## 2 Materials and Methods
### Preparation of the Specimens  
Experimental surfaces were obtained by sectioning blocks of lithium disilicate glass ceramic (Vintage LD, Shofu). Cylinders were cut using a low-speed precision cutting machine (Buehler Isomet, Leinfelden-Echterdingen, Germany) equipped with a diamond saw, resulting in a thickness of 2 mm and a diameter of 8 mm. Each disk was then divided into four equal parts using the same cutting device. Subsequently, each part was securely embedded in self-curing acrylic resin material (NT Newton Aycliffe Cold Repair/Self Curing Acrylic, Toros Dental, Antalya, Turkey) inside plastic cylinders precisely matching the shear-testing machine's slot (OM100, Odeme Dental Research, Luzerna, SA, Brazil), with an external diameter of 20 mm. The exposed surfaces of each specimen were meticulously cleaned and polished using a rotational polishing machine (Jean Wirtz TG 250, Dusseldorf, Germany) at 200 rpm, employing 600-grit carbide abrasive papers (Apex S  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** & **Type** & **Composition** & **Manufacturer** \\ \hline \multirow{3}{*}{Vintage LD Press} & Lithium disilicate glass-ceramic & Monoclinic lithium disilicate (Li\({}_{2}\)Si\({}_{2}\)O\({}_{5}\)) crystals & Shofu, Kyoto, Japan \\ \hline \multirow{6}{*}{Variolink Esthetic LC} & Light-cure resin cement & Monomer: UDMA and methacrylate monomers & \\  & Light-cure & Inorganic fillers: \(\cong\)38\% & Ivoclar Vivadent, \\  & & resin cement & by volume of ytterbium & Schaan, \\  & & trifluoride and spheroid & Lichtenstein \\  & & mixed oxide. Particle size & \\  & & is 0.04–0.2 \(\upmu\)m & \\ \hline \multirow{3}{*}{Monobond Plus} & Universal & Silane methacrylate, & Ivoclar Vivadent, \\  & adhesive system & phosphoric methacrylate, & Schaan, \\  & & and sulfide methacrylate & Lichtenstein \\ \hline \multirow{3}{*}{Monobond Etch \& Prime} & Alcoholic-aqueous solution of ammonium polyfluoride, silane methacrylate, & Ivoclar Vivadent, \\  & & single-component ceramic primer & polyfluoride, silane methacrylate, & Schaan, \\  & & ceramic primer & methacrylate, \\  & & and colorant & \\ \hline \multirow{3}{*}{AdheSE Universal} & Light-curing single-component universal adhesive & 10-MDP, MCAP, & \\  & Light-curing single-component & HEMA, Bis-GMA, D3 MA, water, ethanol, highly dispersed silicon dioxide, initiators & Ivoclar Vivadent, \\  & & and stabilizers & Schaan, \\ \hline \multirow{3}{*}{Ivoclean} & Universal & Polyethylenedylcol, sodium hydroxide, & \\  & cleaning paste & ZrO2, water & Lichtenstein \\ \hline \multirow{3}{*}{AquaAbrasion} & Abrasive & \multirow{3}{*}{29-\(\upmu\)m Al\({}_{2}\)O\({}_{3}\) particles} & Velopex, \\  & Al\({}_{2}\)O\({}_{3}\) powder & & Harlesden, UK \\ \hline \hline \end{tabular} Bis-GMA: bis-phenol A diglyoldylmethylacrylate; D3 MA: methyl-D3 methacrylate; HEMA: hydroxyl-ethyl methacrylate; MCAP: methacylated carboxylic acid poly; UDMA: urethane dimethacrylate; 10-MDP: 10-methacryloyloxydexyl dihydrogen phosphate.  
\end{table}
Table 1: The technical characteristics of the tested materials according to the manufacturers.  
system, Buehler, Lake Bluff, IL, USA) and a continuous water supply (50 mL/min) for 20 s to ensure uniformity across all surfaces.