Tomohisa Watanabe

Aichi Gakuin University, Nagoya, Aichi, Japan

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Publications (3)6.05 Total impact

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    ABSTRACT: Abstract Objective: The purpose of this in vivo study was to examine morphologic alterations in the periodontal pocket epithelium with presence or absence of clinical inflammation following the use of the Neodymium: Yttrium-Aluminum-Garnet (Nd:YAG) laser irradiation. Background data: Subgingival Nd:YAG laser irradiation has been proposed as an alternative technique for treatment of chronic periodontitis. Several published studies have reported the clinical outcomes of such treatment. Methods: Twenty patients, diagnosed with moderate chronic periodontitis, were selected for the study. A total of 32 sites was identified and divided into a control (n=18) and laser-treated test groups (n=14). Probing depth (PD) and bleeding on probing (BOP) were recorded for all sites. Test sites were irradiated with an Nd:YAG laser using parameters of 2 W, 200 mJ pulse energy, and 10 pps delivered through a 320 μm diameter tip. Total laser treatment time ranged from 1 to 2 min. Following treatment, all specimens were harvested via biopsy and processed for scanning electron microscopy (SEM) and histologic examination. Results: Control group specimens, depending upon initial PD, exhibited either a relatively smooth and intact epithelium with little desquamation (PD ≤3 mm), or increasing degrees of epithelial desquamation and leukocytic infiltration at a PD of ≥4 mm. In the laser-treated test group, the specimens with PD ≤3 mm that were BOP negative (-) exhibited a thin layer of epithelium that was disrupted. In the specimens with initial PD of ≥4 mm, complete removal of the epithelium whose extent and degree were increasing, was observed in the inflamed portion, while epithelium remained in the uninflamed portion. Conclusions: The SEM and histologic findings demonstrated the feasibility of ablating pocket epithelium with an Nd:YAG laser irradiation using parameters of 2 W of power (200 mJ, 10 pps). Furthermore, the presence or absence of clinical inflammation appeared to have an impact on the degree of laser-mediated epithelial ablation.
    No preview · Article · Sep 2014 · Photomedicine and Laser Surgery
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    ABSTRACT: Abstract Objective: The aim of this study was to investigate the effect of laser irradiation on root surface demineralization caused by local drug delivery systems (DDS), and to evaluate the effect of sealing on drug retention. Background data: The duration of supportive periodontal treatment (SPT) has increased with increasing life expectancy. Repeated root planing and DDS application during SPT should be reconsidered with regard to their effects on the root surface. Methods: Extracted human teeth were collected, cut into 3×3×2 mm root dentin specimens, and divided randomly into eight groups with various combinations of Nd:YAG laser power (0, 0.5, 1, and 2 W), with and without DDS (minocycline HCl). Specimen microhardness and calcium (Ca) solubility were measured after treatment. The specimens (control and laser and DDS groups) were examined by scanning electron microscopy. Forty SPT patients were recruited, to assess the effect of periodontal pocket sealing on drug retention. Results: Laser irradiation increased the microhardness of root specimens in an energy-dependent manner. Calcium solubilities decreased from the 0 W+DDS group to the 2.0 W+DDS group. The mean Ca solubilities in the 1.0 W+DDS and 2.0 W+DDS groups were significantly lower than in the 0 W+DDS group (p<0.01, p<0.001, respectively). Laser irradiation counteracted the softening effect of DDS. Morphologic change was observed in the 2W+DDS group; however, no morphologic changes were observed in the control and the 1W+DDS groups. The mean concentration of minocycline in the periodontal pocket 24 h after application was 252.79±67.50 μg/mL.Conclusions: Laser irradiation of the root surface inhibited the softening and decalcification caused by minocycline HCl. Sealing the periodontal pockets effectively improved drug retention. These results suggest that the combination of laser irradiation and DDS could benefit patients receiving repeated SPT.
    No preview · Article · Nov 2013 · Photomedicine and laser surgery
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    ABSTRACT: This in vitro study was performed to determine the appropriate power output setting for an erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser used in periodontal pocket irradiation by examining the morphologic alterations of the root surfaces and the efficiency of calculus removal. Sixty-five non-carious extracted human teeth were used in this study. For morphologic analysis of the root surface, the clean, single roots of 22 teeth were separated into 91 pieces, and these pieces were immersed in acrylic resin. The specimens with root-surface exposure were prepared and divided randomly into three groups: a control group (N=8), an irradiation without water group (no water [NW] group; N=39), and an irradiation in water to simulate the conditions in a periodontal pocket group (in water [IW] group; N=44). The power output settings for laser irradiation were 0.5, 1.0, 1.5, and 2.0 W for each group. The roughness (Ra), depth (Z), and width (X) of the disk specimens were determined after laser irradiation. Eight other single-rooted teeth were examined by scanning electron microscopy (SEM) after laser irradiation under the same conditions. Thirty-five single- or multirooted teeth with heavy subgingival calculus were used to test the efficiency of laser scaling. The efficiency of calculus removal was quantified by measuring the time needed to remove the calculus completely using the laser. The mean Ra and Z values in the IW group were significantly higher than in the NW group with the same power output. In addition, these values with 0.5- and 1.0-W power output settings were significantly lower than with 1.5- and 2.0-W settings in the NW and IW groups. No obvious morphologic differences could be found between the 0.5- and 1.0-W power output specimens under SEM. Additionally, thermal alterations, i.e., carbonization or melting, were completely absent in the IW group. Regarding the efficiency of calculus removal, the 0.5-W setting (0.11+/-0.036 mm2/second) was significantly inferior to the 1.0-W setting (0.27+/-0.043 mm2/second). However, there was no significant difference between 1.0- and 1.5-W (0.36+/-0.11 mm2/second). The 2.0-W setting (0.63+/-0.272 mm2/second) was much more efficient but resulted in significant morphologic alterations. Based on these findings, it is appropriate to use a 1.0-W power output setting with an Er,Cr:YSGG laser for root scaling. This may be done without any conspicuous morphologic alterations to the root surface and with acceptably efficient removal of calculus.
    No preview · Article · Dec 2007 · Journal of Periodontology