- 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
- 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.2022-243, (Released:2023-01-12)
- 参考文献数
- 30
- 被引用文献数
- 5
This review describes the development of ultra-high translucent zirconia (referred to as UHTZ) using new manufacturing technology and its characterization results. The development of UHTZ was primarily due to the adoption of two basic manufacturing technologies, “Cyclic CIP” and “Plus Y Technology”. This manufacturing technology could provide stable processing characteristics, which improves chipping resistance during milling. Furthermore, the enlargement factor (processing coefficient) for UHTZ is smaller than those for conventional products. In general, the higher the light transmittance, the lower the flexural strength. Despite its extremely high translucency, the most significant feature of UTHZ is that its flexural strength is comparable to that of 5Y. Furthermore, UHTZ has higher chemical durability and uniform microstructure, which results in less wear on the opposing teeth and superior discoloration resistance. Therefore, UHTZ is a new option for inlay, onlay, and laminate veneer applications, where lithium disilicate glass ceramics has been widely used.
- 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.