I investigated the effects of a bite jumping appliance (BJA) on growing Macaca irus monkeys. The sample consisted of three monkeys, one of which was a control. After 32 weeks of active treatment and 24 weeks of retention, I sacrificed the animals and prepared them for histological observation. Plaster models showed that the laboratory animals both had a full Class III relation in the buccal segments, while the control remained in Class I. The Class III relation persisted during the post treatment period.
Cephalometric analysis in the laboratory animals showed that the mandible grew downward and forward, although the maxilla grew little. The maxillary anterior teeth migrated slightly downward and forward during active treatment. Histological findings showed that growth of the post-glenoid spine was altered in the laboratory animals. These results suggest that the BJA is effective for treatment of skeletal Class II malocclusion. Shika Igaku (J Osaka Odontol Soc) 1996 Mar; 59 (1): 1-14.

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I investigated histochemical changes in the masticatory muscles and morphological changes in the cranium induced by elevating the vertical dimension of occlusion in growing rats. One hundred and forty-four 4-week-old male Wistar rats were divided into three groups. In the experimental group, the vertical dimension of occlusion was elevated bilaterally 1.0 mm or 1.5 mm at the maxillary molars. The animals were observed at 5, 7, 10, 13 and 16 weeks of age. I weighed the temporal and masseter muscles from the left side. I then classified the muscles from the right side as type 1, 2A or 2B fibers based on ATPase staining, measured the fiber diameters, and calculated the percentage of each fiber type. I also measured the craniums on cephalograms.
Weights of the masticatory muscles and the mean diameter of the type 2B fibers had decreased at 7 weeks in the experimental animals, and the percentage of 2B fibers in these muscles had increased. The height of the mandibular angle region had significantly decreased at 7and 10 weeks.
These results suggest that elevating the vertical dimension of occlusion retards growth of the masticatory muscles and cranium, and that these changes might be related to a decrease in the diameter of, and an increase in the percentage of, type 2B fibers. Shika Igaku (J Osaka Odontol Soc) 1996 Mar; 59(1): 15-31.

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We investigated morphological changes in the dental arch and skull, and histological changes in the sutures of the nasomaxillary complex after removal of retention following rapid palatal expansion. Morphological analysis based on model measurements, frontal and lateral head x-rays, and occlusal radiography revealed that relapse occurred even in animals retained for 6 months, and that the incidence of relapse of the nasomaxillary complex increased as the retention period became shorter. Relapse occurred more frequently in the posterior region of the dental arch than in the anterior. After three months of retention, normal histological features were observed except in the frontomaxillary and frontozygomatic sutures, where there were extensive connective tissue fibers. Shika Igaku (J Osaka Odontol Soc)1996 Mar; 59(1): 32-42.

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We conducted an experiment using 10 adult male cats in the experiment to elucidate the reasons for changes in gingival blood flow on the side of teeth under pressure from orthodontic force. Forces of 50, 100, 200, 300 and 500 g were applied consecutively to the distal of the maxillary right canines of the anesthetized animals, and changes in the gingival blood flow were evaluated by a laser Doppler flowmeter. We reduced the mesial of the maxillary right canine that pressed directly against the gingiva when force was applied. The same force as before was again applied to the maxillary right canine and gingival blood flow was measured on the pressure side of the gingiva. When the mesial of the tooth was not reduced, an increase in force caused a decrease in gingival blood flow. However, when it was reduced, increasing forces caused virtually no change in the gingival blood flow. We concluded that most changes in gingival blood flow are induced by direct pressure from the tooth on the gingiva. Shika Igaku (J Osaka Odontol Soc) 1996 Mar; 59(1): 43-52.

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We measured the vertical force transmitted through a palatal bar to the maxillary first molars during swallowing in 22 subjects with normal occlusion and mean age of 22.3 years. An intraoral sensor (cantilever type strain gauge transducer), a direct current amplifier, and a recorder were used for the measurements. The sensor was placed on the left maxillary molar band. The right end of the palatal bar was attached to the right maxillary molar band and the left end was connected to the sensor. A Goshgarian type palatal bar was used.
The measurements produced biphasic wave forms. Mean vertical forces were 743.3 g for 5 ml of water, 816.0 g for saliva and 925.2 g for 180 ml of water. Mean durations of applied force were 1.30 sec for 5 ml of water, 1.63 sec for saliva, and 10.37 sec for 180 ml of water. Mean integrals of force over time were 396.2 g・sec for 5 ml of water, 628.2 g・sec for saliva and 2,792.4 g・sec for 180 ml of water.
These results suggest that the palatal bar effectively controls vertical forces on the maxillary molars during orthodontic treatment. Shika Igaku (J Osaka Odontol Soc) 1996 Mar; 59 (1): 53-63.

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We used strain gauges on a dried adult human skull to measure the effect of headgears on the force system of multi-bracket appliances. Extraoral anchorage is often used as an auxiliary to multi-bracket appliances which are employed extensively in orthodontic treatment. This type of anchorage is used to reinforce intraoral anchorage and create forces that supplement the intraoral force system.
An edgewise appliance, which is often used clinically, was fitted to a skull. A force system simlar to that used clinically was reproduced by application of extraoral force to the dental arches of the skull using a facebow headgear or a J-hook headgear.
When the straight-pull type of facebow headgear was used, we noted distal movement (accompanied by lateral expansion) of the maxillary arch as well as a distribution of strain that would tend to elongate the anterior portion of the maxillary arch. When a high-pull type of facebow headgear was used, there was less lateral expansion of the maxillary arch than when a straight-pull type was used. We also noted distal movement and the distribution of strain that depressed the anterior portion in the maxillary dental arch when a high-pull type was used. The J-hook headgear produced the greatest compressive strain when force was applied to hooks placed between the maxillary lateral incisors and canines. Expansion of the dental arches was small when J-hook headgears were used.
These results suggest that the headgear is an effective auxiliary to multi-bracket appliances. Shika Igaku (J Osaka Odontol Soc) 1996 Mar; 59(1): 64-74.

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Using adult and child dried human skulls, we investigated the effects of chin caps on the mandible and craniofacial skeletons, including consideration of different directions of traction force imparted by the chin cap. We used strain gauges to measure the strain distribution on the temporal bone and surrounding sutures, and in the maxilla and mandible. Molar open bite was also investigated to assess the effects of the chin cap on the occlusal surfaces. The chin cap affected the craniofacial skeletons and sutures not only through the condyle, but also through the occlusal surfaces of the molars. The direction of traction from the chin cap affected the center of the area that conducts forces to the craniofacial skeletons. The chin cap force extended to the temporal bones and surrounding sutures, and the direction of traction created by the chin cap produced different effects on mandiblar rotation and the temporal bone. Shika Igaku (J Osaka Odontol Soc) 1996 Mar; 59(1): 75-89.

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I examined the influence of the progression of diabetic microangiopathy on tooth extraction wound healing in streptozotocin-induced diabetic rats. Using microvascular corrosion casts (Ohta et al., 1990), I investigated successive changes in histological structures and microvasculature after extraction of the maxillary first molars. Three groups of Wistar rats were used in this study. The controls were not diabetic. Extractions were done on the controls and two other groups 6 and 16 weeks after diabetic induction. Animals in each group were sacrificed at 3, 5, 7 and 14 days after the extractions. One week after the operation, vascularization was proceeding from the cribriform plate of the socket. Newly-formed bone trabeculae spread richly between newly-formed sinusoids. Two weeks after the operation, the bone formation increased in thickness and proceeded toward the socket margin. Six weeks after induction in the experimental group, healing was similar to that of the controls. However, the blood clot was still visible in the center of the socket one week after the operation in the diabetic rats 16 weeks after induction, and vascularization was seen in the shape of a sinusoidal network without any bone trabecular formation. The socket was still not completely filled with newly-formed capillaries at two weeks. Microvascular patterns played an important role in new bone formation and development during extraction wound healing. Vascularization and new bone formation was delayed in the diabetic groups as the microangiopathy advanced. Shika Igaku (J Osaka Odontol Soc) 1996 Mar; 59(1): 90-98.

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We studied the application of three-dimensional CT imaging in oral diagnosis. Helical CT produces volumetric data and three-dimensional imaging that can be reconstructed as needed, thus decreasing exposure dose. This makes it possible to obtain excellent anatomic detail of facial soft tissues, bone and teeth, and to observe three-dimensional imaging from various directions. It is also possible to accurately measure the dimensions of the subject. We concluded that three-dimensional CT imaging is useful for diagnosis of the maxillofacial region, and that computer graphics is a promising tool for use in dental treatment planning.

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We isolated a hemagglutinin from Prevotella nigrescens strain E4 by mechanical shearing, ultrasonication and gel filtration. Hemagglutinating activity was eltuted in the second peak on a Sepharose CL-4 B column. The activity was sensitive to trypsin, chymotrypsin, protease, β-glucosidase and various detergents, but resistant to heat at 80℃ for 10 min. Addition of _L-lysine and _L-arginine caused hemagglutination inhibition, although addition of _L-fucose, _L-rhamnose and maltose increased the activity. The active fraction reacted with antiserum against hemagglutinin from Prevotella intermedia E 18. These results indicate that this hemagglutinin is a protein-polysaccharide complex and is distributed on most of the cell surface of Prevotella intermedia and Prevotella nigrescens.

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We examined and characterized β-hemolytic activity in Prevotella intermedia and Prevotella nigrescens. More than 94% of the strains tested exhibited hemolytic activity on horse blood agar, while 100% of Prevotella intermedia and 80% of Prevotella nigrescens strains showed a positive reaction on human blood agar. Hemolytic activity of the test strains increased with increases in cell concentration. Long incubation of the bacterial cells produced strong activity. This activity was decreased by lysozyme. These results collectively suggest that hemolytic factors exist throughout the cell surface of Prevotella intermedia and Prevotella nigrescens strains, indicating that both species may aggregate with erythrocytes in vivo, hemolyze, and utilize hemoglobin for their growth.

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This experiment was enforced to apply calcium phosphate cements in endodontic clinics. pH change and apical canal sealing ability of cements were measured. A surface and a internal structure of the cements were observed using SEM. In the pulp tissue and periapical tissue of rats, reactions for the cements were examined histopathologically. As the results, it was found that the cements showed superior physical property. The cement composed of a equimolar mixture of tetracalcium and dicalcium phosphates kneaded with a buffer solution containing diluted citric acid (TeDCPD) induced deposition of hard tissue at the canal wall and closed the apical foramen. The cements which was kneaded with the solution contained high concentration of citric acid induced less or little of hard tissue deposition.

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The shear bond strength (SBS) of silver palladium alloys (Au-Pd) luted with four adhesive resin cements (ARC) and two resin-reinforced glass ionomer cements (RRG) was measured at a temperature and humidity simulating the oral environment. Bonding procedures were done in a constant temperature and humidity device at 32 and 92% relative humidity (C-TH), and at room temperature (RT). As a control, Au-Pd was luted as cast. In the four experimental groups, the Au-Pd was luted after sand-blasting only, after priming only with a primer for precious metals, after sand-blasting and priming, and after tin plating. SBS and the mode of fracture varied with the cement and the method of priming the alloy. The SBS obtained for ARC and RRG at C-TH was significantly different from that obtained at RT, which indicates that temperature and humidity should be taken into consideration during bonding procedures.

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Removal of direct temporary restorations is often complicated when the hardened resin locks into small undercuts. We felt that resin with a low modulus of elasticity during the early setting period could more easily be removed from the prepared tooth. We evaluated the effects of a dibutyl phthalate plasticizer on setting properties of a resin composed of an ethylene glycol dimethacrylate monomer and a polyethyl methacrylate polymer. Strength of the temporary resin restorative material was inadequate when it contained more than 30% plasticizer. However, at 20% the plasticizer adequately prolonged the period where the resin had a modulus of elasticity low enough to allow easy removal of the temporary restoration.

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We conducted a laboratory study on the effect of various dentin conditioners and on the long-term durability of dentin bonding systems. We used the OCPC method to investigate demineralization of bovine dentin by 6 dentin conditioners (10%, 40% and 65% H_3PO_4, 10% citric acid, Imperva Primer^【○!R】 and XR-Primer^【○!R】. We also measured tensile bond strength of resin composite using 5 commercial bonding systems (Superbond D Liner^【○!R】, Clearfil Linerbond^【○!R】, Imperva Bond^【○!R】, XR-Bond^【○!R】 and Tokuso Light Bond^【○!R】). We found that demineralization of dentin with dentin conditioners is necessary for good bonding, although excessive demineralization leads to degradation of long-term bonding durability.

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We inverstigated the influence of axial forces on occlusal contact by measuring the contact area of 7 volunters. A variety of forces, maximum clenching for 1 minute and medium clenching for 1 and 5 minutes were applied to the mandibular first molars as the axial force. With maximum clenching for 1 minute and medium clenching for 5 minutes, the occlusal contact area decreased significantly after application of the force. However, there was no change in occlusal contact area with medium clenching for 1 minute. These findings suggest that occlusal forces are very important when doing occlusal examination.

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We investigated fluoride reaction products occurring on the surface of tooth enamel using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (ESCA). Enamel specimens 3 mm in diameter were prepared from extracted, caries-free human incisors. The surface of the enamel specimens was polished by standard methods and then treated with an acid phosphate fluoride solution (APF ; 9,000 ppm F, pH 3.4). After fluoride treatment, the surface was washed with 1 M KOH and distilled water. Although a large amount of globular materials was observed in the AFM images of the surface treated with APF, this material was eliminated by the KOH wash. Elimination of this material permitted detection of apatite crystals on the surface in the AFM images. Although ESCA analysis of the F and Ca spectra of the APF-treated enamel surface indicated the presence of calcium fluoride, both spectra ware altered after the KOH wash. In particular, the KOH wash shifted the peak position of the F spectrum to the low energy side. These results indicated that the materials produced by APF treatment were calcium fluoride in nature. After the materials were dissolved with KOH wash, fluorapatite might have formed on the enamel surface.

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We investigated how different solutions and antibacterial agents affect the zeta potential of mutans streptococci. The zeta potential was related to serotype, growth rate and incubation time, and was affected by ion strength, pH and the presence of multivalent cations in the solutions. Furthermore, addition of NaF and chlorhexidine significantly decreased the zeta potential of mutans streptococci with larger negative zeta potentials. We concluded that the repulsive force due to surface potential energy between bacterium and hydroxyapatite was increased by lower ion strength, higher pH, and the absence of multivalent cations in the solutions.

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In order to elucidate the localization of glycoconjugate of cells in the reduced enamel epithelium and its derived cells, I did light and electron microscopoic investigations of lectin binging patterns on the reaction of Ulex europaeus agglutinin (UEA-I), peanut agglutinin (PNA), soybean agglutinin (SBA) and wheat germ agglutinin (WGA) with glycoconjugates of cell membranes in rat molars. SBA and WGA reacted with all the cells. UEA-I was reactive with cells of the stratum intermediate and stellate reticulum, but unreactive with ameloblasts, outer enamel epithelium cells, and junctional epithelium cells. The reaction patterns of PNA in these cells differed from those of UEA-I. This sugests that inner and outer cells of the reduced enamel epithelium are heterogenous in their lectin binding patterns.

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