Cerec omnicam

The previously described industrial precision scanner was used to scan the 3D printed Co-Cr master model to obtain the reference dataset. Digital impressions of the master model were performed using five IOSs (CEREC Omnicam (Dentsply Sirona, York, PA, USA), CS 3600 (Carestream Health, Rochester, NY, USA), i500 (Medit, Seoul, Korea)), iTero Element (Align Technology, San Jose, CA, USA), and TRIOS 3 (3Shape A/S, Copenhagen, Denmark)) (Table 1). For each scan, the spheres were scanned until no void was observed, and then the scanning procedures for the IOSs were performed along the occlusal surface starting from the left second molar to the right second molar, followed by the lingual and buccal side in the same experimental setting by an operator under ambient fluorescent lighting without the aid of additional lighting. No contrast powder was dusted prior to scanning. Additional scans were made to capture voided area of the cylinders that were critical for measurement. A total of 10 scans were performed by each IOS.

Four months after implant placement, temporary crowns and abutments were removed.
In the TG group of patients, final impressions were recorded using an intraoral scanner (Cerec Omnicam, Dentsply Sirona, York, PA, USA) after scanbody positioning.
These digital impressions, in the form of STL files, were sent to the laboratory for the realization of the final prosthesis.
In the CG group of patients, transfer copings were positioned and mono-component mono-phase impressions made with a polyether (Impregum Penta, 3M ESPE, Milan, Italy) were taken using the pick-up technique.
The antagonist arch impressions were taken in irreversible hydrocolloid (Alginate CA37 Fast Set, Cavex Holland BV, Harleem, The Netherlands).
Then, the impressions were sent to the laboratory for the realization of the final prosthesis in zirconia ceramic (Figure 3).

The prepared #51, #53, and #75 master dies were placed on the typodont model one by one and digitized with an intraoral scanner (CEREC Omnicam; Dentsply Sirona, York, US). To replicate the external form of fiberglass crowns, the “biocopy” tool of the CEREC software (SW 4.6, Dentsply Sirona) was used. For this purpose, prefabricated fiberglass crowns were placed on the corresponding master dies and scanned with the CEREC Omnicam. The scanning process took approximately 5 min for each tooth. Preparation margins were drawn by the “automatic margin finder” tool, and deviations from the marked margin line were corrected manually. The die spacer parameter was set as 120 μm for all teeth, and the software automatically designed virtual crowns based on the scans of the fiberglass crowns. Ten CAD/CAM crowns for each master die (#51, #53, and #75) were milled from resin-ceramic blocks (CERASMART 270; GC Dental Products, Tokyo, Japan) by using a clinical type milling unit (CEREC MC XL; Dentsply Sirona) (N = 30). The milling time of each crown was about 10 min.
The sample size and test groups of the study are presented in Table 1.