Chemical surface modification of lithium disilicate needles of a silica-based ceramic after HF-etching and ultrasonic bath cleaning: Impact on the chemical bonding with silane

Recommendations to obtain the best bonding silica-based ceramics are prepare its surface by hydrofluoric-acid HF etching and regular application of a silane. This study investigated how HF-etching following ultrasonic water bath cleaning (recommended protocol improve with composite resin), modifies chemistry lithium disilicate glass-ceramic impacts chemical Lithium discs (IPS Emax Press, Ivoclar Vivadent) were mirror polished, etched 9% for 20 s rinsed 1 min under water. Two post-etching compared: (1) no additional (2) immersion in 4 min. Morphology evolution surfaces was carried out scanning electron microscopy. Chemical changes studied using X-ray Photoelectron Spectroscopy Nano Auger Electron analyses. Identification compounds formed fluorine based on High Resolution Transmission Tlectronic Microscopy . Residues left after etching, salts, eliminated cleaning. However, analyses showed presence needles associated among others lithium. HR-TEM validates Li2SiF6 crystallized phased. A mechanism explain silane when phase is Li2Si2O5 needles, proposed. leads formation contain LiSi2F6 nano-precipitates which helps