## 4 Discussion
The chemical adhesion between zirconia and 10-MDP relies on the phosphate group in the functional monomer. This reaction creates zirconium phosphate salts that are chemically stable. These salts improve the bonding between resin and zirconia because they can withstand heat and hydrolytic breakdown, thus making them stronger [27]. Moreover, the 10-MDP monomer has a methacrylate group, which can be used to copolymerize with other methacrylate-based monomers, such as methacrylate-based resin cement. This notion has been demonstrated by the chemical assessment of the zirconia-primed surface [28]. Furthermore, the 10-MDP molecule and other methacrylate phosphate functional monomers reduce the likelihood of phase transformation from tetragonal to monoclinic zirconia, thereby contributing to the preservation of zirconia's mechanical strength [29]. In the present study, we did not employ phosphoric acid or alcohol to decontaminate saliva since these substances can only partially remove saliva contamination from zirconia surfaces [10; 30]. According to an earlier investigation, washing with phosphoric acid did not enhance the resin-zirconia bond because it has the ability to lower the surface energy of zirconia [30]. Additionally, a phosphorous residue may be deposited on the zirconia surface through the interaction between zirconia and phosphoric acid. This would hinder the chemical adhesion between the zirconia and 10-MDP molecules, subsequently weakening their bonding [12; 31; 32]. The shear bond strengths of zirconia decontaminated with Ivoclean, Katana Cleaner, and Tooth Primer decontamination are comparable. Therefore, the second null hypothesis, which states that there is no difference in the effects of the investigated decontamination techniques, was also not rejected. Additionally, unlike the decontamination or cleaning protocols utilized in this investigation, Katana Cleaner and Tooth Primer achieved a shear bond strength comparable to the control (uncontaminated) group, whereas Ivoclean did not. Ivoclean consists of zirconia particles in a hyper-saturated solution. Phosphorus is one of the contaminants that Ivoclean adsorbs when applied to contaminated substrates. Thus, contaminants can be eliminated from the zirconia surface. Recent X-ray photoelectron spectroscopy investigations indicated the effectiveness of Ivoclean for use as a ceramic cleaner since it removes deposits of organic substances, including saliva [13; 33; 34]. Moreover, Ivoclean increases the surface energy of the decontaminated ceramic [33]. This explains why the SBS of group 4 was significantly higher compared with groups 2 and 3. Statistical analysis revealed no significant difference among Ivoclean, Katana Cleaner, and Tooth Primer. Katana Cleaner is a commercial product specifically formulated for cleaning zirconia ceramic surfaces. The cleaning solution consists of 10-MDP, triethanolamine, poly(ethylene glycol), stabilizer, water, and dyes. Upon applying and rubbing Kanata Cleaner onto the saliva-contaminated restoration's intaglio surface, the hydrophobic portion of the 10-MDP molecule adheres to the contaminant and lowers surface tension by encircling it. The contaminant is subsequently removed when rinsed with water [35; 36]. In addition, the 10-MDP molecule can interact with the hydroxyl groups of the hydrated oxide layer on the zirconia surface, which cannot be rinsed off with water, thereby enhancing the bond strength between the resin cement and zirconia interphase. Previous investigations have determined the bonding ability and formation of chemical interactions at the interface. Consequently, numerous investigations have demonstrated its efficacy on zirconia surfaces contaminated with blood and saliva [35; 37; 38; 39; 40]. Tooth Prime is a self-etching solution that the manufacturer recommends for use intraorally to condition prepared teeth. It is composed of 10-MDP, 2-hydroxyethyl methacrylate (2-HEMA), hydrophilic aliphatic dimethacrylate, accelerators, and water.