## 2 Materials and Methods
### Cementation of the Posts  
Then, each group was divided into four according to the used cement type (self-adhesive resin cement system or the self-etch resin cement system) and cement placement technique (manual placement and indirect ultrasonic vibration) (\(n=10\)). The contents of the resin cements and the primers used in our study are presented in Table 1. The self-etching resin cement was designated as Panavia V5 (Kuraray Medical, Inc., Tokyo, Japan). The self-adhesive resin cement was designated as Rely X U200 (RXU; 3M ESPE, Seefeld, Germany). Following the manufacturer's instructions, both cements were applied to the 1.2 mm diameter fiber posts' (Cytec Blanco, Hahnenkratt, Konigsbach-Stein, Germany) surface using mixing tips. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Primer/Cement** & **Composition** & **Manufacturer** \\ \hline \multirow{2}{*}{Clearflí ceramic primer plus} & 3-MPS(methacryloxymethyltrimethoxysilane), 10-MDP & Kuraray Dental, Tokyo, Japan \\  & (methacryloyloxydecyl dihydrogen phosphate), Ethanol & Kuraray Dental, Tokyo, Japan \\ \hline \multirow{3}{*}{Panavia V5 tooth primer} & 10-MDP(methacryloyloxydecyl dihydrogen phosphate), & \\  & HEMA (hydroxyethyl methacrylate), hydrophilic aliphatic & Kuraray Dental, Tokyo, Japan \\ \hline \multirow{3}{*}{Panavia V5 paste} & Bis-GMA (bisphenol A diglycidyl-methacrylate), & \\  & TEGDMA (triethylene glycol dimethacrylate), silanated & \\  & barium glass, colloidal silica, surface-treated aluminum & Kuraray Dental, Tokyo, Japan \\ \cline{1-1}  & oxide filler, hydrophobic aromatic dimethacrylate, & \\ \cline{1-1}  & hydrophilic aliphatic dimethacrylate, di-camphorquinone, & \\ \cline{1-1}  & initiators, accelerators, pigments & \\ \hline \multirow{3}{*}{Rely X U200} & Base: Methacrylate monomers containing phosphoric acid & \\ \cline{1-1}  & groups, methacrylate monomers, initiators, stabilizers, & \\ \cline{1-1}  & rheological additives & \\ \cline{1-1}  & Catalyst: Methacrylate monomers, alkaline fibers, & \\ \cline{1-1}  & silanated fillers, initiator components, stabilizers, & \\ \cline{1-1}  & pigments, rheological additives, zirconia/silica fillers. & \\ \cline{1-1}  & Clicker delivery system & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Contents of resin cements and primer used in our study. **Subgroup 1--**Panavia V5 + manual placement (\(n\) = 10). Before Panavia V5 cementation, 35% phosphoric acid was applied to the post surface and held for 5 s. Then, it was irrigated and dried slightly. Afterward, Ceramic Primer Plus (Kuraray Medical, Inc., Tokyo, Japan) was applied to the post surface and dried slightly. Panavia V5 Tooth Primer (Kuraray Medical, Inc., Tokyo, Japan) was applied to the prepared post space for 20 s. The excess was removed with paper points and dried slightly. Panavia V5 self-etch resin cement was activated via otolix tips and applied to the post surface, and then, the post was placed into the post space until it went into the prepared post cavity with finger fissure. Excess material was removed, and the cement was light-polymerized for 40 s perpendicular to the fiber post with a Blue LED (Elipar S10, 3M ESPE, Neuss, Germany) at an intensity of 1200 mW/cm\({}^{2}\). **Subgroup 2--**Panavia V5 + indirect ultrasonic vibration (\(n\) = 10). Panavia V5 cementation procedures were applied as in subgroup 1. After the glass fiber post was manually placed in the post space, a START-X #5 ultrasonic tip (Dentsply Maillefer, Ballaiques, Switzerland) (Figure 2) was applied to the top of the fiber post indirectly, through the amalgam fulvar, for 3 s using VDW Ultra (VDW, Germany) as an ultrasonic device at REDO Mode. After indirect ultrasonic vibration, the cement was light-polymerized for 40 s perpendicular to the fiber post with a Blue LED (Elipar S10, 3M ESPE, Neuss, Germany) at an intensity of 1200 mW/cm\({}^{2}\). **Subgroup 3--**Rely X U200 + manual placement (\(n\) = 10).