## 1 Introduction  
Zirconia is highly popular in clinical use for dental restorations, due to its exceptional flexural strength, chemical resistance, and good aesthetics [1]. Depending on whether a glass-matrix phase is present or absent, or whether the material contains an organic matrix highly filled with ceramic particles, all-ceramic materials can be classified into three families: (1) glass-matrix ceramics, (2) polycrystalline ceramics, and (3) resin-matrix ceramics [2]. However, unlike other dental ceramic materials, zirconia has a polycrystalline phase composition without a glass phase composition, as well as good chemical stability and acid corrosion resistance. Owing to this, conventional bonding technology suitable for silica-based ceramics is not effective for zirconia. Thus, an important scientific problem in the use of zirconia materials is the effective treatment of zirconia to improve its surface roughness and mechanical properties [3]. Contemporary surface treatment technologies used for zirconia ceramics include airborne particle abrasion (APA), acid etching, laser etching, silicon coating, pre-treatment agents, and other technologies and combinations thereof. APA with 50 \(\upmu\)m Al\({}_{2}\)O\({}_{3}\) under 0.2 MPa pressure at a distance of 10 mm from the zirconia surface has been found to be an effective method for improving bond strength [4]. However, this approach may lead to sub-surface damage to the zirconia, resulting in microcracks and debris, which may reduce the mechanical properties of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP), thus affecting its longevity. Studies have shown that APA may cause fractures in zirconia restorations and influence the long-term durability of the bond strength between zirconia ceramics and resin [5; 6; 7]. The reduced retention rate after APA may be related to microcracks in the zirconia, and APA may, therefore, have an adverse effect on flexural strength and other long-term mechanical properties of restorations [3]. Other surface modification methods are therefore required to replace aluminum oxide APA and to avoid adverse effects on the mechanical properties and long-term durability of zirconia [4]. Recently, scholars worldwide have trialed advanced technologies, such as thermal acid etching solutions [7; 8], plasma technology [6; 9], tribochemical silica coating [10; 11], ultrashort-pulse lasers [12; 13], and fusion sputtering technology [14; 15], to treat zirconia surfaces. Thermal chemical etching solutions have been employed for pre-treating zirconia ceramics. It has been found that this method improves roughness and, therefore, increases the zirconia-resin cement bond strength [7]; however, the configuration of a safe and effective thermal acid etching solution remains unclear, as thermal acid etching may also affect the physical properties of zirconia [8]. The application of plasma technology for the surface modification of zirconia ceramics has also been studied. [PERSON] et al. [6] reported that non-thermal plasma modification without significant damage promoted adequate adhesion, but the bond strength was not found to be significantly different from that under aluminum oxide APA. Plasma modification resulted in a significant increase in the surface free energy of the zirconia ceramic, but no significant changes in surface roughness were observed. The application of plasma treatment in zirconia bonding, therefore, cannot replace APA [9]. Tribochemical silica coating is a commonly used silicon coating technology at present, which uses 30 \(\upmu\)m alumina particles covered with silica for sandblasting at 0.23 MPa on the zirconia surface [10]. By increasing the silicon content on the surface of the zirconia, the silica layer can react with the cement-containing silane [11]. As a result, through copolymerization between the silane and the resin cement, the bond strength between the zirconia resin can be improved.