evaluation of the effect of auxiliary geometric device on measurement trueness and scanning time in full-arch implant impressions.

PURPOSE

This study aimed to evaluate the effect of clinically practical auxiliary geometric devices (AGD) on measurement trueness and scan time in full-arch implant-supported prostheses, focusing on different intraoral scanners (IOS) and implant angulations.

MATERIALS AND METHODS

Four implants were planned in an edentulous maxillary arch and divided into two groups based on posterior implant angulation: Model A (Parallel) and Model B (30°). Each model was evaluated under three auxiliary geometric devices (AGD) application types (std, agd1, agd2), and scanned using three different intraoral scanners (IOSs) [3Shape Trios 3 (T), Medit i700 (M), and Cerec Primescan (PS)], resulting in nine groups per model (n = 10). Scanning times and faulty scans were recorded. A conventional impression (CON) was taken as a control and digitized with a desktop scanner. Trueness was analyzed using Geomagic Control X, with statistical significance set at < .05.

RESULTS

Group B had higher RMS values than Group A (40.3 µm vs. 34.7 µm). T_std in Group A (51.4 µm) and T_std (53.1 µm) and Con (50.7 µm) in Group B exceeded the acceptable deviation limit. AGDs reduced deviations to acceptable levels in the Trios 3. The Primescan scanner had the shortest scanning times. AGD use, especially in T_agd2 and M_agd2, shortened scan times and eliminated erroneous scans.

CONCLUSION

The use of AGD has a significant impact on scanners' scanning trueness and time.