I investigated the optimum ultrasonic therapy of the masseter muscle for temporomandibular disorders (TMD). The deep temperatures of the bilateral masseter muscles and the forehead were measured non-invasively at rest and after ultrasonic therapy in 14 normal male subjects. The right masseter muscle of each subject was exposed to a continuous sonic wave of 3 MHz, at an intensity of 0.5, 0.75, and 1.0 W/cm² for 5 and 10 minutes. The subjects were asked about pain during and after the ultrasonic therapy. The deep temperature was calculated at rest, and at 20 and 60 minutes after ultrasonic therapy (ΔT), and the ascending rate (AR) and descending rate (DR) were calculated from the deep temperature under each condition. The ΔT and AR for 10 minutes were significantly higher than for 5 minutes. The DR for 1.0 W/cm² was significantly higher than for 0.5 W/cm^2. No subject experienced pain at the intensity of 0.5 W/cm² during or after ultrasonic therapy. These findings suggest there is an optimum ultrasonic therapy of the masseter muscle for TMD.

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We examined speech intelligibility after glossectomy and analyzed electromyograms (EMG) of myoelectrical activity of the sternocleidomastoid and trapezius muscles at various head positions after radical neck dissection. Speech intelligibility after glossectomy became lower the larger the area of resection. Although articulation was very good in the case of partial glossectomy, it was markedly impaired with hemiglossectomy. However, patients who had reconstruction by a pectoralis major myocutaneous flap operation were able to recover an essentially normal social life. Analysis of electromyograms after radical neck dissection revealed compensatory activities in the middle part of the sternocleidomastoid muscle with ventral flexion, and in the trapezius muscle on the side of the operation with ipsilateral tilting.

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Although glycosaminoglycans (GAG) clearly play an important role in wound healing, there have been few reports on changes in GAG during osseous healing around titanium implants. We investigated histochemically and immunohistochemically the location of GAG around implants using 15-week-old Sprague-Dawley rats. Titanium implants 1.0 mm in diameter and 3.0 mm long were inserted into the thighbones. The animals were sacrficed 1, 2, 3, 5 and 10 weeks after the operation. Deparaffinized sections were histochemically stained with toluidine blue after hyaluronidase digestion. Other deparaffinized sections were treated with 2 B 6 (for chondroitin 4 sulfate), 6 B 6 (for dermatan sulfate) antibodies, and stained by the indirect immunoperoxdase technique. Hyaluronic acid was identified on tissues around the implant at 1 week. Chondoitin sulfate and calcification were identified after 2 weeks in the peri-implant tissue. After 3 weeks, dermatan sulfate was identified in the peri-implant tissue, and calcification had become active. There was strong reaction for GAG in the first and third weeks. These results indicate that large amounts of GAG were produced within the first three weeks after the implant operation, and that there was a close connection between calcification and osseous healing around the implant.

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Using cats anesthetized with urethane and chloralose, we studied the effect of conditioning stimulation applied to the fornix (Fx) on the response of nociceptive neurons in the intralaminar nuclei and in the nucleus ventralis posteromedialis (VPM). In one third of the intralaminar neurons, conditioning Fx stimulation at an intensity of less than 1mA inhibited responses to peripheral input and/or to electrical stjmulation of the tract. Conditioning stimulation of the Fx did not inhibit the response to electrical stimulation in any of the VPM neurons. The results suggest that nociceptive neurons in the intralaminar nuclei are inhibited following conditioning stimulalion of the Fx. This inhibition arising from the Fx acts mainly at the thalamic level of the medial pain pathway.

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Previous studies have shown that exopolysaccharjde (EPS) from Prevotella intermedia is related to the jnvasjveness of bacteria. In this study, we attempted to purify EPS derived from Prevotella nigrescens and compared it with that from P. intermedia. We also isolated an EPS^- strain from the EPS^+ strain by treatment with ethidium bromide, and examined the pheno- and genotypic characteristics of these strains. Purified EPS was primarily carbohydrate consisting of mannose, glucose, galactose, arabjnose and xylose. However, the ratio of mannose was greater in the EPS from P. nigrescens than in that from P. intermedia. The plasmid bands and enzymatic activities were the same for both EPS^- and EPS^+. The hemagglutinating activity of the EPS^- strain was greater, indicating that EPS tends to interfere with hemagglutination than mediate it.

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Vesnarjnone (3, 4-dihydro-6-[4-3, 4-dimethoxybenzoyl-1-piperazinyl]-2 (1H)-quinolinone) is an jnotropic agent used in treating congestive heart failure. However, its clinical application is limited because it has agranulocytosis as a sideeffect. To clarify the mechanism of vesnarinone-induced agranulocytosis, we investigated the effects of vesnarinone on ceramide-related cell growth, apoptosis and cytokine secretion. In HL-6O cells, vesnarinone increased cell differentiation and apoptosis when assessed by NBT (nitroblue tetrazolium) reducing ability and DAPI staining. It also in-creased generation of ceramide. We also found both vesnarinone and ceramide enhanced TNF α-induced IL-8 secrelion from HL-6O cells, and that ceramjde significantly inhibited TPA-induced IL-6 secretion from HFL-1 cells. These results suggest that vesnarjnone-induced agranulocytosis caused both the inhibition of growth factor secretion from fibroblasts, and the enhancement of cell differentiation and apoptosis via ceramide signalling in hematopoietic cells.

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Occjusal interferences of 1 mm thickness were placed bilaterally on the maxillary second molars of male Wister rat sat 4 weeks of age. The interferences were removed at 7 weeks of age in group A (n=36) and at 11 weeks of age in group B (n=2O). The interferences were left in place in group C (n=43). Group D (n=49) was the control. Angular and linear measurements were made of the cranium and mandible at 7, 11, 13 and 16 weeks of age. Cephalometric analysis indicated that the viscerocranium grew upward and forward in group C, while the mandibular ramus and angle grew posteriorly. In groups A and B, the cranium and mandible tended to recover from the deviated growth after removal of the occlusal interference, however this tendency was more pronouced in group A than ingroup B.

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In order to reserch the role of cytokeratin (CK) 19 gene expression in carcinogenesis, I investigated the effect of the expression of CK 19 gene in oral squamous cell carcinoma, epithelial dysplasia and normal gingiva. Total-RNA was extracted from biopsy materials and examined by revers transcription polymerase chain reaction (RT-PCR) and northern blot. The results showed that CK 19 mRNA expressed in every sample, and it was strongly positive in squamous cell carcinoma, moderately positive in epithelial dysplasia and slightly positive in normal gjngiva. These results jndicafes that CK 19 gene is an important factor of carcinogenesis in oral squamous cell epithelia.

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We evaluated the effect of various periodontal treatments, which included scaling alone, scaling followed by use of YAG and C0_2 lasers, root planing alone and root planing followed by use of YAG and CO_2. lasers. Evaluations were carried out using an X-ray microanalyzer (XMA), by scanning electron microscopy (SEM), by X-ray photoelectron spectroscopy (ESCAP), and by measuring the contact angles in vitro. Comparisons of the irradiation and non-irradiation groups by XMA, GEM, and ESCA indicated little difference whether the irradjation followed scaling or root planing, or whether the YAG or CO_2. lasers were used. However there were differences in the contact angles.

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Periodontitis is the chronic inflammation caused by bacteria in dental plaque. Integrins play an important role in cell adhesion, transmigration and proliferation at the inflammation sites. I developed a new method of cell adhesion assay using non-radioactive, pyrimidine analogue 5-bromo-2'-deoxyuridine (BrdU). Phytohemagglutinin (PHA)-activated T cells were labeled by BrdU and examined for binding to intercellular adhesion molecule-1 (ICAM-1) and extracellular matrix proteins (ECM), such as fibronectin, laminin and collagen. CC-chemokines, such as monocyte chemoattractant protein-1 (MCP-1) and regulated on activation, normal T cell expressed and secreted (RANTES) enhanced adhesion of PHA-T cells to ICAM-1, but not to ECM. Moreover, MCP-1 and RANTES enhanced adhesion of PHA-T cells to the fibroblast-like cell line, E 11 cells in ICAM-1/lymphocyte function associated antigen-1 (LFA-1) dependent fasion.

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Although it is reasonable to believe that alteration of occlusion may cause or exacerbate temporomandibular disorders, the exact role of occlusion is still unknown. I immunohistochemically examined the changes that occurred after tooth extraction in rat mandibular condylar cartilage. Unilateral maxillary molars were extracted from rats, and the temporomandibular joints were resected after 1, 2, 3 or 6 months. The tissues were fixed with paraformaldehyde, embedded in paraffin after decalcification with EDTA, and then prepared in serial sections for immunohistochemjcal examination for types I, II and X collagen, chondroitin 4-sulfate, chondroitin 6-sulfate, keratan sulfate and dermatan sulfate proteoglycan. In the experimental rats, staining for types I and X collagen, C4S, KS and DSPG was stronger, whereas that for C6S was weaker, than in the controls. These findings seem to indicate a loss of elasticity in the mandibular condylar cartilage.

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I developed a questionnaire to select the seven words most important in expressing the properties an operator requires during use of composite resin (CR) restorative materials. The statistical analysis divided the seven words into two factors of rheology and stickiness. One hundred twenty-seven words chosen from a dictionary were included in a questionnaire that was conducted using subjects who chose the appropriate words to express the operator's perceplion during placement of restorations. Thirty-three words were selected. The subjects placed six CR restorations in a cavjty to evaluate their ease of use, and then filled out the questionnaire. Statistical analyses revealed that the operator's perception during handling of the CR was mainly related to rheology and stickiness. I concluded that the appropriate selection of words for the questionnaire was very important in obtaining an objective evaluation of ease of manipulation of CR.

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Because it is difficult to predictably create caries in human teeth, I developed artificial carious dentin (ACD) that has physical properties similar to those of the collagen fibers of natural carjous dentin (CD). It was experjmentajjy developed by treating intact human dentin with 0.1M lactic acid for two hours followed by treatment with typeI collagenase for another two hours. ACD was compared with CD by SEM observation and measurement of the Knoop hardness (KH). SEM observation revealed that the collagen fibers of ACD were narrowed and band fibrils had disappeared, much like CD. KH was comparable for the two. The similarity of ACD and CD suggests that the treatment of natural dentin with 0.1M lactic acid and typeI collagenase produces a useful ACD.

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Titanium (Ti) is very effective as an implant material. I carried out in vitro experiments on the adsorption of salivary proteins and serum proteins to Ti to better understand how this material reacts in the oral cavity. I found that when Ti that had adsorbed serum proteins was exposed to salivary proteins, there was an exchange of the proteins on the Ti surface. The same thing happened when Ti that had adsorbed salivary proteins was exposed to serum proteins. This suggests that both human salivary proteins and serum proteins adsorb to Ti with different affinity, and that protein already adsorbed to Ti might mask binding sites for other proteins.

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I examined how fixation of the soldering investment and heat treatment after welding prevented welding deformation in a three-unit bridge. The experiment was carried out using a specially constructed metal die for welding that provided strong fixation. Deformations induced by soldering and one-piece casting were compared with these induced by laser welding. The best method of predictably obtaining precise dental prostheses was by welding the casting fixed firmly on the metal die and then heat treating it.

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Under varjous conditions, I evaluated masticatory muscle tone by recording vertical dimension and velocity of mandjbular movement with electric stimulation. Ten stimulations were applied with the mandible in the rest position. The descending dimension and maximum velocity of descent were measured. Both parameters were lower in temporomandibular disorder (TMD) patients than in healthy subjects. Both of these values were higher after treatment for TMD than before treatment, and the values after treatment became similar to those in healthy subjects.

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I investigated the relationship between the mandibujar closing velocity and masseter muscle (Mm) activity. Closing was analyzed during three phases (accelerating, rapidly decelerating and slowly decelerating). While the rhythm of opening and closing movements changed, the maximum closing speed, average acceleration and Mm activity increased as the rhythm increased during the accelerating phase. Mm activity during the slowly decelerating phase was significantly less than during the rapidly decelerating phase. The paths of the smoothed raw electromyograms were similar to the mandibular kinesiograph vertical motion velocity curves. These results suggest that Mm activity affects mandibular closing velocity.

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I investigated the optimum ultrasonic therapy of the masseter muscle for temporomandibular disorders. Deep tenperatures of the bilateral masseter muscles and forehead were measured non-invasively at rest and after ultrasonic therapy. The right masseter muscle of each subject was exposed to a continuous sonic wave of 3 MHz, at an intensity of 1.0, 0.75, and 0.5 W/cm^2 for 5 and 10 minutes. The ascending rate for 10 minutes was significantly higher than that for 5 minutes, and the descending rate for 1.0 W/cm^2 was significantly higher than that for 0.5 W/cm^2. These resuits suggest there is an optimum ultrasonic therapy of the masseter muscle for temporomandibular disorders.

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I investigated how different methods of fixing the superstructure over osseointegrated implants influenced the stomatognathic system. Six subjects with IMZ implants and 20 normal subjects were studied. The superstructure on each implant was either an intramobile element, an intramobile connector, or a titanium element. Mechanical mobility of each implant was measured with a tooth nobility tester, and occlusal contacts were determined with the add-picturesystem. Muscle activity of the masseter, anterior temporal and anterior belly of the digastric muscles was evaluated by electromyography. The results suggest that the intramobile mechanism affects mobility, occlusal contact and masticatory function.

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