Complete arch digital implant scans in the edentulous maxilla: Trueness and time efficiency based on scan body height, splinting, location, and scanner system.

Statement Of Problem Accurate digital scans of edentulous arches remain challenging. Combined effects of scan body height, splinting, location, and scanner on complete arch implant trueness have not been clarified. Purpose The purpose of this in vitro study was to evaluate scan body height, splinting, implant location (anterior/posterior), and 3 intraoral scanners on the trueness of 6-implant edentulous maxillary scans. Material And Methods Polyetheretherketone (PEEK) scan bodies with cylindrical geometry and 3 different heights (4.5 mm, 6 mm, 8 mm) were tightened on straight mini-unit abutments on 6 Morse implants in a 3-dimensionally (3D) printed resin model. Scans were performed splinted and nonsplinted using 3 different intraoral scanners (PrimeScan PS; TRIOS 5 TR; Infinite IF). Deviations at implant locations were quantified in micrometers. Trueness analysis was measured by overlaying scans in the Geomagic X Design software program. Deviations were quantified by root mean square (RMS) values. Statistical analysis was performed in Jamovi (v.2.3), including normality assessment (Shapiro-Wilk) and nonparametric comparisons using the Kruskal-Wallis and Mann-Whitney U tests with Dwass, Steel, Critchlow-Fligner (DSCF) Multiple Comparisons tests (α=.05). Results Scan body height significantly affected trueness in all scanner groups (P<.001). The highest implant scan trueness was obtained with a 4.5-mm scan body height using the TR scanner (P<.001), and the lowest trueness was seen with an 8-mm scan body height and IF scanner (P<.001). Splinting did not affect the trueness for 4.5-mm scan bodies (P=.392) but significantly improved scan trueness for 6-mm and 8-mm scan bodies (P<.001). Regarding scanning time, splinting reduced the mean time for 6-mm scan bodies with both TR (P=.005) and PS scanners (P=.002) and for 8-mm scan bodies with IF (P=.016. Within the location, scanner height had a significant effect on trueness (P<.001). Conclusions Scan body height and scanner type significantly affected the trueness of complete arch scans. The 4.5-mm scan bodies demonstrated the best trueness across scanners. Although splinting did not improve trueness, it contributed to reduced scanning time for taller scan bodies (6- and 8-mm). Short scan bodies (4.5 mm) enabled higher trueness in the posterior region, while intermediate height (6 mm) led to higher trueness in the anterior region.