## 2 Materials and Methods  
A typodont secondary primary molar (85) was prepared following the anatomical form of a tooth with the following parameters: 1 mm axial preparation, 1.5 mm occlusal reduction, and a 1 mm chamfer margin in a pediatric dental model (AK-6/2M, Frascao GmbH, Tettnang, Germany). All sharp edges and undercuts were rounded. To obtain a virtual model, the model was digitized using an intraoral scanner (CEREC Omnicam; Sirona Dental Systems, Bensheim, Germany). The virtual model in a Standard Tessellation Language (STL) file was transferred to a web-based AI software, version number V.4.X.X, (DentBird Solutions; Imagoworks, Gangnam-gu, Seoul, Republic of Korea) for the restoration design. The restorations were designed by selecting cement film thicknesses of 50 \(\upmu\)m, and manual adjustments of the designs were not made. The final design was exported in an STL file for the production process. A specimen size of 10 for each group was based on previous studies [24; 25]. A total of 30 crowns were made using additive and subtractive manufacturing techniques (DLP, SLA, and milling). Tested materials and their production techniques are presented in Table 1.  
For the DLP 3D printing process, the specimens were printed using a 3D printer using DLP technology (Asiga Max UV; Asiga, Anaheim Hills, CA, USA) and Saremco permanent crown resin from Crowntech (Saremco Dental AG; Rebstein, Switzerland). For SLA 3D printing, samples were printed using a 3D printer using SLA technology (Formalabs Form 3B, Formlabs, Somerville, MA, USA) and permanent crown resin from Formlabs (Somerville, MA, USA). The specimens were printed following the standardized printing protocols provided by the manufacturers, and post-processes were applied in line with the recommendations of the manufacturers. The production of the restorations in the SLA and DLP 3D printing methods was carried out following the printing parameters recommended by the manufacturers. The occlusal plane of the restorations was positioned with a 0-degree orientation, facing the building platform horizontally, and the printing thickness was selected as 50 \(\upmu\)m. The milling process was performed in a CAM device (Redon, Hybrid Dental CNC; Redon Technology). Esthetic composite blocks (Tetric CAD; Ivoclar Vivadent, Schaan, Liechtenstein) were used to produce the milled specimens. The prepared typodont tooth was scanned for the production of standard resin dies. The dies (\(n=30\)) were produced using model resin (Formlabs Inc., Somerville, MA, USA) and a 3D printer (Formlabs Form 3, Formulas, Somerville, MA, USA) and were randomly divided into 3 groups according to manufacturing techniques. Self-adhesive resin cement (GCEM-ONE, GC, Tokyo, Japan) was used as a luting agent for the cementation. As a silane coupling agent, g-Multi Primer (GC, Tokyo, Japan) was applied to the bonding surface and dried. After placing a sufficient amount of automatically mixed cement inside the crown, it was seated on the resin  
\begin{table}
\begin{tabular}{p{42.7 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline  
die with finger pressure and cured using a light-cured device (VALO; Ulradent Products, Inc.; South Jordan, UT, USA). Excess cement was then removed with a probe. The triple-scan method was used to assess crown adaptation [4; 26]. All surfaces of the crown (C) and die (D) specimens before cementation and the die and crown (DC) after cementation were scanned with a 3D intraoral dental scanner (Trios 3, 3 Shape, Copenhagen, Denmark), and the scans were saved in STL file format (Figure 1). The STL files obtained from the scans were imported into the design module of Mimics Innovation Suite 26.0 (Materialise, Leuven, Belgium), specifically 3-matic 18.0 (Materialise, Leuven, Belgium) software. 3-matic working files were created according to the name of the scanning device and the order of the scans.