DNA-DNA hybridization in stock cultures of B. intermedius and lactose fermenting black-pigmented Bacteroides resembling B. intermedius isolated from periodontal pockets, periapical lesions and saliva was studied by the photobiotin method. Some of these bacterial strains showed phenotypic characteristics which included producing lecithinase on egg-yolk agar plate, yielding viscous material in Todd Hewitt broth, and producing β-lactamase.
Dot hybridization studies indicated that all of the clinical isolates formed homogenous groups, as is the case with the four ATCC strains of B. intermedius. These isolates were distinct from other ATCC strains of black-pigmented Bacteroides.
These results indicated that all the clinical isolates tested were B. intermedius. Quantitative hybridization of clinical isolates with the labeled ATCC type strain and ATCC 33563 revealed two homology groups, the ATCC 25611 and ATCC 33563 groups. Clinical isolates of the ATCC 25611 group predominated in adult oral infections. The ATCC 33563 group predominated in children's saliva.
Phenotypic characteristics useful in differentiating between ATCC 25611 and 33563 were not observed. However, strains in the ATCC 25611 and 33563 group produced different polyacrylamide gel electrophoretic patterns. Therefore, these two homology groups will be reclassified as different species of Bacteroides in the future, as was pointed out by Johnson & Holdeman.

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We characterized partially purified fimbriae from B. intermedius strain 17. Activity of the fimbriae was monitored by hemagglutination with rabbit erythrocytes. Lowering the pH of the fimbriae solution caused precipitation. Absorbance at 280nm of the supernatant reached a minimum at pH 4.5, suggesting that this was the isoelectric point. This pH value coincides with minimum hemagglutination activity. When the fimbriae solution was dialyzed against buffer at pH 4.0 or less, hemagglutination activity was reduced or lost. Fifty percent of hemagglutination activity was inhibited by heat treatment at 60-70℃ C for 10 minutes, and 94% at 100℃ for 10 minutes. The proteolytic enzymes trypsin, protease type IV and proteinase partially destroyed the hemagglutination activity. These results indicate that fimbriae are essentially proteinaceous in nature. Addition of D-glucosamine caused hemagglutination inhibition, suggesting that D-glucosamine may be associated with receptors for fimbriae.

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We identified black-pigmented Bacteroides (BPB) species isolated from periodontal pockets in advancing periodontitis and examined the antimicrobial susceptibility of these organisms. Of 121 strains of BPB tested, 46 were identified as B. intermedius, 76 were B. gingivalis, and three were B. endodontalis. Three strains of B. endodontalis were identified by DNA-DNA hybridization. PCG, ABPC, AMPC, CET, CPZ, DOXY, MINO, MDM and CLDM were effective against B. gingivalis, while MDM was effective against B. intermedius. B. endodontalis was sensitive to PCG, ABPC, AMPC, CET, CMD, CPZ, LMOX, FLOX, DOXY, MINO, EM, MDM and CLDM. Of 46 strains of B. intermedius, 19〜36% were resistant to penicillins, 5〜26% to cephems, 17% to tetracyclines, and 2〜5% to macrolides. The activity of β-lactamase was detected in one penicillin-resistant strain of B. intermedius. These results suggest that B. intermedius may play an important role in oral infections, including periodontitis.

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A new bonding system has been developed which is comprised of a UDMA base resin METAFIL I and a 4-META methyl methacrylate bonding agent which bonds to dentin. In vitro dentin bonding tests and in vivo pulpal irritation tests were carried out. The dentin bonding tests used human teeth which had been placed in 4℃ physiologic saline solution as soon as possible after extraction and had been stored in this way for several months. Five types of etching agent were used : 20% phosphoric acid (20-P), 25% phosphoric acid (25-P), 40% phosphoric acid gel (40-P), 10% citric acid-3% ferric chloride (10-3) and 0.5M EDTA at pH 7.4. GLUMA (10% glutaraldehyde-35% hydroxy-ethyl-methacrylate) was used as a primer after etching. Clearfil New Bond was used as a bonding agent for comparison with 4-META MMA. Composite resins used were the Clearfil-posterior chemical polimerization type in the case of Clearfil New Bond, and the METAFIL I light curing type in this case of 4-META MMA.
For the pulpal irritation test in vivo, METAFIL I composite resin with 4-META MMA bonding agent was placed in the teeth of Japanese monkeys. At the same time, other materials were also tested using the same monkeys as controls for comparison with the METAFIL I system. The ADA, FDI/ISO diagnosis system was used as a basis for evalvating pulpal irritation.
The following results were obtained :
1) The adhesive strength to dentin of 4-META MMA showed generally the same or slightly higher values compared with Clearfil New Bond.
2) The 10-3 solution and the 40-P gel proved to be the proper etching solutions.
3) The use of GLUMA as a primer had no particular effect.
4) The degree of pulpal irritability was the same or less than the other composite resin restorative materials.
5) There seemed to be no problems with clinical application of this system since the amount of reparative dentin resulting from pulpal irritation was slightly more than the control and no severe harmful effects were observed.

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The palatal bar is used with a headgear in clinical orthodontics to control the vertical growth of the maxilla. We investigated the effects of two types of palatal bar on the facial skeleton by measuring the strain distribution around the maxillary first molars using triaxial rosette gauges set on dry skulls of one adult and one child.
The results obtained were as follows :
1. When the straight palatal bar was used, high compressive strain oriented at right angles to the occlusal plane was found in the buccal segments of the bone surrounding the maxillary first molars. The magnitude of the compressive strain in this region produced by the curved palatal bar was smaller than that by the straight type.
2. When the straight palatal bar was used, the lingual alveolus around the maxillary molars was subjected to high compressive strain oriented at right angles to the occlusal plane. The magnitude of the compressive strain in this region was greater with the curved palatal bar than with the straight type.
3. Both types of palatal bar produced pronounced counterclockwise rotation of the maxilla of the dry skull of the child, similar to that experienced with high-pull headgear traction.
4. Strains were found in the frontal process of the maxilla, nasal bones, infraorbital area of the maxilla, and the areas around the frontonasal and zygomaticomaxillary sutures.
5. The degree of strain on the infraorbital foramen was significant in the dry skull of the child.
Clinically, the palatal bar increases the stability of the maxillary buccal segments, and decreases their normal vertical descent. Reduction of vertical facial growth tends to close the mandibular plane angle and move the relative position of the mandible forward. The results of this experiment suggest that the palatal bar might be useful for anchorage to resist the elongation and mesial migration of the maxillary first molars produced by intermaxillary elastics in adults.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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