The aim of this study was to compare the gingival surface anesthetic effect of Nd: YAG, Er: YAG laser irradiation and a surface anesthetic using Visual Analogue Scale (VAS) in a short time interval.
Ten adult volunteers participated in this study. The subjects were divided into 3 groups (Nd: YAG laser, Er: YAG laser, control). The irradiated sites were gingival and buccal areas of mandibular incisors. Each laser was irradiated for 1 minite, 3 times at 1.5W. A surface anesthetic was used for the control group. The change of VAS and the depth pierced by a cartridge needle were measured immediately after the laser irradiation, and at the following 1, 2, 3, 4, and 5 minutes. For the control group, these measurements were performed from 3 minutes after the laser irradiation with the same interval. The results were subjected to the Kruskal-Wallis test and Mann-Whitney test.
The results of this study indicated that the VAS value of the Er: YAG laser group was significantly higher than that of the Nd: YAG laser group and control group at immediately after the laser irradiation and was significantly higher than that of the Nd: YAG laser group at 2, 4, 5 minutes after the laser irradiation. However, there was no significant difference between the three groups in the measurement of pierced depth.
This study suggested that Nd: YAG laser is almost equal to a surface anesthetic and that Er: YAG laser is not so effective as Nd: YAG and a surface anesthetic.

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Three types of laser: the Nd: YAG laser, CO₂ laser and Er: YAG laser, have been used for various dental treatments since July 1996 in Comprehensive Dentistry, Niigata Hospital, The Nippon Dental University. In this study, the frequency of using each laser was examined for each category of dental diseases between July 1996 to June 2004. They were used in a total of 1, 158 cases, with a mean age of 49.5 years (range 12 to 81 years). The frequency of use of the Nd: YAG laser (Pulse Master 600 LE, Denics International), CO₂ laser (Opelaser 03S, Yoshida Dental Mfg. Co.), CO₂ laser (Opelaser 03S II SP, Yoshida Dental Mfg. Co.) and Er: YAG laser (Erwin, Morita Co.) were 605 cases (52.2%), 301 cases (26.0%), 249 cases (21.5%) and 3 cases (0.3%), respectively. Based on the results of this survey, various factors such as wavelength characteristics, specifications of equipment, the light guide system and operative ability had significant influences on the selection of laser equipment for each clinical treatment. It is important for effective and safe use of lasers in dental treatment to understand the characteristics of each type of laser equipment.

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The aim of this study was to evaluate histologically the anti-inflammatory reaction following Nd: YAG laser irradi ation in surgical mandibular defects of rats.
Fifteen rats were used in this study and the experimental period was one, three, or seven days. The rats were given a general anaethetic, and the mandibule was exposed using a skin-mucosal flap. In each animal, a surgical defect of 2×2 mm was created at the inferior border of the mandible bilaterally. In the experimental group (Exp), Nd: YAG laser was irradiated to the bone defect and the inside of the skin-mucosal flap under saline water (3.0 W, 30 seconds, 3 times). In the control group (Cont), no intervention was made following surgery. At day 1, 3 and 7, each group of 5 animals was sacrificed. Undecalcified sections were made, stained with tolidine blue, then subjected to histological analysis and planimetric measure ments.
Histological observation revealed that the tissue component inside surgically created bone defects was fibrous connective tissue that was dense and almost regularly aligned in Exp, but the fibrous connective tissue was dense and irregularly aligned in Cont. In Exp, the connective tissue corresponding to the line considered both bone edges (irradiated skin-mucosal flap) was dense and irregularly aligned at day 1, but it was loose and almost regularly aligned at day 7. In Cont, it was loose and regularly aligned at day 1, but was dense and irregularly aligned at day 7. In Exp, the bone edges were observed to be convexo concave and a densely stained area but were not osteoclast and resorption cavity observed during the experimental period. However, in Cont, they were not observed to be convexo concave and densely stained area.
The results of planimetric measurements indicated that there was no statistically significant difference in the areas of surgi cally created bone defects in both Exp and Cont (p>0.05). In addition, there was no statistically significant difference in the number of inflammatory cells in both Exp and Cont during the experimental period (p>0.05).
This study suggested that the anti-inflammatory effect following Nd: YAG laser irradiation is not a quantitative change of the number of inflammatory cells but a qualitative change associated with a histological change caused by laser irradiation.

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この研究の目的は，Nd:YAGレーザーの照射を併用したフラップ手術における術後の臨床パラメーターの変化を検索することにより,術後の歯周組織の治癒についてを臨床的に評価することである。
今回の研究は10名52歯を対象とした。フラップ手術は通法に従って歯肉弁翻転後,ルートプレーニングおよび骨欠損の掻爬を行った。実験群は10名26歯でNd:YAG レーザーを歯根面,骨欠損内部,歯肉弁内面におのおの3.0w，30秒，3回照射した。さらに,術直後に歯肉歯槽粘膜境周囲に対し，1.5w，1分，3回照射した。対照群は10名26歯でレーザー照射を行わなかった。
臨床パラメーターは，Probing depth (PD)，Plaque index (PLI)， Gingival index (GI)， Bleeding on probing (B.O.P)とした。さらに臨床的およびレントゲン的観察を行った。臨床的パラメーターと臨床的およびレントゲン的観察は術前,術後3ヶ月,術後6ヶ月で行い,臨床パラメーターはWilcoxon signed-ranks testによる統計学的分析を行った。
統計学的分析の結果,術後において実験群と対照群の間に各臨床的パラメーターの統計学的有意差を認めなかった。さらに歯肉や骨の壊死,および骨吸収などの臨床的異常所見は認めなかった。
今回の研究はNd:YAGレーザー照射を伴うフラップ手術は,歯周組織に対して臨床的に為害作用がなく安全であり,なおかつ歯肉の炎症の改善が可能であることが示された。

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この研究の目的は，同一患者におけるフラップ手術でのNd : YAG レーザー照射，Er : YAGレーザー照射，消炎鎮痛剤の内服での術後疼痛緩和効果をVASにて比較することである。
今回の研究は11名90歯を対象とした。この研究は3群を設定した。実験群1(11名33歯)は，Nd : YAG レーザーを歯根面，骨欠損内部,歯肉弁内面におのおの3.0W，30秒，3回照射した。実験群2(11名29歯)は，Er : YAG レーザーを歯根面,骨欠損内部，歯肉弁内面におのおの1.0W，30秒，3回照射した。さらに，実験群1および2は術直後に1.5W，1分，3回歯肉頬移行部に照射した。対照群(11名28歯)にはレーザー照射をおこなわず，術直後に消炎鎮痛剤を内服させた。VAS は術直後から6時間後まで1時間ごとに，2日目は起床後から6時間後までとした。
統計学的分析の結果，術後1時間において実験群1が対照群と比較して有意(p＜0.05)に高値であったが，これ以外に統計学的有意差は認められなかった。
今回の研究の範囲内では，フラップ手術におけるNd : YAGレーザー照射，Er : YAGレーザー照射，および消炎鎮痛剤の内服での術後疼痛緩和効果はほぼ同等であることが示唆された。

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この研究の目的は，同一患者のフラップ手術でのNd: YAGレーザー照射と消炎鎮痛剤の内服による術後疼痛緩和効果をVisual Analogue Scale (VAS) にて比較することである。
今回の研究は10名58歯を対象とした。通法に従って歯肉弁翻転後，ルートプレーニングおよび骨欠損の掻爬を行った。実験群は10名34歯でNd: YAGレーザーを歯根面，骨欠損内部，歯肉弁内面におのおの3.0 w，30秒，3回照射した。さらに，術直後に1.5 w，1分，3回照射した。対照群は10名24歯でレーザー照射を行わず，術後に消炎鎮痛剤を内服させた。VASは2日間記録し，1日目は術直後から6時間後まで1時間ごとに，2日目は起床後から6時間後までとした。
計学的分析の結果，術後3時間から4時間後のVASは実験群で有意に高値 (p<0.05) であったが，起床後では統計学的有意差は認められなかった。
今回の研究では，フラップ手術でのNd: YAGレーザー照射は消炎鎮痛剤の内服での術後疼痛緩和効果とほぼ同等であることが示唆された。

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