Hiroshi Kato

Hokkaido University, Sapporo, Hokkaidō, Japan

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Publications (5)2.16 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of this study was to compare an ultrasonic furcation tip with an ultrasonic conventional tip and a hand scaler on accessibility to furcation areas of mandibular first and second molars. The study was conducted on 360 artificial molars that were replicated from 30 mandibular first molars and 30 second molars with silicone impression material and resin. The furcation areas of each molar were coated with red nail colour for artificial calculus. The root areas from the cement-enamel junction apically were covered with silicone rubber simulating gingival tissue. Then the models were instrumented on the buccal or lingual aspects by an experienced operator with each of the following instruments: an ultrasonic furcation tip, an ultrasonic conventional tip and a hand scaler. After instrumentation the percentage of the furcation area with residual artificial calculus was assessed using a computerised imaging system. Results showed that when the horizontal pocket depth was less than 2mm, all three instruments showed good accessibility. When the horizontal pocket depth was more than 2mm, the ultrasonic conventional tip and the hand scaler showed less removal of artificial calculus than the ultrasonic furcation tip (P < 0.01). Efficiency of the ultrasonic furcation tip was fairly satisfactory for the horizontal pocket up to the ridge of the furcation roof.
    Journal of the International Academy of Periodontology 11/2002; 4(4):132-7.
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    ABSTRACT: The purpose of this study was to evaluate the clinical effects of closed debridement with an ultrasonic furcation tip in degree II furcation involvement of mandibular molars. Fifteen patients with degree II furcation involvement in mandibular first and/ or second molars participated in the study. All patients were given oral hygiene instruction. Plaque score, probing depth, probing attachment level and bleeding on probing were recorded at baseline, 1, 4, 8 and 12 weeks. Following a baseline examination, a single episode of supra- and subgingival debridement was provided using an ultrasonic furcation tip in the test group, and an ultrasonic conventional tip and hand scalers under local anesthesia in the control group. At baseline, the mean horizontal probing depth in the test group was 6.35 mm and in the control group 6.06 mm. These values decreased to 4.88 mm and 5.29 mm respectively after 12 weeks. There were horizontal probing attachment gains of 1.29 mm in the test group and 0.59 mm in the control group after 12 weeks (P < 0.01). The bleeding scores were 1.0 in the test group and 0.88 in control group at baseline. These scores were improved to 0.12 in the test group and 0.59 in the control group after 12 weeks (P < 0.01). The results suggest that ultrasonic debridement with a furcation tip has a significantly better potential in treating degree II furcation involvement of mandibular molars.
    Journal of the International Academy of Periodontology 11/2002; 4(4):138-42.
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    ABSTRACT: The purpose of this study was to evaluate whether hard tissue might be formed on dentin surfaces applied with recombinant human bone morphogenetic protein-2 (rhBMP-2) in palatal connective tissue. Fifty-eight dentin blocks were prepared from rat roots, demineralized with 24% EDTA (pH 7.0), applied with 0, 50 and 100 microgram/ml rhBMP-2, and labeled as groups 0, 50 and 100. The dentin blocks were then transplanted into palatal connective tissue of rats, and specimens were prepared at two and four weeks after surgery for histologic and histomorphometric examinations. The results showed that the percentage of newly formed hard tissue in relation to the total dentin block surface length in groups 0, 50 and 100 was 0.0%, 2.8% and 4.4% at two weeks, and 0.0%, 1.6% and 12.8% at four weeks, respectively. New hard tissue formation in groups 50 and 100 was significantly promoted as compared to group 0 (p < 0.01). These findings thus indicate that rhBMP-2 application to dentin enhanced new hard tissue formation on dentin surfaces in the connective tissue of the palate.
    Journal of Periodontal Research 06/2002; 37(3):204-9. · 1.99 Impact Factor
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    ABSTRACT: The purposes of this study were to develop and verify the a portable nocturnal bruxism monitoring and analysis device equipped with a microcomputer, and to clinically apply the device to know the actual conditions of bruxism patients. EEPROM was installed in the device for the data recording, and after the data collection, the recorded data was entered into a personal computer via serial port. After confirming the accuracy of the device, a total of 30 subjects were enrolled in this study to monitor their bruxism activities for 3 nights. Bruxism self-aware group consisted of 14 subjects, 7 males and 7 females, and unaware group consisted of 16 patients, 8 males and 8 females. Most of the subjects reported that the new device was easy to handle. The average bruxism time per hour and the average bruxism lasting time were 223.8 +/- 112.0 and 3.9 +/- 2.9 s in the self-aware group, and 49.3 +/- 38.3 and 0.8 +/- 0.7 s in the unaware group, respectively. The bruxism self-aware group showed statistically longer average bruxism time per hour and the average bruxism lasting time. It was confirmed that the new bruxism monitoring and analysis device is practical for clinical application to monitor and analyze the electromyographic activities.
    Frontiers of Medical & Biological Engineering 02/2002; 11(4):295-306.
  • Ryuji Sakagami, Hiroshi Kato
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    ABSTRACT: The purposes of this study were to evaluate the geometric and densitometric reproducibility of a newly developed standardized X-ray system and to examine the radiographic changes after scaling/root planing as shown by this device. The system was comprised of three parts: an acrylic bite piece for the individual patient, an aluminum wedge-equipped holder, and a holder-connecting device. The experiment was performed at 32 sites of premolar and molar areas in 19 patients. Radiographs were retaken 6 weeks after scaling/root planing and the reproducibility and radiographic changes were examined. The vertical and horizontal geometric reproducibility of the system at 32 sites in 19 patients were 1.0% and 1.8%, respectively. Of 351 scaled sites, 39 (11.1%) exhibited bone regeneration, and 6 (1.7%) exhibited bone loss. These results indicate that the newly developed system has high accuracy and clinical usefulness. Early bone remodeling can be observed radiographically after 6 weeks with our standardized X-ray system.
    Oral Radiology 05/2000; 16(1):1-7. · 0.17 Impact Factor