Scanning electron microscope comparative surface evaluation of glazed-lithium disilicate ceramics under different irradiation settings of Nd:YAG and Er:YAG lasers

To evaluate the surface of glazed lithium disilicate dental ceramics after irradiation under different irradiation settings of Nd:YAG and Er:YAG lasers using a scanning electron microscope (SEM). Three glazed-press lithium disilicate ceramic discs were treated with HF, Er:YAG, and Nd:YAG, respective...

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Published in:The Angle orthodontist 2018-01, Vol.88 (1), p.75-81
Main Authors: Viskic, Josko, Jokic, Drazen, Jakovljevic, Suzana, Bergman, Lana, Ortolan, Sladana Milardovic, Mestrovic, Senka, Mehulic, Ketij
Format: Article
Language:English
Subjects:
Acid Etching, Dental
Ceramics - radiation effects
Dental Bonding - methods
Dental Porcelain - radiation effects
Dentistry
Hydrofluoric Acid
Lasers, Solid-State
Materials Testing
Microscopy, Electron, Scanning
Original
Surface Properties
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Summary:To evaluate the surface of glazed lithium disilicate dental ceramics after irradiation under different irradiation settings of Nd:YAG and Er:YAG lasers using a scanning electron microscope (SEM). Three glazed-press lithium disilicate ceramic discs were treated with HF, Er:YAG, and Nd:YAG, respectively. The laser-setting variables tested were laser mode, repetition rate (Hz), power (W), time of exposure (seconds), and laser energy (mJ). Sixteen different variable settings were tested for each laser type, and all the samples were analyzed by SEM at 500× and 1000× magnification. Surface analysis of the HF-treated sample showed a typical surface texture with a homogenously rough pattern and exposed ceramic crystals. Er:YAG showed no effect on the surface under any irradiation setting. The surface of Nd:YAG-irradiated samples showed cracking, melting, and resolidifying of the ceramic glaze. These changes became more pronounced as the power increased. At the highest power setting (2.25 W), craters on the surface with large areas of melted or resolidified glaze surrounded by globules were visible. However, there was little to no exposure of ceramic crystals or visible regular surface roughening. Neither Er:YAG nor Nd:YAG dental lasers exhibited adequate surface modification for bonding of orthodontic brackets on glazed lithium disilicate ceramics compared with the control treated with 9.5% HF.
ISSN:0003-3219
1945-7103
DOI:10.2319/062017-408.1