## 4 Discussion  
In our study, the first hypothesis could not be confirmed because no significant difference was found when the effect of irrigations applied to the post cavity on the bond strength was evaluated. When self-etch resin cement material was used, a higher bond strength was observed in both sections compared to the self-adhesive resin cement material, and the second hypothesis was rejected. When the sections were compared, our third hypothesis was rejected because a higher bond strength was observed in the middle segment, and our fourth hypothesis was rejected because there was no significant difference between the placement methods. In our study, in parallel with similar studies, no statistically significant effect of the irrigation methods applied to the post cavity on the bond strength of the post was observed when the same cement material was applied [20, 21, 22]. In previous studies, it was reported that the stresses transmitted during the push-out test were more uniformly distributed when the segments were in the range of 1-1.5 mm, while the stresses transmitted to the specimens were more irregular when the push-out test was applied on segments with a thickness of 2 mm [23, 24, 25]. Therefore, in the present study, 1.2 mm thick segments were prepared. A force was applied at a speed of 1 mm/min by means of a 0.8 mm diameter rounded metal tip positioned on the posts at the centers of the dentin discs, with reference to a study in which limitations related to push-out studies were identified [26]. Previous studies have reported that single NaOCl irrigation has a negative effect on the bond strength of fiber posts when using resin-based cements for cementation [27, 28, 29]. [PERSON] et al. [29] reported that NaOCl's action on organic dentinal compounds can lead to collagen breakdown, which can negatively affect the bonding ability of fiber posts to the root canal dentin. It has been shown in several studies that a prolonged exposure of dentin to high concentrations of NaOCl can have a detrimental effect on bond strength [30, 31]. Figure 6: Distribution rate of failure types according to level and cement types. In a recent study, NaOCl and EDTA irrigation have been shown to increase the bond strength of post-cor systems when used in post space irrigation [32]. In their systematic review, [PERSON] et al. [33] stated that the use of NaOCl + EDTA can be recommended for post space irrigation. The lack of a statistically significant difference between the irrigation protocols used in our study could be due to the NaOCl concentration and the duration of NaOCl application. NaOCl irrigation at the appropriate concentration and duration may have prevented the adverse effects of high concentration and prolonged use of NaOCl on dentin and the adhesive surface shown in previous studies [29; 30; 31]. According to [PERSON] et al. [34], self-adhesive cements do not induce a complete demineralization of the smear layer or a decalcification of dentin. This indicates that the presence of the smear layer is not a limiting factor for adhesion, as confirmed in previous studies [35; 36]. [PERSON] et al. [36] reported that this effect was not observed for RelyX U200, since microhardness values were not affected by NaOCl irrigation. This may be a reason why NaOCl does not have a negative effect on the bond strength of RelyX U200 cement. At the same time, EDTA application is not recommended by the manufacturer for RelyX U200 [36]. EDTA application could theoretically reduce the chemical bonding efficiency of the self-adhesive resin to hydroxyapatite [37; 38; 39]. [PERSON] et al. [36], in a study using two different self-adhesive cement materials, found that better removal of the smear layer was not associated with the bond strength of glass fiber posts when RelyX U200 was used. In our study, similar to [PERSON] et al. [36], NaOCl irrigation showed higher values in the U200 group compared to NaOCl and EDTA irrigation, but the difference between irrigation methods was not significant.