- 著者
- Makoto NODA Yuji OKUDA Jiro TSURUKI Yoshito MINESAKI Yasumi TAKENOUCHI Seiji BAN
- 出版者
- The Japanese Society for Dental Materials and Devices
- 雑誌
- Dental Materials Journal (ISSN:02874547)
- 巻号頁・発行日
- vol.29, no.5, pp.536-541, 2010 (Released:2010-10-14)
- 参考文献数
- 21
- 被引用文献数
- 58 50
The purpose of this study was to characterize the surface damages of zirconia by Nd:YAG dental laser irradiation through a systematic evaluation of the associated microstructural changes. Disk specimens of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/Al2O3 nanocomposite) were irradiated by Nd:YAG dental laser. The specimens were characterized using scanning electron microscopy, X-ray diffractometry, and wavelength dispersive X-ray spectroscopy. Every single irradiated spot was indicated by a circular black pit surrounded by a circular raised rim with a sunken depression at the center. On surface changes, many cracks were formed inside each irradiated pit. On changes in elemental composition, the concentration of oxygen decreased while that of zirconium increased. After heating in air, the assembly of circular black pits turned white, although the depression and raised rim remained. This study showed that Nd:YAG dental laser irradiation induced cracking and reduced oxygen content on the surface of zirconia. Consequently, these phenomena reduced the mechanical strength of zirconia. Therefore, Nd:YAG dental laser welding should not be performed on tetragonal zirconia.
- 著者
- Makoto NODA Yuji OKUDA Jiro TSURUKI Yoshito MINESAKI Yasumi TAKENOUCHI Seiji BAN
- 出版者
- The Japanese Society for Dental Materials and Devices
- 雑誌
- Dental Materials Journal (ISSN:02874547)
- 巻号頁・発行日
- pp.1009140074, (Released:2010-09-18)
- 参考文献数
- 21
- 被引用文献数
- 42 50
The purpose of this study was to characterize the surface damages of zirconia by Nd:YAG dental laser irradiation through a systematic evaluation of the associated microstructural changes. Disk specimens of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/Al2O3 nanocomposite) were irradiated by Nd:YAG dental laser. The specimens were characterized using scanning electron microscopy, X-ray diffractometry, and wavelength dispersive X-ray spectroscopy. Every single irradiated spot was indicated by a circular black pit surrounded by a circular raised rim with a sunken depression at the center. On surface changes, many cracks were formed inside each irradiated pit. On changes in elemental composition, the concentration of oxygen decreased while that of zirconium increased. After heating in air, the assembly of circular black pits turned white, although the depression and raised rim remained. This study showed that Nd:YAG dental laser irradiation induced cracking and reduced oxygen content on the surface of zirconia. Consequently, these phenomena reduced the mechanical strength of zirconia. Therefore, Nd:YAG dental laser welding should not be performed on tetragonal zirconia.
- 著者
- Hisanori Kosuge Makoto Noda Tsunekazu Kakuta Yukio Kishi Mitsuaki Isobe Fujio Numano
- 出版者
- International Heart Journal Association
- 雑誌
- Japanese Heart Journal (ISSN:00214868)
- 巻号頁・発行日
- vol.42, no.2, pp.265-269, 2001 (Released:2003-02-25)
- 参考文献数
- 6
- 被引用文献数
- 24 31
A 53-year-old woman was hospitalized for general fatigue and palpitations. An electrocardiogram showed ST elevation and T wave inversion in leads II, III, aVF, and V4~6. Cardiac catheterization was performed since the echocardiogram demonstrated the existence of a left ventricular apical aneurysm. Left ventriculography showed an aneurysm of the apex. An endomyocardial biopsy specimen from the left ventricular apical wall demonstrated typical noncaseating granulomas with giant cells. The patient was diagnosed as having cardiac sarcoidosis. There was no evidence suggesting involvement of other systemic organs. Cardiac sarcoidosis should be considered within a spectrum of diseases that cause left ventricular aneurysm.