Influence of different scan body design features and intraoral scanners on the congruence between scan body meshes and library files: An in vitro study.

Statement Of Problem: Implant scan bodies (ISBs) present with a variety of features, including diverse design geometries and manufacturing materials. How these features influence the congruence between the clinically obtained mesh file and the software-based library file of the scan body during the alignment stage within the computer-aided design (CAD) software program is unclear. It is also uncertain how these features influence the scanning accuracy of different scanners.

Purpose: The purpose of this in vitro study was to investigate how various scan body shapes manufactured from different materials influence the scanning accuracy of 6 intraoral scanners (IOSs) and 1 desktop scanner.

Material And Methods: A 3-dimensionally (3D) printed cast fitted with 4 different implant analogs and their corresponding scan bodies (Straumann Cares RN Mono; Straumann, MIS V3 SP; MIS, Paltop SP; Paltop and TV70; TRI) was scanned using 6 intraoral scanners (Primescan; Dentsply Sirona, TRIOS 3; 3Shape A/S, TRIOS 5; 3Shape A/S, Medit i-700; Medit, Fussen S6000; Fussen, and Runyes 3DS; Runyes) and 1 desktop scanner (7series; Dental Wings). A metrology mesh comparison software program was used for analysis. Inferences were drawn using a univariate repeated measures 2-way ANOVA. Post hoc analysis was conducted with pairwise Bonferroni tests (α=.05).

Results: A significant 2-way interaction was found between scanner model and scan body model, (F [5.518, 49.659]=36.251, P<.001). The mean absolute deviation for the different scanners ranged between 21 µm and 35 µm across all scan bodies, but the model of the scan body influenced the deviation of the scanner. The mean absolute deviation for the different scan bodies ranged from 19 µm to 46 µm across all scanners, but the model of the scanner influenced the deviation of the scan body.

Conclusions: Regarding implant scan body features, a design with a less complex shape and fewer sharp line angles and a design with a cylindrical shape exhibited statistically significantly higher congruence between the clinical mesh and the software library files. Regarding intraoral scanners, Primescan had a statistically significantly lower mean absolute deviation compared with that of the other scanners across all scan bodies tested.