## 2 Materials and Methods
### Sample Preparation  
The materials used in this study, along with their application techniques, are presented in Table 1.  
The sample size was determined based on a power analysis using G*Power software (v3.1; Heinrich Heine University, Dusseldorf, Germany). A minimum of 15 specimens per group was calculated to detect a medium effect size (f = 0.40) with a statistical power of 0.80 and an alpha level of 0.05 using one-way ANOVA. A total of 105 samples were fabricated from a nanofill resin composite (Clearfil Majesty Esthetic, Kuraray, Japan) using a Teflon mold with a diameter of 4 mm and a height of 6 mm. Specimens were prepared by inserting \begin{table}
\begin{tabular}{l l l} \hline \hline
**Materials and Manufacturer Details** & **Composition** & **Directions for Use** \\ \hline Control & No treatment & \\ \hline  & & \\  & & \\  & 10-MDP, HEMA, silane, & Apply the adhesive to the entire \\ Single Bond Universal Adhesive & dimethacrylate resins, & tooth structure and rub it in \\ (3M ESPE, St. Paul, MN, USA) & Vitrebond copolymer, filler, ethanol, & for 20 s. \\  & & dimethacrylate resins, & Direct a gentle stream of air \\  & & Vitebond copolymer, filler, ethanol, & over the liquid for about 5 s. \\  & & water, initiators & Harden the adhesive with \\  & & commonly used light curing \\  & & & for 10 s. \\ \hline Composite Primer & Monofunctional methacrylate, & \(\clubsuit\) & Apply a thin layer of composite \\ (GC Corporation, Tokyo, Japan) & urethane dimethacrylate (UDMA), & primer to surface. \\  & camphorquinone & \(\clubsuit\) & Light cure using an LED curing \\  & & unit for 20 s. \\ \hline  & & \\  & & \\  & & \\  & & \\  & & \\  & & \\  & & \\ \hline  & Silane: Methacryloxymethyl & \\ Silane + PQ1 & Trimethoxysilane & \(\circ\) & Apply silane with a mini brush \\ (Ultradent Products Inc., & PQ1: Mineral 2-hydroxyethyl) & & tip. Let it evaporate for 60 s. \\ South Jordan, UT, USA) & methacrylate, camphorquinone, & \(\circ\) & Then, apply PQ1, as described \\  & ethyl alcohol & & in G4. \\ \hline  & Bis-GMA, HEMA, ethanol, & \\ Clearfil Universal Bond & 10-MDP, hydrophilic aliphatic & \(\Box\) & Apply bond to the entire \\ (Kuraray Noritake Dental Inc., & dimethacrylate, colloidal silica, & adhered surfaces. Light-cure \\ Okayama, Japan) & DL-camphorquinone, silane coupling & & bond with a dental curing unit \\  & agent, accelerators & & for 10 s. \\ \hline  & & \\  & & \\  & & \\ \end{tabular}
\end{table} 
Table 1: Materials, compositions, and instructions for use. uncured resin composite into the mold placed on a glass slide covered by a mylar strip and covered by a second strip and a glass slide to stabilize the mold. The specimens were light-cured every 2 mm increment from the top, according to the manufacturer's specifications, using a light-curing device (Elipar 10, 3M ESPE, St. Paul, MN, USA). The specimens were stored in distilled water for 14 days prior to aging. They were then subjected to thermal cycling 10,000 times (\(\approx\)1 year of aging) between 5 and 55 \({}^{\circ}\)C, with a dwell time of 20 s and a transfer time of 3 s. After the aging process, the aged specimens were roughened with a silicon carbide grinding paper (320-grit) to standardize the surfaces, then etched with phosphoric acid for 10 s, washed, and dried with air/water spray. One hundred and five specimens were randomly allocated to seven groups (\(n\) = 15) according to the repair procedures to be tested: G1. control--no adhesive; G2. Single Bond Universal Adhesive; G3. composite primer; G4. PQ1; G5. Silane + PQ1; G6. Clearfil Universal Bond; G7. All-Bond Universal. Randomization was performed using a computer-generated random sequence created in Microsoft Excel. The group assignments were carried out by an independent researcher who was blinded to the adhesive protocols to minimize selection bias.