Pub Date : 1900-01-01DOI: 10.5984/JJPNSOCLASERDENT.23.86
K. Takamori, D. Nasu, T. Shinoki, T. Shirakawa
The Er:YAG laser is useful in endodontic treatment compared with conventional methods, resulting in disinfection of the root canal and elimination of smear layers including bacteria and debris. An irradiation tip for root canal treatment has been developed; it can be used to perform lateral ablation using 20% power in the forward direction and 80% power in the lateral direction. However, the relationship between energy loss and distance of the endodontic irradiation tip was unclear. The aim of this study was to evaluate irradiation energy loss with change in distance, using an Er:YAG laser apparatus (Erwin AdvErL, J. Morita, Kyoto) and irradiation tip (R200T, J. Morita, Kyoto). The laser sensor (LMP10LP, COHERENT Inc., Portland) was placed vertically or horizontally at the irradiation tip. The irradiation energy was measured three times using a laser power meter (Field Master-GS, COHERENT Inc., Portland). The distance between the irradiation tip and sensor was varied from 1.0 to 10.0 mm. Irradiation energy was found to be inversely proportional to distance. An energy change was not clearly observed with low energy irradiation (30 mJ), however, a high energy (50 mJ and 70 mJ) setting has decrease of energy for influence distance. The lateral position was more greatly affected by the change in distance than the vertical position. These results suggested that the energy of the new irradiation tip varied in both the vertical and horizontal directions. (J. Jpn. Soc. Laser Dent. 23:86 ~ 89, 2012 Reprint requests to Dr. TAKAMORI) Key words= Er:YAG laser, Root canal irradiation tip, Energy alteration, Distance キーワード= Er:YAGレーザー,根管照射用チップ,出力変化,距離
{"title":"Basic Study of the Relationship between Root Canal Irradiation Tip Distance and Irradiation Energy","authors":"K. Takamori, D. Nasu, T. Shinoki, T. Shirakawa","doi":"10.5984/JJPNSOCLASERDENT.23.86","DOIUrl":"https://doi.org/10.5984/JJPNSOCLASERDENT.23.86","url":null,"abstract":"The Er:YAG laser is useful in endodontic treatment compared with conventional methods, resulting in disinfection of the root canal and elimination of smear layers including bacteria and debris. An irradiation tip for root canal treatment has been developed; it can be used to perform lateral ablation using 20% power in the forward direction and 80% power in the lateral direction. However, the relationship between energy loss and distance of the endodontic irradiation tip was unclear. The aim of this study was to evaluate irradiation energy loss with change in distance, using an Er:YAG laser apparatus (Erwin AdvErL, J. Morita, Kyoto) and irradiation tip (R200T, J. Morita, Kyoto). The laser sensor (LMP10LP, COHERENT Inc., Portland) was placed vertically or horizontally at the irradiation tip. The irradiation energy was measured three times using a laser power meter (Field Master-GS, COHERENT Inc., Portland). The distance between the irradiation tip and sensor was varied from 1.0 to 10.0 mm. Irradiation energy was found to be inversely proportional to distance. An energy change was not clearly observed with low energy irradiation (30 mJ), however, a high energy (50 mJ and 70 mJ) setting has decrease of energy for influence distance. The lateral position was more greatly affected by the change in distance than the vertical position. These results suggested that the energy of the new irradiation tip varied in both the vertical and horizontal directions. (J. Jpn. Soc. Laser Dent. 23:86 ~ 89, 2012 Reprint requests to Dr. TAKAMORI) Key words= Er:YAG laser, Root canal irradiation tip, Energy alteration, Distance キーワード= Er:YAGレーザー,根管照射用チップ,出力変化,距離","PeriodicalId":187459,"journal":{"name":"Journal of Japanese Society for Laser Dentistry","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128627869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.5984/JJPNSOCLASERDENT.24.72
Naoya Yoshihashi, E. Murakashi, Hiroko Takeuchi-Igarashi, Y. Numabe
{"title":"The Effect of Nd:YAG Laser Irradiation on Human Gingival Fibroblasts","authors":"Naoya Yoshihashi, E. Murakashi, Hiroko Takeuchi-Igarashi, Y. Numabe","doi":"10.5984/JJPNSOCLASERDENT.24.72","DOIUrl":"https://doi.org/10.5984/JJPNSOCLASERDENT.24.72","url":null,"abstract":"","PeriodicalId":187459,"journal":{"name":"Journal of Japanese Society for Laser Dentistry","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126894220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.5984/JJPNSOCLASERDENT.5.73
F. Sugata, K. Ohmori, Teruo Tanaka, T. Yuuzu, A. Senda, A. Gomi, K. Kamiya, J. Hasegawa
The purpose of this study was to examine the morphlogical changes and the thermal effects of the CO2 laser irradiation on dentin. For this study, eighteen extracted hu man molars were used. In the experiment examining morphological changes, the irradiation power was 1 to 10 watts, the pulse times were 10 to 500ms and the irradiation frequency was 1 to 20 times. On the dentin surface irradiated by CO2 laser under various conditions, the carbonized area became wider, if the irradiation energy increased.But the depth and width of the cavity was the same, when the irradiation power was con stant. the irradiation energy densities were less than 153J/cm2, the dentin surface changed without making any cracking.In the experiment examining thermal effects, dentin blocks, 1.0 and 2.0mm in thickness, of extracted molars were prepared. These were lased by the CO2 laser using 1 to 5 watts at 10ms pulse mode for 30 seconds.The thermal increase transmitted from the lased surface was measured with the thermoco uple. The results indicate that the thermal increase depends on the dentin thickness and is in inversely proportional to the square of the dentin thickness. For example the thermal in crease should not rise more than 5 degrees for 10 seconds, when the dentin thickness is more than 2mm and the irradiated power is less then 2 watts. This result suggests that this laser irradiation may be successfully used in clinical situation as one of dentin treatment tech niques after further clarification of thermal effects on dental pulp.
{"title":"The Effect of CO2 Laser Irradiation on Dentin","authors":"F. Sugata, K. Ohmori, Teruo Tanaka, T. Yuuzu, A. Senda, A. Gomi, K. Kamiya, J. Hasegawa","doi":"10.5984/JJPNSOCLASERDENT.5.73","DOIUrl":"https://doi.org/10.5984/JJPNSOCLASERDENT.5.73","url":null,"abstract":"The purpose of this study was to examine the morphlogical changes and the thermal effects of the CO2 laser irradiation on dentin. For this study, eighteen extracted hu man molars were used. In the experiment examining morphological changes, the irradiation power was 1 to 10 watts, the pulse times were 10 to 500ms and the irradiation frequency was 1 to 20 times. On the dentin surface irradiated by CO2 laser under various conditions, the carbonized area became wider, if the irradiation energy increased.But the depth and width of the cavity was the same, when the irradiation power was con stant. the irradiation energy densities were less than 153J/cm2, the dentin surface changed without making any cracking.In the experiment examining thermal effects, dentin blocks, 1.0 and 2.0mm in thickness, of extracted molars were prepared. These were lased by the CO2 laser using 1 to 5 watts at 10ms pulse mode for 30 seconds.The thermal increase transmitted from the lased surface was measured with the thermoco uple. The results indicate that the thermal increase depends on the dentin thickness and is in inversely proportional to the square of the dentin thickness. For example the thermal in crease should not rise more than 5 degrees for 10 seconds, when the dentin thickness is more than 2mm and the irradiated power is less then 2 watts. This result suggests that this laser irradiation may be successfully used in clinical situation as one of dentin treatment tech niques after further clarification of thermal effects on dental pulp.","PeriodicalId":187459,"journal":{"name":"Journal of Japanese Society for Laser Dentistry","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122252854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.5984/jjpnsoclaserdent.3.45
Y. Tani, T. Nambu, C. Watanabe
Soldering has been chiefly used for jointing prosthetic materials. Titanium is very difficult to solder because it is highly susceptible to oxidation. The recent development of an infrared heater soldering system is expected to make titanium soldering easier. However, because this soldering system uses a solder different from the conventional solder, it may cause problems in the oral cavity such as low resistance to corrosion. Titanium soldering requires prior fixation with the investment material. Therefore, the authors recently attempted laser welding of titanium.In this attempt, normal pulse Nd-YAG laser (ML-2310A, Miyachi Technos Co.) was used. Laser welding was first used to join 2 titanium cast crowns together and then 2 round tita nium rods (2mm in diameter) together under the following settings: voltage, 300V; pulse width, 6ms (for crowns) or 5ms (for round rods); output, 7J (for crowns) or 6J (for rods). The round rods were rotated during welding. The focus spot diameter was 0.6mm. Laser was applied to the materials while spraying argon gas onto them.In both cases, laser welding resulted in glossy and strong union. Because the spot diameter was small, the heat-affected area was very narrow. Therefore, direct welding on a working model was possible, without necessitating fixation with an investment material. In case of round rods, it was possible to hold one end of both rods between fingers during laser welding. Because laser welding is a kind of sweating, it is expected to involve no risk for reduction of anti-corrosion resistance inthe welded area.The weld strengths of titanium plate specimens obtained by two different welding techniques were compared. With a laser beam (70mm in focal distance, 0.8mm in diameter), two titanium plates (40×10×3mm), superimposed each other 2mm at the end, were welded either by lap seam welding or by spot welding. The load required to tear off the joint by pulling for the spot-welded specimen was 56kgf in average, while that for the lap-seam-welded specimen was more than 106kgf in average, where the breakage of the base metal often arose in the proximity of the weld.A major factor hampering the utilization of titanium for prosthesis is the difficutly in processing. If laser welding is introduced to titanium, the dental application of titanium will widen.
{"title":"Welding of Titanium using Normal Pulse Nd-YAG Laser","authors":"Y. Tani, T. Nambu, C. Watanabe","doi":"10.5984/jjpnsoclaserdent.3.45","DOIUrl":"https://doi.org/10.5984/jjpnsoclaserdent.3.45","url":null,"abstract":"Soldering has been chiefly used for jointing prosthetic materials. Titanium is very difficult to solder because it is highly susceptible to oxidation. The recent development of an infrared heater soldering system is expected to make titanium soldering easier. However, because this soldering system uses a solder different from the conventional solder, it may cause problems in the oral cavity such as low resistance to corrosion. Titanium soldering requires prior fixation with the investment material. Therefore, the authors recently attempted laser welding of titanium.In this attempt, normal pulse Nd-YAG laser (ML-2310A, Miyachi Technos Co.) was used. Laser welding was first used to join 2 titanium cast crowns together and then 2 round tita nium rods (2mm in diameter) together under the following settings: voltage, 300V; pulse width, 6ms (for crowns) or 5ms (for round rods); output, 7J (for crowns) or 6J (for rods). The round rods were rotated during welding. The focus spot diameter was 0.6mm. Laser was applied to the materials while spraying argon gas onto them.In both cases, laser welding resulted in glossy and strong union. Because the spot diameter was small, the heat-affected area was very narrow. Therefore, direct welding on a working model was possible, without necessitating fixation with an investment material. In case of round rods, it was possible to hold one end of both rods between fingers during laser welding. Because laser welding is a kind of sweating, it is expected to involve no risk for reduction of anti-corrosion resistance inthe welded area.The weld strengths of titanium plate specimens obtained by two different welding techniques were compared. With a laser beam (70mm in focal distance, 0.8mm in diameter), two titanium plates (40×10×3mm), superimposed each other 2mm at the end, were welded either by lap seam welding or by spot welding. The load required to tear off the joint by pulling for the spot-welded specimen was 56kgf in average, while that for the lap-seam-welded specimen was more than 106kgf in average, where the breakage of the base metal often arose in the proximity of the weld.A major factor hampering the utilization of titanium for prosthesis is the difficutly in processing. If laser welding is introduced to titanium, the dental application of titanium will widen.","PeriodicalId":187459,"journal":{"name":"Journal of Japanese Society for Laser Dentistry","volume":"171 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121071826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.5984/JJPNSOCLASERDENT.8.7
Koichi Matsumoto, F. Suwa, H. Ike, Y. Murata, R. Shirasu, M. Kumazaki
The purpose of this study was to examine the depth into penetration of the tissue and the circulatory structure of the microvasculature after irradiation the Nd: YAG laser on the lingual dorsum of a 9-week-old male wistar rat.The Nd: YAG laser was irradiated against the tongue of rats under the following condition; the energy level; 1, 2 and 3-Watts for 1.0, 2.0 and 3.0 seconds.Wounds of tongue were observed macroscopically, microscopically and also examined by SEM. The following results were obtained; Microscopical findings: The penetration was observed until the lamina propria in 1W1S and 1W2S groupsThe penetration of 1W3S, 2W2S and 3W1S groups were observed still superior tranversus linguae layer and also were observed in the muscle layer for 3 second group.SEM findings: The capillary loops of the papillae and the lamina propria venure networks were damaged in 1W1S and 1W2S groups.Irradiation wounds disappeared in the capillary loops of the papillae and the lamina propria venure networks.In 1W3S, 2W2S and 3W1S groups, and also disappeared in the capillaries of muscle layer in 3 second groups.(J. Jpn. Soc. Laser Dent. 8: 7-15, 1997 Reprints request to Dr. MATSUMOTO)
{"title":"Exchange of Nd: YAG Laser Irradiation and Damage of Microvascularization on the Rats Lingual Dorsum","authors":"Koichi Matsumoto, F. Suwa, H. Ike, Y. Murata, R. Shirasu, M. Kumazaki","doi":"10.5984/JJPNSOCLASERDENT.8.7","DOIUrl":"https://doi.org/10.5984/JJPNSOCLASERDENT.8.7","url":null,"abstract":"The purpose of this study was to examine the depth into penetration of the tissue and the circulatory structure of the microvasculature after irradiation the Nd: YAG laser on the lingual dorsum of a 9-week-old male wistar rat.The Nd: YAG laser was irradiated against the tongue of rats under the following condition; the energy level; 1, 2 and 3-Watts for 1.0, 2.0 and 3.0 seconds.Wounds of tongue were observed macroscopically, microscopically and also examined by SEM. The following results were obtained; Microscopical findings: The penetration was observed until the lamina propria in 1W1S and 1W2S groupsThe penetration of 1W3S, 2W2S and 3W1S groups were observed still superior tranversus linguae layer and also were observed in the muscle layer for 3 second group.SEM findings: The capillary loops of the papillae and the lamina propria venure networks were damaged in 1W1S and 1W2S groups.Irradiation wounds disappeared in the capillary loops of the papillae and the lamina propria venure networks.In 1W3S, 2W2S and 3W1S groups, and also disappeared in the capillaries of muscle layer in 3 second groups.(J. Jpn. Soc. Laser Dent. 8: 7-15, 1997 Reprints request to Dr. MATSUMOTO)","PeriodicalId":187459,"journal":{"name":"Journal of Japanese Society for Laser Dentistry","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128051310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.5984/jjpnsoclaserdent.9.2
H. Ikeda, A. Kitamura, A. Irie, T. Inokuchi
A new photosensitizer Hematoporphyrin Oligomers (HpO) based photodynamic therapy (PDT) on mouse squamous cell carcinoma was studied. Morphological changes of the tumor after PDT was investigated by a transmission electron micros copy. One hour after PDT, bullous mitochondria were seen with irregular shaped inner cristae. After six hours, the inner cristae and outer membrane of mitochondria disappeared. Endonucleus vesicles appear ed. Heterochromatin increased in the nucleus. Forty-eight hours later, mitochondria had no longer its original feature. The outer layer of plasma membrane vanished away. Our study concludes that target organ HpO based PDT seems to be mitochondria. (J. Jpn. Soc. Laser Dent. 9:2-8, 1998 Reprint requests to Dr. IKEDA) Key words=Photodynamic therapy, Hematoporphyrin Oligomers, NR-S1 mouse squamous cell carcinoma キー ワー ド=光 化学 治療,ヘ マ トポル フ ィ リンオ リゴマ ー,NR-S1マ ウス扁 平上 皮癌
{"title":"Electron Microscopic Study on Mouse Tumor Cell Following Photodynamic Therapy with Hematoporphyrin Oligomers","authors":"H. Ikeda, A. Kitamura, A. Irie, T. Inokuchi","doi":"10.5984/jjpnsoclaserdent.9.2","DOIUrl":"https://doi.org/10.5984/jjpnsoclaserdent.9.2","url":null,"abstract":"A new photosensitizer Hematoporphyrin Oligomers (HpO) based photodynamic therapy (PDT) on mouse squamous cell carcinoma was studied. Morphological changes of the tumor after PDT was investigated by a transmission electron micros copy. One hour after PDT, bullous mitochondria were seen with irregular shaped inner cristae. After six hours, the inner cristae and outer membrane of mitochondria disappeared. Endonucleus vesicles appear ed. Heterochromatin increased in the nucleus. Forty-eight hours later, mitochondria had no longer its original feature. The outer layer of plasma membrane vanished away. Our study concludes that target organ HpO based PDT seems to be mitochondria. (J. Jpn. Soc. Laser Dent. 9:2-8, 1998 Reprint requests to Dr. IKEDA) Key words=Photodynamic therapy, Hematoporphyrin Oligomers, NR-S1 mouse squamous cell carcinoma キー ワー ド=光 化学 治療,ヘ マ トポル フ ィ リンオ リゴマ ー,NR-S1マ ウス扁 平上 皮癌","PeriodicalId":187459,"journal":{"name":"Journal of Japanese Society for Laser Dentistry","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132250882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.5984/JJPNSOCLASERDENT.26.67
K. Koba, Y. Kimura, Yoshishige Yamada, Y. Masuda, Yasuko Sato
{"title":"Vital Tooth Bleaching with KTP Laser: ―A Basic Study Using Brown Egg Shell―@@@―褐色鶏卵卵殻を使用した基礎研究―","authors":"K. Koba, Y. Kimura, Yoshishige Yamada, Y. Masuda, Yasuko Sato","doi":"10.5984/JJPNSOCLASERDENT.26.67","DOIUrl":"https://doi.org/10.5984/JJPNSOCLASERDENT.26.67","url":null,"abstract":"","PeriodicalId":187459,"journal":{"name":"Journal of Japanese Society for Laser Dentistry","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133147609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.5984/JJPNSOCLASERDENT.4.63
Yukio Nakamura, Takumasa Yoshida, K. Narushima, N. Tsuzuki, H. Wakabayashi, K. Kikuchi, Koukichi Matsumoto
CO2 and Nd: YAG lasers are usually used in the clinical field. Since it is generally known that infrared lasers has thermal side effect, which cause damage to the soft and hard tissues. With infrared lasers, thermal energy densities high enough to remove the soft and hard tissues lead to structural changes, which can be seen as cracks, necrotic zone and carbonization. Recently, it has been demonstrated that the soft and hard tissue can be removed without thermal damage by excimer laser irradiation. However, there are a few studies about the effects of the ArF excimer laser on the bone tissue. The purpose of this study was to investigate the changes of the bone structure by ArF excimer laser irradiation.ArF excimer laser was irradiated on the surface of the rat's mandibula under the follow ing irradiation conditions; wave length; 193nm, output; 0.12W, pulse repetition rate;10HZ, spot size; 1.0×3.3mm, irradiation time; 60 and 120 seconds. By using the extirpated mandibula, we examined the thermal change on the surface of the non-vital mandibula dur ing laser irradiation by thermography system. The temperature rise was 34°C after 60 sec onds and 45°C after 120 scconds. Histological and scanning electron microscopical studies were perfomed immediately after the irradiation. The ArF excimer laser beam produced de fect with clean-cut margins in both non-vital and vital mandibula. There was very minimal evidence of thermal damage on the surrounding tissue. The bottom of the defect revealed sawtooth appearance on histological sections and cone or clavate appearance when examined with a scanning electron microscope. These findings suggested that it is possible to remove the bone tissue without thermal changes by ArF excimer laser irradiation. The effectiveness of this laser can be attributed to the photoablation of the bone tissue. The mechanism of the ArF excimer laser in this study has not been clarified yet. Therefore more research is necessary before this newtype of ultraviolet laser may be used in the clinical field in the future.
{"title":"The Effect of the Rat's Mandibula by ArF Excimer Laser Irradiation","authors":"Yukio Nakamura, Takumasa Yoshida, K. Narushima, N. Tsuzuki, H. Wakabayashi, K. Kikuchi, Koukichi Matsumoto","doi":"10.5984/JJPNSOCLASERDENT.4.63","DOIUrl":"https://doi.org/10.5984/JJPNSOCLASERDENT.4.63","url":null,"abstract":"CO2 and Nd: YAG lasers are usually used in the clinical field. Since it is generally known that infrared lasers has thermal side effect, which cause damage to the soft and hard tissues. With infrared lasers, thermal energy densities high enough to remove the soft and hard tissues lead to structural changes, which can be seen as cracks, necrotic zone and carbonization. Recently, it has been demonstrated that the soft and hard tissue can be removed without thermal damage by excimer laser irradiation. However, there are a few studies about the effects of the ArF excimer laser on the bone tissue. The purpose of this study was to investigate the changes of the bone structure by ArF excimer laser irradiation.ArF excimer laser was irradiated on the surface of the rat's mandibula under the follow ing irradiation conditions; wave length; 193nm, output; 0.12W, pulse repetition rate;10HZ, spot size; 1.0×3.3mm, irradiation time; 60 and 120 seconds. By using the extirpated mandibula, we examined the thermal change on the surface of the non-vital mandibula dur ing laser irradiation by thermography system. The temperature rise was 34°C after 60 sec onds and 45°C after 120 scconds. Histological and scanning electron microscopical studies were perfomed immediately after the irradiation. The ArF excimer laser beam produced de fect with clean-cut margins in both non-vital and vital mandibula. There was very minimal evidence of thermal damage on the surrounding tissue. The bottom of the defect revealed sawtooth appearance on histological sections and cone or clavate appearance when examined with a scanning electron microscope. These findings suggested that it is possible to remove the bone tissue without thermal changes by ArF excimer laser irradiation. The effectiveness of this laser can be attributed to the photoablation of the bone tissue. The mechanism of the ArF excimer laser in this study has not been clarified yet. Therefore more research is necessary before this newtype of ultraviolet laser may be used in the clinical field in the future.","PeriodicalId":187459,"journal":{"name":"Journal of Japanese Society for Laser Dentistry","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114410868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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