## 4 Discussion
Thus, the cleaning effectiveness of sandblasting was compared to that of the Ivoclean method. Results indicated that both cleaning methods were equally effective in terms of shear bond strength. Furthermore, when both cleansing methods were applied (Group C), the results remained within the same SBS range. It appeared that the cleaning agents did not produce any significant effects on the ceramic surface under in vitro conditions, supporting the acceptance of the first null hypothesis. However, it should be noted that these results cannot be directly extrapolated for in vivo applications, as the laboratory conditions for this specific experiment did not include intraoral contaminants. Therefore, ceramic surfaces were treated as \"clean\" and not \"cleaned\". Some studies claimed that sandblasting as the sole surface treatment does not yield adequate bond strength [37; 38; 39; 40], while others argue that a sandblasted surface may initially achieve high SBS, but this strength significantly decreases after artificial aging [41]. Samples in Group E underwent the same surface modifications as those in Group D, with the additional Ivoclean treatment in the latter. However, this addition did not appear to influence bond strength values. This result was expected since the experiment was conducted in the absence of intraoral contaminants. It is essential to note that there might still be potential negative effects or interference in bonding when using Ivoclean. According to the results of the current study, the influence of Ivoclean was neither positive nor negative regarding SBS. Therefore, the second null hypothesis should also be accepted. In similar publications, [PERSON] et al. [29] compared the influence of cleansing methods on saliva-contaminated ceramic surfaces in terms of micro-SBS. However, they tested the cleaning effect in cases where contamination followed sandblasting and/or acid etching. They concluded that, for lithium disilicate surfaces, Ivoclean or 0.5% sodium hypochlorite did not completely restore bond strength compared to their effect on non-contaminated surfaces. [PERSON] et al. [19] tested the same sequence of post-modification contamination and argued that the best practice for lithium disilicate surfaces is re-etching with HF acid for contaminated surfaces, when compared to water-spray rinsing and Ivoclean application. The same results were also presented by [PERSON] et al. [21], who found HF to provide the best post-contamination SBS values when compared to Ivoclean, phosphoric acid, sodium hypochlorite solution, and restorative cleansing agents, although the authors did not consider this a clinically important difference. However, [PERSON] et al. [34] claimed that HF-etched lithium disilicate surfaces perform better in bond strength after contamination when treated with Ivoclean in comparison to water-spray, phosphoric acid, and isopropanol cleaning. According to the authors, this difference becomes more prominent after the samples are aged through thermocycling, providing evidence of the higher stability of the bond. This stability is associated with the observed rounded zirconia particles on the ceramic surface after treatment with Ivoclean [34]. Surfaces in Group E received no other treatment than application of Monobond Etch & Prime. This alone was adequate for the SBS of this group to outperform that of the negative control group, it having non-treated surfaces in which only pre-testing failures were experienced. In fact, the SBS for this group reached comparable values to those of groups with surface pre-treatment values. This suggests that, for application to clean surfaces, a single-bottle agent that modifies and silanizes ceramic surfaces provides a reliable alternative in terms of SBS. Consequently, the third null hypothesis of the study, stating that surface silanization does not have a significant effect on SBS, was rejected. These results are also supported by various previous studies examining different lithium disilicate surface treatments with and without silane application.