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Successor
Volume 44 (2000)
- Issue 6 Pages 725-
- Issue 5 Pages 625-
- Issue 4 Pages 479-
- Issue 3 Pages 371-
- Issue 2 Pages 179-
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Predecessor
Volume 44, Issue 5
Displaying 1-11 of 11 articles from this issue
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Kazumasa Kato, Shoji Kohno, Eiko Arai, Toyohiko Hayashi, Yoshiaki Yama ...2000 Volume 44 Issue 5 Pages 625-632
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSThe purpose of this clinical study was to show that videofluorography (VF) is a useful tool for diagnosis of mastication and swallowing. A series of modifications of a VF system allowed a relaxed posture for the patient and easy orientation of the patient's head under the condition of low-level X-ray exposure. Visual analyses using this system were effective, especially in denture prosthetic treatment, as follows:
1. The habitual retracted tongue position during mastication was a cause of lower complete denture instability.
2. A palatal reshaping prosthesis improved the disphagia that bothered a patient after partial excision of the tongue and mandible due to oral floor cancer.
3. Distal extention of the denture base to the space left after a segmental mandible resection could improve mastication and swallowing.
4. The potential risk of aspiration pneumonia in an elderly patient who had a cerebral infarction history and who wore new complete dentures.
5. A patient's strong demand to masticate food by himself after total glossectomy and mandibulectomy was satisfied by a prosthesis as a substitute for the tongue and teeth.
The results suggested that VF imaging analysis was available to evaluate masticatory function in denture wearers.View full abstractDownload PDF (4844K) -
Yuichi Shigeoka, Makoto Shiota, Hidekazu Takahashi, Fumio Nishimura2000 Volume 44 Issue 5 Pages 633-642
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSThe purpose of this study was to investigate the accuracy of working casts fabricated by a transfer system. A master model was fabricated from a single standing ITI implant with a solid abutment. Working casts were fabricated from two methods.(One was a stone-model using the conventional method, and the other was a transfer-model using the transfer system with an impression cap and a shoulder analog.) A profile projector was used to measure the dimensional changes of dies. The conclusions were as follows:
1. Regarding the dimensional change of dies on transfer-models, the width of the joint part and the height of the shoulder were as accurate as those on stone-models; however, the width of the abutment was slightly small, and the height of the abutment was slightly large.
2. The distortion of reference points on stone-models had a tendency toward upper and outside. On transfer models, reference points of the upper part of the abutment had a similar tendency, however; those of the joint part and the shoulder edge distorted toward lower.
3. The distortion of the center point on stone-models had a tendency toward upper; however, that on transfer-models scarcely distorted.
4. On both models, there was little inclination change in the long axis.View full abstractDownload PDF (3678K) -
Jiro Kishii, Mutsuo Yamauchi, Makoto Sakai, Takashi Omiya, Takehiro Is ...2000 Volume 44 Issue 5 Pages 643-650
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSIn this study, we investigated if electrolyzed water (strong acid electrolyzed water and strong alkaline electrolyzed water) could be applied to plaque control of resilient denture liners.
Five commercially available resilient denture liners were immersed in electrolyzed water or distilled water for two weeks. Rubber hardness, surface roughness, color, and weight were measured before immersion and at 1 and 2 weeks after immersion.
The strong acid electrolyzed water changed the rubber-hardness-acrylic-type and fluorine-type resilient denture liners color of acrylic type and polyorefine type resilient denture liners, compared with distilled water. However, surface roughness and weight of these resilient denture liners were not affected by immersion in the electrolyzed water. Other resilient denture liners were not affected by immersion into the electrolyzed water, for all experimental items.
These results suggest that there were few effects on the property of resilient denture liners, and that electrolyzed water can be applied for cleaning of resilient denture liners.View full abstractDownload PDF (1401K) -
Antimicrobial Action for Streptococcus mutansTakaaki Tanaka, Kazuhiro Mizukawa, Kouichirou Shida, Taira Kobayashi, ...2000 Volume 44 Issue 5 Pages 651-657
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSRecently, the concept of hygiene has been promoted, and many sanitary goods that contain antimicrobial reagents have been produced. Such reagents are divided into organic and inorganic ones. Some literature has pointed out that these reagents have many disadvantages, such as short-time durability of antibacterial effect, degeneration by heating operation, and physical irritation. Furthermore, the organic antimicrobial reagents have intensive antimicrobial action, but long use of these reagents may cause microbial substitution and teratogenicity.
We aimed to put inorganic antimicrobial reagent into practical use, and the effects of silver-inorganic antimicrobial reagents (IONPURETM and NOVARON AG 300TM) on oral microorganisms were examined.
1. Minimum inhibitory concentrations (MICs) of antimicrobial reagents (IONPURE and NOVARON) for Streptococcus mutans were 7.5 mg/m/ and 1.3 mg/m/. The antimicrobial action was bacteriostatic. The microorganisms on resin plates that contained both antimicrobial reagents were remarkably reduced.
2. MICs for Streptococcus mutans on resin plates that contained antimicrobial reagents were 5 wt%(IONPURE) and 10 wt%(NOVARON).
3. Insoluble glucan synthesis was inhibited on NOVARON-containing resin plates. On the other hand, IONPURE was not so noticeable.
4. The surviving microorganisms of Streptococcus mutans on resin plates that contained both antimicrobial reagents (3 wt%) were remarkably decreased.
These results suggest that IONPURE and NOVARON were effectual antimicrobial reagents against Streptococcus mutans, and that they were useful for antimicrobial prosthesis.View full abstractDownload PDF (1407K) -
Nagakazu Ko, Rieko Ko, Tsunetoshi Shimazu, Takao Maruyama2000 Volume 44 Issue 5 Pages 658-662
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSObjects: The aim of this study was to investigate the role of dental metals in the development of atopic dermatitis (AD).
Subjects and method: From 300 patients with refractory AD, who showed positive lymphocyte stimulation test (LST) reactions to dental metal salts, we removed the dental restorations that contained LSTpositive metals and evaluated the improvement of clinical symptoms.
Result: Positive LST reactions were observed in 98% to Hg, 95% to Ni, 37% to Au, 27% to Ag, 31% to Pd, and 24% to In, respectively. The ratio of clinical symptom improvement “excellent” and “good” was 70%(211/300).
Conclusion: Clinically recalcitrant lesions were improved by dental metal removal. This fact reveals that dental metals play an important role in the pathogenesis of refractory AD.View full abstractDownload PDF (995K) -
Hiroyasu Koizumi2000 Volume 44 Issue 5 Pages 663-674
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSThis study investigated the effect of toothbrush abrasion in all-ceramic restoration at the margin. Specimens were made of human enamel, all-ceramic (IPS Empress, IVOCLAR), and resin cement (Variolink II, VIVADENT). Sectional profile, vertical wear, and surface roughness of the luting cement were measured by a scanning laser microscope. The width of luting cement was determined to be 50, 100, 150, and 200μm. Then, the wear surface and the margin were observed on scanning electron micrographs.
Sectional profiles showed a saw-toothed line at the worn surface of luting cement. Margins of human enamel and all-ceramic were eliminated by a toothbrush, and slopes like a bevel edge were observed. There was a significant difference (t-test) between wear depth of the luting cement and the thickness of the cement line. Vertical wear of the luting cement was larger, and the cement line was thicker at the end of the toothbrush abrasion test. On the other hand, the surface roughness of luting cement was increased in all specimens.View full abstractDownload PDF (3428K) -
Fumiaki Kawano, Takafumi Ohguri, Kenji Oka, Tetsuo Ichikawa, Naoyuki M ...2000 Volume 44 Issue 5 Pages 675-682
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSHigh-abrasion-resistance-resin teeth are widely used to make removable dentures, instead of porcelain teeth and resin teeth, because of the high fracture toughness, high abrasion resistance, and so on. Shock absorbability is an important property of artificial teeth, because the impact force of th occlusal contacts is transmitted directly to supporting structure under a denture. The purpose of this study was to evaluate the shock absorbability of commercially available posterior teeth by a free drop-ball test with an accelerometer. The results were as follows:
1. The maximum acceleration of porcelain teeth is greater than that of resin teeth and high-abrasionresistance teeth. High-abrasion teeth showed intermediate maximum acceleration between resin teeth and porcelain teeth.
2. Porcelain teeth showed the shortest duration of maximum acceleration in the artificial teeth investigated. All of the high-abrasion-resistance teeth showed an intermediate duration of maximum acceleration between resin teeth and porcelain teeth. There was no significant difference among the high-abrasion teeth.
3. Resin teeth showed excellent resistance impact force. The impact force of high-abrasionresistance teeth was intermediate between that of porcelain teeth and resin teeth.
The results show that high-abrasion-resistance teeth have high shock absorbability compared with porcelain teeth.View full abstractDownload PDF (2901K) -
Part 3. Influence of Investment MaterialAkio Asano, Mutsuo Yamauchi, Makoto Sakai, Motonobu Miyao, Tooru Nagas ...2000 Volume 44 Issue 5 Pages 683-689
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSA cast-soldering method is used for the keepers of magnetic attachments. However, there have been few studies concerning the effects of the cast-soldering method on keepers. In this study, the cast-soldering method was investigated by changing the cast investment material.
Two commercially available keepers and a 12% Au-Ag-Pd alloy were used. Two conventional, and one quick-heating-types of gypsum-bonded investment were used. Cast-soldering was performed at a mold temperature of 700°C for 30 minutes using a vacuum-pressure-type casting machine. After cast-soldering, the interface between the keeper and the casting alloy was observed by metallic microscopy and scanning electron microscopy. The interface was also analyzed with an X-ray electron microprobe.
A black layer (consisting of a reaction layer and a gap) was observed between keeper and Au-Ag-Pd alloy. The black layer was smallest with the conventional gypsum-bonded investment (cristobalite type), compared with the other. When using the quick-heating-type of gypsum-bonded, and gypsum-bonded (cristobalite and quartz type), investment, the black layer was equal to or larger than that when using the conventional type of gypsum-bonded investment (cristobalite type).
The finding suggests that the conventional gypsum-bonded investment (cristobalite type) is preferred for the cast-soldering method of keepers.View full abstractDownload PDF (2988K) -
Kazuyoshi Hashimoto, Kazumichi Yamamoto, Takashi Yokoyama, Kiyokata Su ...2000 Volume 44 Issue 5 Pages 690-695
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSIn principle, a stabilization-splint covers the entire dental arch, and the occlusal contact should be equally distributed around the arch, but in our clinic, we sometimes make solid posterior contact at the specific area by adding self-curing resin on the occlusal surface of the splint. Since a stabilization splint that covers the entire dental arch is comparatively large, it is not easy to make equally distributed occlusal contact due to inaccurate impression, polymerization shrinkage, and technical errors on occlusal adjustment.
It seems that the condyle motion in wearing an occlusal splint is a factor that infers the prognosis of temporomandibular disorders, but it is not entirely clear. When the splint does not have equally distributed occlusal contact, the temporomandibular joint may possibly have an excess load. To solve this problem, our experiment was conducted to study the displacement of the mandibular condyle during clenching, with a stabilization splint and with a device whose occlusal surface was modified.
The results of the experiment were the following: When the subject clenched on the right first molar with the stabilization splint, with a 1.0-mm-thick pivot by adding self-cure resin on the occlusal surface at this area, the right mandibular condyle significantly moved latero-inferiorly. When the subject clenched on the right second molar with the stabilization splint, with a 0.5-mm-thick pivot, the right mandibular condyle significantly moved antero-superiorly. There was no significant difference except for the above two conditions.View full abstractDownload PDF (2090K) -
Tsuguyoshi Kohno, Shoji Kohno2000 Volume 44 Issue 5 Pages 696-708
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSWe have previously demonstrated that, during jaw open-close movements, there is a functionalrhythmical coupling between the head and the mandible, and that the head undergoes a rotation-like movement whose center of rotation (CR) is located inside the head. We believe that such concomitant motion occurs to balance the head during jaw movement. This study was made to confirm this theory, and to verify the CR's location and functional purpose. The same 6-degree-of-freedom motion measuring device and analyzing method from our prior studies was used in 11 healthy subjects, but in some of them, a controlled external force was applied to the head during jaw movements, to induce resistance and changes in head motion. In the subjects without loads, there was a high incidence of concomitant head and jaw movements. This was in contrast to the subjects with loads applied, i.e., the incidence decreased, but the CR kept the location inside the head. Yet, the vertical location of the CR relative to the cervical spine was similar in all subjects. We concluded that concomitant head and jaw movement is influenced by the vertical shift of the CR, and that it serves to balance the head in relation to the body.View full abstractDownload PDF (2894K) -
Akinobu Furuya2000 Volume 44 Issue 5 Pages 709-710
Published: October 10, 2000
Released on J-STAGE: August 10, 2010
JOURNAL FREE ACCESSDownload PDF (841K)
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