Effects of scan body material, length and top design on digital implant impression accuracy and usability: an in vitro study

다국어 초록 (Multilingual Abstract)

Purpose. This study evaluated how implant scan body (ISB) design affects trueness and operator convenience of digital implant impressions. The null hypothesis stated no significant differences in trueness or usability between ISB designs. Materials and methods. A cast metal model with nine implants and silicone mucosal masks (1 mm and 3 mm thickness) were used. Seven ISB prototypes were developed by modifying a commercial ISB (ELOS Accurate IO2A-B, ELOS Medtech) in four aspects: length (30% shorter and 50% longer), material (polyetheretherketone (PEEK) or titanium), surface reflectance (polished or aluminium oxide-blasted titanium), and top surface (concave top and screw holes enlarged by 100% and 200%). Each prototype was scanned ten times using an intraoral scanner (NeoScan1000, Neoss), with a desktop scanner (E3, 3Shape) providing reference scans. Deviations in depth, angulation, and rotation were analyzed in CAD software (GOM Inspect, Zeiss). Statistical analysis included the Welch test (P < .05) and Games-Howell post hoc test (P < .007). Results. Material affected depth accuracy; blasted titanium (89 ± 86 µm) and polished titanium (80 ± 72 µm) outperformed PEEK (149 ± 131 µm). Shorter ISBs showed greater angular deviations (0.64 ± 0.70°) compared to control (0.31 ± 0.21°). Rotational deviations were not significant. Scanning times increased for reflective, longer ISBs with reduced top areas, while shorter ISBs improved usability. Conclusion. ISB design influences digital impression accuracy. Titanium ISBs with reduced reflectivity improve trueness, and larger screw holes enhance usability. Shorter ISBs reduce scanning time but compromise angular trueness. Stitching errors remain the primary source of depth inaccuracies.