Accuracy of one-versus two-phase photogrammetry implant impression system: an in-vitro study

Dental implants using digital technologies have become more popular for partial and fully edentulous patients. This in-vitro study aimed to compare the accuracy of one- and two-phase photogrammetry implant impression techniques. Six abutment-level implant analogs (screw-retained abutment diameter 4.6 mm, Straumann) were parallelly attached to the maxillary edentulous model. Scan bodies (CARES® RC Mono, Straumann) were put in place and scanned with an E4 lab scanner. Cylindrical abutments with bars (Dental system, 3Shape) were then designed and exported as a "Reference file". The study samples were divided into two groups, each containing 15 samples; Group I involved placing and capturing all six scan bodies (PIC transfers) using a stereo camera (PIC legacy), and Group II involved recording four anterior PIC transfers using a stereo camera. Following the import of the recorded data, a dental system was used to design cylindrical abutments with bars. Then, PIC transfers were removed, except the first left premolar, and the remaining PIC transfers were placed on the first molar on both sides, and records were made. Finally, the exported files were incorporated into a reverse engineering software program (Geomagic Design X) for comparison through best-fit alignment. It revealed no significant differences in linear, angular, and overall discrepancies between Groups I and Group II. Both groups exhibit discrepancies that are within the prescribed range for well-fitted complete arch implant support prostheses (< 100 µm). The capture protocols of one- and two-phase photogrammetry implant impressions present similar linear, angulation, and overall discrepancies. Both one- and two-phase photogrammetry implant impressions can be used in the complete arch implant support prostheses.