## 2 Materials and Methods
### Technical Note: Adjustment of the Virtual Surgical Guide before Fabrication  
1. Plan the implant placement according to the patient's treatment using CGI software (R2 GATE v1.1.1; Megagen, Daegu, Republic of Korea) (Figure 2A). Then, export the CGI surgical guide from the CGI software into a standard tessellation language (STL) format file (Figure 2B). Figure 1: Schematic of the procedure. Figure 2: Design of the implant surgical guide. (**A**) Planned implant position with preoperative radiographs. (**B**) virtual surgical guide. 2. Import the STL format file into a mesh editing software (Meshmixer; Autodesk Co, San Rafael, CA, USA) (Figure 3A). 3. Create the cylinder using a mesh editing software (Figure 3B). Then, adjust the size of the cylinder to a diameter of 5.2 mm by adding 0.2 mm to the original hole-size (5 mm) to compensate for the shrinkage of the resin material. 4. Use the \"Face Group\" function to separate the base of the cylinder and the guide hole in the surgical guide (Figure 3C). 5. Use the \"Create Pivot\" function to set up a reference point for alignment. Set the reference point at the base of the cylinder and the guide hole of the surgical guide (Figure 3D,E). 6. Use the \"Align\" function to superimpose the reference point. Select the reference point of the cylinder and hold down the Shift key while selecting the reference point of the surgical guide (Figure 3F). Make sure it is aligned to the correct position (Figure 3G). 7. Use the \"Transform\" function to move the cylinder so it can contact the entire guide hole (Figure 3H). 8. Use the \"Boolean Difference\" function to adjust the size of the guide hole. Select the surgical guide, hold down the Shift key while selecting the cylinder, and then select the \"Boolean Difference\" function (Figure 3I). 9. Check the adjusted guide hole (Figure 3J). Then, export the surgical guide with a guide hole of 5.2 mm diameter from the mesh editing software into a STL format file. 2.2. _Technical Note: Identification of the Surgical Guide for the Optimized Guide Hole Size_ 1. Fabricate the surgical guides with guide hole sizes of 5.0 mm (original size) and 5.2 mm (+0.2 mm) in diameter using a 3D printer (MegPrinter; Megagen, Daegu, Republic of Korea) with photosensitive liquid resins (RAYDEN SG; Ray, Seoul, Republic of Korea). 2. Assess the size of the hole by inserting an implant surgical guide drill (R2 GATE; Megagen, Daegu, Republic of Korea) into the hole of the surgical guides with guide hole sizes of 5.0 mm and 5.2 mm in diameter (Figure 4). The insertion of the drill was impossible at 5.0 mm (Figure 4A), while it was possible at 5.2 mm (Figure 4B). Figure 3: Method to adjust the size of the guide hole using Meshmixer. (**A**) Importing virtual surgical guide. (**B**) Creating a cylinder. (**C**) Partial segmentation of the cylinder and surgical guide. (**D**) Setting a reference point at the base of the cylinder. (**E**) Setting a reference point in the guide hole of the surgical guide. (**F**) Alignment with the cylinder and surgical guide. (**G**) Identification of alignment. (**H**) Cylinder movement. (**I**) Deletion of the overlapping parts of the cylinder and surgical guide. (**J**) Identification of the adjusted guide hole. * [3] Perform 'Adjustment of the virtual surgical guide' steps for the fabrication of surgical guides with guide hole sizes of 5.19 mm, 5.18 mm, and 5.17 mm in diameter. Using this process, it is possible to determine the minimum usable clearance between the hole and the drill. * [4] Perform the 2 steps for assessment of the surgical guides with guide hole sizes of 5.19 mm, 5.18 mm, and 5.17 mm. The insertion of the drill was possible at 5.19 mm and 5.18 mm (Figure 5A,B), but was not possible at 5.17 mm (Figure 5C). Therefore, the value of 5.18 mm between 5.19 mm and 5.17 mm was determined as the minimum usable tolerance. * [5] Fabricate 10 surgical guides with guide holes of 5.18 mm for repeatability. Then, assess the size of the hole by inserting an implant surgical guide drill.