## 2 Materials and Methods  
This study follows the experimental model presented in Figure 1.  
Thirty implant suprastructure samples, divided into three groups according to the type of implant abutment and the material, were included in this study. The sample size was calculated using the software SigmaPlot 14.0 (Systat Software, Inc., San Jose, CA, USA). The sample size was calculated based on previous studies that have evaluated the mechanical performance of implant suprastructures after cyclic loading [10; 24; 25; 26]. Figure 1: Study model. The materials used for the specimens are presented in Table 1. The work protocol for manufacturing the specimens was in line with entirely digitally based CAD/CAM technology. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Materials** & **Titanium Bases** & **Titanium Alloy Blanks** & **Zirconium Dioxide** & **Lithium Disilicate** \\
**GenTek\({}^{\text{TM}}\) TiBase (Zfx,** & **GenTek\({}^{\text{TM}}\) Pre-Milled** & **Katana (Kuraray** & **IPS e.max CAD** \\
**Zimmer Biomet,** & **Abtument Blank (Zimmer** & **Noritake, Tokyo, Japan)** & **(IvocalrVivadent,** \\
**Warsaw, IN, USA)** & **Biomet, Warsaw, IN, USA)** & **Noritake, Tokyo, Japan)** & **(Ivocalr,** \\ \hline Study groups & A & B, C & A, B & C \\ \hline \hline \end{tabular} The monolithic superstructures that were subjected to dynamic load testing were divided into 3 groups, according to the materials used, as presented in Table 2.  
\end{table} 
Table 2: Study groups. Figure 2: Study groups: (**a**) Group A; (**b**) Group B; and (**c**) Group C.  
The digital protocol for making the samples had the following sequence. A study maxillary model with installed TSV implants (Zimmer Biomet, Warsaw, IN, USA) in the area of the right central incisor and right first molar was prepared. A digital impression with an iFero Element intraoral scanner (Align Technology, San Jose, CA, USA) was taken. The file was exported into an \"stl\" format and thereby imported into ExoCad software (GmbH, Darmstadt, Germany) to design a monolithic zirconium crown over a GenTek titanium base (Zimmer Biomet, Warsaw, IN, USA) for Group A and a monolithic ceramic restoration over an individualized titanium superstructure for Groups B and C (Figure 3a,b). All abutments in Groups B and C were milled from customizable titanium abutments and GenTek(tm) Pre-milled Abutment Blanks (Zimmer Biomet, Warsaw, IN, USA) (Figure 4). The final crowns in Groups A and B were milled from Katana zirconia discs (Kuraray Noritake, Japan) in an inLab MC X5 machine (Dentsply Sirona, Charlotte, NC, USA). The crowns in Group C were made of IPS e.max CAD individual lithium disilicate blocks (IvoclarVivadent, Schaan, Liechtenstein) milled in an inLab MC XL machine (Dentsply Sirona, Charlotte, NC, USA). The sintering of the lithium disilicate monolithic crowns was performed in a Programat P300 furnace (Ivoclar Vivadent, Shaan, Liechtenstein), and that of the zirconium crowns in a Zirconmaster S furnace (VOP Ltd., Sofia, Bulgaria), followed by glazing. The cementation of the monolithic crowns in the Group A and C abutments was performed according to the manufacturer's instructions for lithium disilicate. Each sample was screw-retained over the implant and retigthened after 10 min to avoid the possibility of its loosening. The samples were stored in distilled water at 37 \({}^{\circ}\)C for a period of 24 h prior to testing. The implants were fixed in the holder of the fatigue testing machine immersed in polymethyl methacrylate. The samples were subjected to dynamic load in a computer-controlled 2-axis machine that simulated masticatory movements, Chewing Simulator CS-4  
Figure 4: Milled customized titanium alloy superstructures: (**a**) central incisor and (**b**) first molar. Figure 3: Digital designs of (**a**) central maxillary incisor and (**b**) upper first molar. (SD-Mechatronik, Westerham, Germany) (Figure 5), for 250,000 cycles, representing 1 year of clinical operation of the superstructures, at a frequency of 2 Hz.