## 5 Conclusions  
Within the limitations, in the literature, there is no study that applied indirect ultrasonic vibration for fiber post placement. In this sense, the present study is the first. The results showed that:  
1. When both cement materials were evaluated within themselves, the irrigation procedures (NaOCI, NaOCI and EDTA, passive ultrasonic irrigation of NaOCI and EDTA) had no significant effect on bond strength. However, for Panavia V5, higher bond strength values were obtained by NaOCI irrigation or passive ultrasonic irrigation of NaOCI and EDTA. Therefore, when using Panavia V5, it may be recommended to use these two procedures instead of NaOCI irrigation. In the case of Rely X U200, although there was no significant difference between the irrigation procedures. NaOCI irrigation showed higher bond strength values, in accordance with the manufacturer's recommendations. NaOCI irrigation can be recommended for this cement material;
2. When NaOCI irrigation was applied, no difference was found between the bond strengths of the resin cements. However, NaOCI and EDTA irrigation or passive ultrasonic irrigation of NaOCI and EDTA provided higher bond strength values for Panavia V5 cement than RelyX U200;
3. When Panavia V5 was applied, higher bond strength was observed in the middle section rather than in the coronal section. When Rely X U200 was applied, there was no difference between the bond strengths of the sections;
4. No difference was found between manual placement and indirect ultrasonic vibration applications in terms of bond strength. No difference was stated between the sections in the manual method placement of the posts. However, when indirect ultrasonic vibration was applied, the middle section showed higher bond strength values. As the effects of the materials and techniques we applied on bond strength are more pronounced in the middle section, it can be said that indirect ultrasonic vibration has a positive effect on bond strength.  
It is hoped that the findings obtained from this in vitro study will shed light on the clinical applications, and these results should be confirmed in long-term in vivo studies.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14209523/s1](https://www.mdpi.com/article/10.3390/app14209523/s1)]([https://www.mdpi.com/article/10.3390/app14209523/s1](https://www.mdpi.com/article/10.3390/app14209523/s1)), Table S1: Four-way analysis of variance results for bond strength values (MPA). Table S2: Interactions of factors.  
**Author Contributions:** Idea, hypothesis, experimental design: L.B.A. Performed the experiments: N.C. Wrote the manuscript: [PERSON], L.B.A. and B.G. Proofread the manuscript: [PERSON] and B.G. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This study was supported by the project numbered B-2106 of the Ordu University Scientific Research Projects Coordination Office.  
**Institutional Review Board Statement:** In order to conduct this study, the approval of the ethics committee was obtained from the Ordu University Clinical Research Ethics Committee with decision number 2021/265 (3 December 2021).  
**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.  
**Data Availability Statement:** The original contributions presented in the study are included in the article; further inquiries can be directed to the corresponding author.  
**Conflicts of Interest:** The authors declare no conflicts of interest.