## 2 Case Presentation  
A 54-year-old female patient visited the clinic with missing teeth 46 and 47. The patient mentioned that the extraction of teeth was performed over 10 years ago because of severe dental caries. Unilateral chewing habit on the left side was found owing to loss of teeth on the right posterior side. The patient had no medical history or temporomandibular disorders. Two implants (OneQ-SL, Dentis, Daegu, Korea) were placed with the insertion torque of 40 Ncm using an open flap technique, and transmucosal healing abutments were then connected on the day of the surgery. The protocol of surgical and prosthetic treatment of this study was approved by the Institutional Review Board of Kyungpook National University dental hospital (2019-08-01-00).  
After a healing period of 3 months, a silicone impression (Aquasil Ultra XLV Regular Set and Aquasil Ultra Heavy, Dentsply Sinora, Philadelphia, PA, USA) was taken for the implants using an open tray technique with pick-up type impression copings. The fabricated stone cast was digitized using a desktop scanner (IDC S1, Amann Girrbach, Koblach, Austria) and transferred to the dental CAD software (IDC D1, Amann Girrbach, Koblach, Austria) where monotype custom prosthetic abutments and interim prosthesis were designed (Figure 1).  
The interim prosthesis was fabricated with subtractive manufacturing using a 5-axis milling machine (ICD MILL 5X, Amann Girrbach, Koblach, Austria) and methacrylic acid ester-based cross-linked resin blocks (Ceramill TEMP, Amann Girrbach, Koblach, Austria). The custom prosthetic abutments (T16 Al-4V ELI, Perryman Company, Houston, PA, USA) were connected to the implants, followed by cementation of the interim prosthesis using a glass ionomer cement (Fuji I, GC, Tokyo, Japan) (Figure 2). Occlusal contact points were set at maximum intercuspation, and all the lateral contacts were removed.  
After a 3-month neuromuscular adaptation period, the interim prosthesis was removed using a reverse crown ejector (Crown remover, YDM, Tokyo, Japan), and new impressions and vertical dimension of occlusion were recorded with an intraoral optical scanner (CS3600, Carestream, Rochester, NY, USA). The scan data of the oral cavity in the polygon file format (PLY) were loaded on to the CAD software, and the abutment scan parts were replaced with the abutment designs using the point-based best-fit algorithm embedded in the software (Figure 3). This image substitution enabled the setting of an image of the intact custom abutment in the scan data. Thereafter, the design of the interim crowns was recalled, and the occlusal surface and the design margins were modified as per the newly created vertical dimension.  
Figure 1: Design of the monotype custom prosthetic abutments and interim prosthesis.  
Figure 2: (**a**) Connection of the custom prosthetic abutments to the implants. (**b**) Cementation of the interim prosthesis on the abutments.  
The morphological change in the prosthesis in the occlusal surface was investigated by superimposing the original and modified designs of the prosthesis in image analysis software (Geomagic DesignX, 3D Systems, Rock Hill, SC, USA) (Figure 4).  
The final design of the crowns was converted into monolithic zirconia prosthesis using the 5-axis milling machine and a zirconium dioxide block (Prettau, Zirkonzhan, Bruneck, Italy). On the day of delivery, the definitive monolithic zirconia prosthesis was cemented using a resin-based luting cement (RelyX Unicem Clicker; 3M ESPE AG, Seefeld, Germany). Stable occlusal contact points were maintained at maximum intercuspation during the 8-month follow-up after the restoration delivery (Figure 5).  
Figure 4: Superimposed occlusal image between the original and modified designs of the prosthesis.  
Figure 3: Image overlapping and replacement of the abutment design with the intraoral scan data.