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 tapping points and the EMG. However loss of 567 significantly shifted the tapping points to the opposite side and scattered them. In addition, this significantly increased the coefficient of variation (CV) in many of the EMG parameters and decreased burst activity. In particular, this significantly increased the CV of burst duration outlasting tooth contact, and decreased burst activity outlasting tooth contact, during gum chewing on the contralateral side. These results suggest that loss of unilateral 567 support adversely affects masticatory function. Shika Igaku (J Osaka Odontol Soc) 1997 Sept； 60(3)：173-183．

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Because it has fine mechanical strength and biocompatibility, cast titanium has recently been used in the fabrication of crowns and bridges. Recent attempts have been made to fuse porcelain to pure titanium to improve its application in esthetic areas. However, when titanium is alloyed with porcelain fusing metals, problems arise with strong oxidation of the metal surface and coarse oxidative adhesion. We compared the marginal distortion of metal copings during the firing cycle of porcelain fused to four different metals: pure titanium, precious alloy, semiprecious alloy and nonprecious alloy, and studied how the oxidation heat temperature affected the bonding strength for clinical applications.
Marginal distortion of the metal frame made of pure titanium was considerably less than that of the other three metals following the degassing the stage, and was relatively small and constant during the firing cycle. Specimens made under oxidation temperatures between 500 to 800°C that were held for three minutes had the highest bond strength and the lowest coefficient of variation with stable strength. Shika Igaku (J Osaka Odontol Soc) 1997 Sept； 60(3)：184-194．

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I investigated the relationship between craniofacial morphology and mandibular movement in 25 subjects with no signs of TMJ dysfunction. I measured craniofacial morphology with antero-posterior and lateral cephalograms. Mandibular movements (incisal and condylar paths) were recorded and calculated by a six-degree of freedom jaw movement analyzer (Gnatho-Hexagraph). The measured values of craniofacial morphology and mandibular movement were compared using coefficients of correlation.
During maximum opening of the mandible, incisal movements correlated with the maxillo-mandibular size. Condylar movements correlated with the relation of anteroposterior position of the maxilla and mandible, and the axial inclination of mandibular incisors. During maximum protrusion of the mandible, incisal movements correlated with maxillary dental height, mandibular size, and the relation of the anteroposterior position of maxilla and mandible. Condylar movements correlated with the FH-Y axis and maxillomandibular width. During lateral movement of the mandible, incisal movements correlated with the interincisal angle and maxillomandibular dental height. Condylar movements correlated with maxillomandibular size and axial inclination of the mandibular incisors.
These results suggest that mandibular movement is a functional movement related to craniofacial morphology. Shika Igaku (J Osaka Odontol Soc) 1997 Sept； 60(3)：195-204．

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I investigated the effect of mandibular lateral deviation and condylar path on mandibular border movement. The subjects included 10 men and 10 women with permanent dentition and no temporomandibular dysfunction. Standard PA radiographs were taken in a cephalostat, and the extent of lateral skeletal deviation was measured. Mandibular border movements were recorded at six degrees of freedom during opening, protrusion, retrusion and lateral excursion with a Gnatho-Hexagraph JM-1000. The measurement point of the condyle was located on the kinematic axis. Condylar movement was evaluated along the 3-D linear path of the condyle, and mandibular rotation was determined at maximum opening and inclination of sagittal condylar path during mandibular protrusive movements.
The correlation between the bilateral difference in the 3-D linear path of the condyle at maximum opening and the lateral skeletal deviation was significantly positive (p<0.05). The condylar path length had a tendency to be longer on the deviation side than on the other side. However the correlation between the bilateral difference in mandibular rotation and the lateral skeletal deviation was significantly negative (p<0.05). The mandibular rotation had a tendency to be smaller on the deviation side than on the other side. No significant differences were detected in the other parameters examined. These results suggest that lateral skeletal deviation affects bicondylar path length. Shika Igaku (J Osaka Odontol Soc) 1997 Sept； 60(3)：205-210．

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Using the T-Scan PC System, I calculated reference values by a parametric statistical method for 11 parameters of occlusal contact during intercuspation. Measurements were made at levels of light clenching (100 newtons or less) at all contact points. The subjects were 59 males and 50 females between the ages of 20 and 30 years, all of whom had healthy temporomandibular function. Six occlusal time reference values were measured: total front back (TFB), primary front back (PFB), left front back (LFB), right front back (RFB), total left right (TLR) and primary left right (PLR). Five occlusal force parameters were also measured: left force (LF), right force (RF), left right moment (LRM), left lever (LL) and right lever (RL). Using this data, I was able to determine reference intervals for the 11 parameters from the T-Scan System during time and force occlusal examination in intercuspal position for temporomandibular joint dysfunction. Shika Igaku (J Osaka Odontol Soc) 1997 Sept； 60(3)：211-220．

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I studied the OFLX resistant mechanisms of anaerobic Gram-negative bacilli originating from odontogenic infections because new quinolone resistant bacteria are being isolated from these infections treated with ofloxacin (OFLX). The bacterial strains used were Prevotella buccae (P. buccae) ATCC 33574 (OFLX susceptible strain), P. buccae 31-8 (low level OFLX resistant strain, isolated from a closed dentoalveolar abscess), and P. buccae 31-8-R4 and 31-8-R5 (high level OFLX resistant strains), both selected from P. buccae 31-8 using OFLX.
The DNAs of the two high level resistant strains were highly hybridized with that of the parent strain. Enzymatic productivity was confirmed between the parent strain and the high level resistant strains. The MICs of six new quinolones (OFLX, levofloxacin, sparfloxacin, lomefloxacin, tosufloxacin and norfloxacin) were 1-8 μg/ml for P. buccae ATCC 33574, 0.5-16 μg/ml for P. buccae 31-8, 16-64 μg/ml for P. buccae 31-8-R4, and 16〜＞128 μg/ml for P. buccae 31-8-R5, respectively, using agar dilution at 10⁶ CFU/ml of inoculum. The growth of OFLX resistant strains was suppressed with OFLX (1/32-1/2 MIC) and 2.5μg/ml carbonyl cyanide m-chlorophenylhydrazon (CCCP). Furthermore, the growth suppression of OFLX resistant strains was observed among the other five new quinolones (1/8 MIC) and 2.5 μg/ml CCCP. Accumulation of OFLX was not detected in OFLX susceptible P. buccae ATCC 33574 cells with 2.5 μg/ml CCCP. However, this accumulation was recognized in low and high level OFLX resistant P. buccae 31-8-R4 and 31-8-R5 cells. The value of these accumulations with CCCP increased by 1.07 to 1.24 times in comparison to that without CCCP. The 75.8 kDa outer membrane protein detected from the OFLX susceptible strain was not detected in the SDS-PAGE pattern from low and high level OFLX resistant strains. Also, 29.4 and 63.2 kDa outer membrane proteins appeared in the OFLX resistant strains, and the bands of 35.2 and 47.3 kDa from the outer membrane proteins in OFLX resistant strains were wider than those from the susceptible strain.
These results suggest the possibility that the efflux of new quinolone and the obstruction of outer membrane permeability are related to the OFLX resistant mechanism of P. buccae. Shika Igaku (J Osaka Odontol Soc) 1997 Sept； 60(3)：221-231．

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We did an in vivo study with weekly observations of the relationship between toothbrush bristle wear and brushing force with the rolling method, as well as an in vitro study of the relationship between bristle wear and the removal of experimental plaque. The in vivo study indicated that the subjects tended to increase brushing force as the bristles became worn. The in vitro study indicated that the hardness of the bristles decreased with use. The actual area cleansed decreased over the life of the toothbrush for all values of brushing force. These results indicate that tooth-brushes should be replaced every 4 weeks for maximum plaque removal effect.

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We examined the localization of some cytokine receptors and their downstream intracellular signaling molecules in the trigeminal ganglia (TG) of rats. Among cytokine receptor components, we examined the signal transduction sub-chains, gp 130, IL-2 Rγ and IL-5 Rβ, which are common to cytokine receptors. Most of the sensory ganglion neurons expressed gp 130, but not IL-2 Rγ or IL-5 Rβ. We further examined the localization of Janus kinase (JAK) family members which were reported to be associated with various types of cytokine receptors and are thought to be implicated in major cytokine receptor signaling pathways. Furthermore, activated JAKs phosphorylate receptors as well as cytoplasmic proteins belonging to a family of transcription factors called the signal transducers and activators of transcription (STAT) , providing a novel signaling pathway that is shared by all members of the cytokine receptor. We also examined the expression of STAT 3 in the TG. We showed that gp 130, JAK 1, JAK 2, Tyk 2 and STAT 3 are expressed in small neurons which are known to be related to nociception and associated with IL-6, CNTF, OSM and LIF signaling.

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In order to study the cause of temporomandibular joint disorder (TMD), I investigated the contribution of temporomandibular joint (TMJ) morphology to the development of TMD in a retrospective study of MR images of TMD patients and individuals free of clinical TMD symptonls. I examined retrospectively the axial MR images of 397 patients with clinical diagnosis of TMD, using 550 individuals without clinical TMD symptoms as controls. The distance between the bilateral mandibular heads, and the horizontal angulation of the mandibular heads was measured for each subject. The average horizontal angulation of the mandibular heads in the TMD group was 20.1° in males and 18.4° in females, while these values in the control group were 18.2° and 19.3°, respectively. The average distance between the bilateral mandibular heads was 102.8 mm in males and 97.4 mm in females for the TMD group, compared with 106.6 mm and 101.8 mm, respectively for the controls. There was no statistical correlation between the horizontal angulation and the distance between the bilateral heads at any age. However, there was a statistical difference of 100 mm in males and 95 mm in females for the distance between the bilateral heads for in the TMD group and the controls. These results indicate that this factor may be useful in discriminating between normal individuals and TMD patients. They further suggest that a narrow distance between the mandibular heads rather than their horizontal angulation may contribute to the etiology of temporomandibular joint disease.

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I investigated how TMJ loading affects sounds of TMJ movement by recording sounds at two measurement sites for four different mandibular positions and three different jaw opening speeds. Recordings made 20 mm anterior to the average condylar position clearly caught the changing conditions of the TMJ. Observing changes in frequency components was informative. It was desirable for the jaw opening speed to be slow or moderate. Loading the front of the TMJ increased the high frequency component of the sounds generated by TMJ movement. One method for diagnosing mild cases of TMD might be to observe the range of frequencies between those of normal and abnormal subjects.

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I used a rat model to study a technique for constructing prefabricated vascularized bone grafts using vascularized periosteum, atelocollagen and bone marrow. The animals were divided into 2 groups: one with vascularized periosteal grafts combined with an atelocollagen, and the other with a composite of atelocollagen and bone marrow. Grafts in the controls were prepared only with periosteum. Histological and radiographic observations were made between 3 days and 9 weeks. Active bone formation occurred in all animals during the 2 weeks following surgery. Grafts in the two experimental groups produced a greater amount of new bone than they did in the controls for the period between 5 and 9 weeks after surgery. It was concluded that atelocollagen may serve as an effective carrier of vascularized periosteum.

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