Reinforcement of Bonding Strength between Dental Y‐TZP and Resin via Nano‐Thin and Conformal SiO₂ Films by Atomic Layer Deposition

Abstract

for many years. Unlike glass ceramics, Y-TZP cannot be etched by hydrofluoric acid under normal conditions (room temperature and ambient atmosphere). [4] Thus, the roughness of Y-TZP surface is generally achieved by grit blasting.Y-TZP is unlikely to react with silane coupling agents because of its low SiO 2 content (less than 1%). [5,6] Thus, primers containing phosphate ester monomers are typically used in combination with alumina grit blasting to improve the chemical bonding between Y-TZP and resin. [7] Among them, 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) is most commonly used. However, the disadvantage of 10-MDP is that it cannot maintain long-term bonding stability in a complex oral environment (0-67 °C); [8] for example, the shear strength of 10-MDP after 10 000 thermocycles is ≈18.0 ± 3.7 MPa. [9] In addition to primers, the bonding strength of Y-TZP/resin has been also increased by depositing SiO 2 films combined with silane coupling agents. [10][11][12][13] Common methods used for SiO 2 film deposition include sol-gel, tribochemical SiO 2 coating, plasma spraying, and chemical vapor deposition; [14][15][16] although, all these methods have their drawbacks. First, the SiO 2 films are not firmly attached to the Y-TZP and thus are easily peeled off. Second, the coverage of the SiO 2 films on the surface of Y-TZP is insufficient and uneven, and the thickness of the films cannot be controlled. [17,18] Plasma spraying requires high temperatures (2700-11 700 °C), which take a long time to reach, and the procedure is relatively complex. [19] These drawbacks limit the clinical applications of SiO 2 film deposition on the bonding surface of Y-TZP prostheses.Atomic layer deposition (ALD) was first proposed by Suntola and Antson in 1977. [20] ALD may produce nanoscale films with high precision, [21] controllable thickness, and extreme uniformity. [22,23] ALD has already been widely used to deposit films on a variety of materials and is thus expected to overcome the drawbacks of other common SiO 2 film deposition methods because of the following ALD advantages. [24] 1. The films are deposited by gas-solid chemical reactions; thus, the films are firmly and stably bonded with the substrate. [25] The retentive strength of zirconia crowns is derived from resin cement, and the weak interface between the two is the main reason for their failure. In this work, nano-thin silica (SiO 2 ) films of precisely controlled thickness are deposited over yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics via atomic layer deposition (ALD). The deposited films are modified using a silane coupling agent, which significantly improves the bonding strength between Y-TZP and resin. Scanning electron microscopy shows that the SiO 2 films deposited by ALD are uniform and can accurately maintain the morphology of grit-blasted Y-TZP. Spectroscopic ellipsometry demonstrates that the films are nano-thin, with thicknesses in the range of 5.58-26.58 nm. The increase in the shear bond strength is attributed to the chemic...

Shear Bond Strength to Enamel, Mechanical Properties and Cellular Studies of Fiber-Reinforced Composites Modified by Depositing SiO2 Nanofilms on Quartz Fibers via Atomic Layer Deposition

“…Furthermore, our previous study showed that the fatigue resistance of the material would decrease if the SiO 2 nanofilm became too thick. 29 This may be related to factors such as thermal and internal stress between the nanofilms. 30 …”

“…Furthermore, our previous study showed that the fatigue resistance of the material would decrease if the SiO 2 nanofilm became too thick. 29 This may be related to factors such as thermal and internal stress between the nanofilms. 30 However, due to the specific of chewing movement, most researches on FRC primarily focus on the detection of their inherent performance but fail to simulate the failure modes of FRC in the oral cavity.…”