spite of the fact that digital analysis is not currently employed, it holds much future promise. Certain types of information such as size, location and extent of invasion are very important, and data regarding these parameters can readily be numerically digitized.
In this study, we chose panoramic radiography as a model in an effort to convert analog findings of lesions to numerical form. We standardized mean values of landmark positions form results of interpretation by a large number of students. And then established a standardized panoramic radiograph based on these values. When any panoramic radiograph is redrawn to this standard, all analytic measurements can be expressed in relative terms and compared to a common standard.
We also studied distortion in panoramic radiographs resulting from positioning errors. Although the quantitative comparison of data of panoramic radiographs from different individuals is difficult, it is now possible using this system. Shika Igaku (J Osaka Odontol Soc) 1997 Mar； 60(1)：58-69．

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The sensitivity of β-lactamase producer Prevotella intermedia (Pi) against β-lactams varies with the type of β-lactam. We studied the substrate profile of β-lactamase extracted from this organism. MIC of penicillins such as PCG, ABPC and MCIPC, and first generation cephems, such as CEX and CEZ, against Pi MA1-V2 was in the range of 25 to 200μg/ml. However, these values for second and the third generation cephems were in the range of 0.2 to 100μg/mg. Pi MA1-V2 β-lactamase hydrolyzed penicillins and first generation cephems except for MCIPC. However, second and the third generation cephems were not hydrolyzed by this β-lactam. These results suggest that Pi MA1-V2 shows high resistance against penicillins and first generation cephems, since it hydrolyzes these drugs with β-lactamase.

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Previous studies have shown that a purified hemagglutinin (25 kDa) from non-fimbriated Prevotella intermeda strain E18 is a protein-polysaccharide complex in nature. We attempted to clarify the relation between hemagglutinin, hemolysin and lecithinase produced by this strain. This 25 kDa protein showed hemolytic activity, but not lecithinase activity. Both hemagglutinating and hemolytic activities of this protein decreased by 50% with heat treatment at 50℃ for 10min, and were lost completely with treatment at 60℃ for 10min. Hemagglutinating activity was gradually lost over time, indicating that the 25 kDa protein contained hemagglutinin, hemolysin and protease.

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In order to study the genetics of methicillin-resistant, coagulase-negative staphylococci (MRCNS), we examined and identified 17 MRCNS strains by DNA-DNA hybridization and by analysis of plasmid and chromosomal DNA. We detected the mec A gene in 16 of the 17 strains. DNA-DNA hybridization identified 60% of the MRCNS strains tested as Staphylococcus epidermidis. All but one strain possessed some plasmid DNA, and each plasmid profile was different. Chromosomal DNA analysis by pulsed-field gel electrophoresis (PFGE) indicated that all of the strains could be classified as one of 13 PFGE patterns. These results indicate that most of the MRCNS strains isolated from MRSA screening agar were mec A gene-positive, and possessed various plasmid DNA and genotypical chromosomal DNA.

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I compared total bacteria, the proportional distribution of Gram-positive bacteria and catalase-positive cocci, and the levels of secretory immunoglobulin A (SlgA) and epidermal growth factor (EGF) in the saliva of patients with aphtha before, after and during use of lactic bacterium beverages. Before using lactic bacterium beverages, all of the aphtha patients had higher levels of bacteria than did the healthy controls. I found that use of lactic bacterium beverages reduced the severity of clinical symptoms in patients with recurrent aphtha. Furthermore, total bacteria and the proportional distribution of Gram-positive bacteria and catalase-positive cocci decreased, while both SlgA and EGF increased. These results indicate that lactic bacterium beverages may be effective in the treatment of recurrent aphtha.

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We investigated cytokeratin (K) expression in well-differentiated human gingival (GK-1) and poorly-differentiated rhinopharyngeal (KB-N) cancer xenograft lines in nude mice. GK-1 expressed Ks 1, 5, 6, 8, 10, 11, 14, 18 and 19, and KB-N expressed Ks 5, 6, 7, 8, 10, 13, 14, 17, 18 and 19. Immunoblotting analysis produced expression of various molecular sizes of K 18 in both lines, and of K 19 in GK-1. Immunohistochemical studies indicated that, compared with GK-1, KB-N reacted strongly and widely with anti CK 8, 18 and 19 antibodies. K 8 of GK-1 showed a stronger reaction in the peripheral cells of the cancer nest, while K 19 expression was stronger in large cancer nests. These results suggest that expression of Ks 1, 8, 18 and 19, and chemical changes in K protein have a strong correlation with malignancy in head and neck cancer.

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Using rat tongue carcinoma induced by 4-nitroquinoline 1-oxide (4NQO), I investigated p 53 expression in the epithelium immunohistochemically with Pab 240 anti-p53 monoclonal antibody, and studied the histological changes during the process of carcinogenesis. Pab 240 was used in this experiment because this antibody recognizes only mutant type p53 during immunoprecipitation analysis. p53-positive cells increased in the epithelium with tumor progression, and significant increases were observed during the periods from 0 to 4 weeks and from 8 to 12 weeks after 4NQO administration. Although no histological changes were observed in the earlier period, hyperplasia and dysplasia were observed in the later one. Mutant type p53 was detected by immunoprecipitation at 16 and 20 weeks after administration of 4NQO. These results suggested that p53 observed in the epithelium with no histological changes was wild type, while that in the hyperplasic or dysplasic epithelium was mutant type.

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We carried out clinical, radiographic and histologic investigations on the effect on induction therapy of external radiotherapy combined with chemotherapy using Bleomycin (BLM) or Peplomycin (PEP) for squamous cell carcinoma of the mandibular gingiva. The induction therapy generally included a total radiation dose of 30 Gy given in 15 fractions over three weeks together with either a total BLM dose of 90mg given in 6 fractions. This therapy seemed effective as a preoperative treatment for mandibular gingival carcinoma because it resulted in long-term remission of the tumor in many cases, even when used alone without adjunctive treatment. This effectiveness was confirmed in histological examination on resected tissues.

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We investigated the supply and demand for dental services in Osaka during 1993. The sufficiency rate for dental services was calculated as the amount of treatment supplied divided by the amount of dental disease during one year. The demand for dental treatment was estimated as the amount of dental disease in 1993 from data of seven reports on national surveys of dental diseases between 1957 and 1993. Dental treatment supplied was estimated from dental treatment performed in 1993 from clinical records of 6,000 patients who visited six private dental offices in Osaka. We then statistically analyzed the factors affecting the sufficiency rate for dental services by multiple regression analysis. We found that increases in the number of dental offices increased the sufficiency rate for decayed teeth, but not for missing teeth.

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I attempted to elucidate the effect of basic fibroblast growth factor (bFGF) on the formation of new hard tissue after pulpotomy by examining the localization of bFGF and alkaline phosphatase (ALP) activity, and by studying the formation of hard tissue on the exposed surface of the pulp using laser scanning microscopy (LSM). Immunohistochemical procedures and LSM revealed bFGF three days after pulpotomy, while new hard tissue formation was evident after 14 days. Localization of ALP activity increased gradually from the surface of the lateral canal wall to the exposed surface of the pulp. This suggests that bFGF may facilitate differentiation and growth of pulp cells, and that newly-formed odontoblasts may promote the formation of new hard tissue.

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I used the TMJ viscoelasticity analyzer to investigate the effect of imbalances in occlusal contact in intercuspal position on the viscoelasticity of the TMJ region by measuring the three properties of viscosity, elasticity and mass. I evaluated 10 healthy volunteers and 28 patients with temporomandibular disorders after checking the conditions of their occlusion. I also measured the viscoelasticity in 10 healthy volunteers before and after clenching for one minute on an experimental occlusal appliance. The results suggested that imbalances in occlusion affect the viscoelasticity of the TMJ region.

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I investigated the effect of vertical cuspal interferences on occlusal force using a three-dimensional transducer placed on one of the mandibular first molars. Interferences were created by placing stainless steel foils of 10, 30, 50, 70, 100, 200, 500, 1,000 or 2,000μm on the flat occlusal table of the transducer. Interferences of between 10 and 100μm caused an increase in occlusal force owing to localization of force in that region. However, EMG activity remaind unchanged. Between 100 and 200μm there were marked changes in occlusal force, EMG activity and mandibular position. There was a decrease in occlusal force in two of three subjects, and an increase in the third.

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I investigated methods of creating traction on a unilateral condyle using three different biteplates, i.e., a bilateral biteplate on the molars, a unilateral biteplate on the molars, and a unilateral pivot. In addition, three different patterns of mandibular displacement were imparted, i.e., voluntary clenching, manual unilateral elevation of the mandible, and unilateral and bilateral myo-monitor pulse stimulation (myo-pulsing). Displacement of the condyle was measured with a computerized axiograph. When used for involuntary mandibular displacement, myo-pulsing with the pivot or the unilateral molar biteplate was the most effective for inferior traction for the contralateral condyle without creating pressure of the condyle against the glenoid fossa. Inferior traction of the condyle did not arise during voluntary clenching with the pivot or either of the biteplates. It appeared that voluntary clenching caused the condyle to press superior and against the glenoid fossa.

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We examined electromyograms (EMG) of the masticatory muscles during unilateral gum chewing and tapping on the mandibular incisors using a Mandibular Kinesiograph on three subjects whose posterior occlusion was altered on one side. All three had full crowns on <567>^^^- on one side. Tests were carried out as each crown was removed in sequence starting from the distal. Loss of support at 7^^^- or <67>^^^- did not significantly change the EMG. However loss of <567>^^^- significantly shifted the tapping points to the deficient side and scattered them. In addition, this significantly increased the coefficient of variation in many of the EMG parameters. These results suggest that loss of unilateral posterior support adversely affects masticatory function.

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We recorded electromyograms at the superior and inferior heads of the lateral pterygoid muscles, anterior belly of the digastric muscle, temporal muscle, masseter muscle and sternocleidomastoid muscle together with incisal movements in 8 normal controls and 9 patients with their mandibles in closed lock. In normal subjects, the superior head showed powerful activity during intercuspal, posterior and ipsilateral clenching, and displayed reciprocal activity with the inferior head during tapping, protrusion and lateral excusion. Decreased activity of the superior and inferior heads were observed in patiets with closed lock. The superior and inferior heads of many of the patients displayed an incoordinated pattern during various jaw movements. These results suggest that electromyographic examination of the lateral pterygoid muscle in various jaw positions may be useful in the diagnosis and prognosis of disc displacement.

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